pgbench.c

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/*
 * pgbench.c
 *
 * A simple benchmark program for PostgreSQL
 * Originally written by Tatsuo Ishii and enhanced by many contributors.
 *
 * src/bin/pgbench/pgbench.c
 * Copyright (c) 2000-2019, PostgreSQL Global Development Group
 * ALL RIGHTS RESERVED;
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without a written agreement
 * is hereby granted, provided that the above copyright notice and this
 * paragraph and the following two paragraphs appear in all copies.
 *
 * IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
 * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
 * DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 */

#ifdef WIN32
#define FD_SETSIZE 1024         /* must set before winsock2.h is included */
#endif

#include "postgres_fe.h"

#include <ctype.h>
#include <float.h>
#include <limits.h>
#include <math.h>
#include <signal.h>
#include <time.h>
#include <sys/time.h>
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>       /* for getrlimit */
#endif

/* For testing, PGBENCH_USE_SELECT can be defined to force use of that code */
#if defined(HAVE_PPOLL) && !defined(PGBENCH_USE_SELECT)
#define POLL_USING_PPOLL
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#else                           /* no ppoll(), so use select() */
#define POLL_USING_SELECT
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#endif

#include "common/int.h"
#include "common/logging.h"
#include "fe_utils/conditional.h"
#include "getopt_long.h"
#include "libpq-fe.h"
#include "pgbench.h"
#include "portability/instr_time.h"

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif


#define ERRCODE_UNDEFINED_TABLE  "42P01"

/*
 * Hashing constants
 */
#define FNV_PRIME           UINT64CONST(0x100000001b3)
#define FNV_OFFSET_BASIS    UINT64CONST(0xcbf29ce484222325)
#define MM2_MUL             UINT64CONST(0xc6a4a7935bd1e995)
#define MM2_MUL_TIMES_8     UINT64CONST(0x35253c9ade8f4ca8)
#define MM2_ROT             47

/*
 * Multi-platform socket set implementations
 */

#ifdef POLL_USING_PPOLL
#define SOCKET_WAIT_METHOD "ppoll"

typedef struct socket_set
{
    int         maxfds;         /* allocated length of pollfds[] array */
    int         curfds;         /* number currently in use */
    struct pollfd pollfds[FLEXIBLE_ARRAY_MEMBER];
} socket_set;

#endif                          /* POLL_USING_PPOLL */

#ifdef POLL_USING_SELECT
#define SOCKET_WAIT_METHOD "select"

typedef struct socket_set
{
    int         maxfd;          /* largest FD currently set in fds */
    fd_set      fds;
} socket_set;

#endif                          /* POLL_USING_SELECT */

/*
 * Multi-platform pthread implementations
 */

#ifdef WIN32
/* Use native win32 threads on Windows */
typedef struct win32_pthread *pthread_t;
typedef int pthread_attr_t;

static int  pthread_create(pthread_t *thread, pthread_attr_t *attr, void *(*start_routine) (void *), void *arg);
static int  pthread_join(pthread_t th, void **thread_return);
#elif defined(ENABLE_THREAD_SAFETY)
/* Use platform-dependent pthread capability */
#include <pthread.h>
#else
/* No threads implementation, use none (-j 1) */
#define pthread_t void *
#endif


/********************************************************************
 * some configurable parameters */

#define DEFAULT_INIT_STEPS "dtgvp"  /* default -I setting */
#define ALL_INIT_STEPS "dtgGvpf"    /* all possible steps */

#define LOG_STEP_SECONDS    5   /* seconds between log messages */
#define DEFAULT_NXACTS  10      /* default nxacts */

#define MIN_GAUSSIAN_PARAM      2.0 /* minimum parameter for gauss */

#define MIN_ZIPFIAN_PARAM       1.001   /* minimum parameter for zipfian */
#define MAX_ZIPFIAN_PARAM       1000.0  /* maximum parameter for zipfian */

int         nxacts = 0;         /* number of transactions per client */
int         duration = 0;       /* duration in seconds */
int64       end_time = 0;       /* when to stop in micro seconds, under -T */

/*
 * scaling factor. for example, scale = 10 will make 1000000 tuples in
 * pgbench_accounts table.
 */
int         scale = 1;

/*
 * fillfactor. for example, fillfactor = 90 will use only 90 percent
 * space during inserts and leave 10 percent free.
 */
int         fillfactor = 100;

/*
 * use unlogged tables?
 */
bool        unlogged_tables = false;

/*
 * log sampling rate (1.0 = log everything, 0.0 = option not given)
 */
double      sample_rate = 0.0;

/*
 * When threads are throttled to a given rate limit, this is the target delay
 * to reach that rate in usec.  0 is the default and means no throttling.
 */
double      throttle_delay = 0;

/*
 * Transactions which take longer than this limit (in usec) are counted as
 * late, and reported as such, although they are completed anyway. When
 * throttling is enabled, execution time slots that are more than this late
 * are skipped altogether, and counted separately.
 */
int64       latency_limit = 0;

/*
 * tablespace selection
 */
char       *tablespace = NULL;
char       *index_tablespace = NULL;

/*
 * Number of "pgbench_accounts" partitions.  0 is the default and means no
 * partitioning.
 */
static int  partitions = 0;

/* partitioning strategy for "pgbench_accounts" */
typedef enum
{
    PART_NONE,                  /* no partitioning */
    PART_RANGE,                 /* range partitioning */
    PART_HASH                   /* hash partitioning */
}           partition_method_t;

static partition_method_t partition_method = PART_NONE;
static const char *PARTITION_METHOD[] = {"none", "range", "hash"};

/* random seed used to initialize base_random_sequence */
int64       random_seed = -1;

/*
 * end of configurable parameters
 *********************************************************************/

#define nbranches   1           /* Makes little sense to change this.  Change
                                 * -s instead */
#define ntellers    10
#define naccounts   100000

/*
 * The scale factor at/beyond which 32bit integers are incapable of storing
 * 64bit values.
 *
 * Although the actual threshold is 21474, we use 20000 because it is easier to
 * document and remember, and isn't that far away from the real threshold.
 */
#define SCALE_32BIT_THRESHOLD 20000

bool        use_log;            /* log transaction latencies to a file */
bool        use_quiet;          /* quiet logging onto stderr */
int         agg_interval;       /* log aggregates instead of individual
                                 * transactions */
bool        per_script_stats = false;   /* whether to collect stats per script */
int         progress = 0;       /* thread progress report every this seconds */
bool        progress_timestamp = false; /* progress report with Unix time */
int         nclients = 1;       /* number of clients */
int         nthreads = 1;       /* number of threads */
bool        is_connect;         /* establish connection for each transaction */
bool        report_per_command; /* report per-command latencies */
int         main_pid;           /* main process id used in log filename */

char       *pghost = "";
char       *pgport = "";
char       *login = NULL;
char       *dbName;
char       *logfile_prefix = NULL;
const char *progname;

#define WSEP '@'                /* weight separator */

volatile bool timer_exceeded = false;   /* flag from signal handler */

/*
 * Variable definitions.
 *
 * If a variable only has a string value, "svalue" is that value, and value is
 * "not set".  If the value is known, "value" contains the value (in any
 * variant).
 *
 * In this case "svalue" contains the string equivalent of the value, if we've
 * had occasion to compute that, or NULL if we haven't.
 */
typedef struct
{
    char       *name;           /* variable's name */
    char       *svalue;         /* its value in string form, if known */
    PgBenchValue value;         /* actual variable's value */
} Variable;

#define MAX_SCRIPTS     128     /* max number of SQL scripts allowed */
#define SHELL_COMMAND_SIZE  256 /* maximum size allowed for shell command */

/*
 * Simple data structure to keep stats about something.
 *
 * XXX probably the first value should be kept and used as an offset for
 * better numerical stability...
 */
typedef struct SimpleStats
{
    int64       count;          /* how many values were encountered */
    double      min;            /* the minimum seen */
    double      max;            /* the maximum seen */
    double      sum;            /* sum of values */
    double      sum2;           /* sum of squared values */
} SimpleStats;

/*
 * Data structure to hold various statistics: per-thread and per-script stats
 * are maintained and merged together.
 */
typedef struct StatsData
{
    time_t      start_time;     /* interval start time, for aggregates */
    int64       cnt;            /* number of transactions, including skipped */
    int64       skipped;        /* number of transactions skipped under --rate
                                 * and --latency-limit */
    SimpleStats latency;
    SimpleStats lag;
} StatsData;

/*
 * Struct to keep random state.
 */
typedef struct RandomState
{
    unsigned short xseed[3];
} RandomState;

/* Various random sequences are initialized from this one. */
static RandomState base_random_sequence;

/*
 * Connection state machine states.
 */
typedef enum
{
    /*
     * The client must first choose a script to execute.  Once chosen, it can
     * either be throttled (state CSTATE_PREPARE_THROTTLE under --rate), start
     * right away (state CSTATE_START_TX) or not start at all if the timer was
     * exceeded (state CSTATE_FINISHED).
     */
    CSTATE_CHOOSE_SCRIPT,

    /*
     * CSTATE_START_TX performs start-of-transaction processing.  Establishes
     * a new connection for the transaction in --connect mode, records the
     * transaction start time, and proceed to the first command.
     *
     * Note: once a script is started, it will either error or run till its
     * end, where it may be interrupted. It is not interrupted while running,
     * so pgbench --time is to be understood as tx are allowed to start in
     * that time, and will finish when their work is completed.
     */
    CSTATE_START_TX,

    /*
     * In CSTATE_PREPARE_THROTTLE state, we calculate when to begin the next
     * transaction, and advance to CSTATE_THROTTLE.  CSTATE_THROTTLE state
     * sleeps until that moment, then advances to CSTATE_START_TX, or
     * CSTATE_FINISHED if the next transaction would start beyond the end of
     * the run.
     */
    CSTATE_PREPARE_THROTTLE,
    CSTATE_THROTTLE,

    /*
     * We loop through these states, to process each command in the script:
     *
     * CSTATE_START_COMMAND starts the execution of a command.  On a SQL
     * command, the command is sent to the server, and we move to
     * CSTATE_WAIT_RESULT state.  On a \sleep meta-command, the timer is set,
     * and we enter the CSTATE_SLEEP state to wait for it to expire. Other
     * meta-commands are executed immediately.  If the command about to start
     * is actually beyond the end of the script, advance to CSTATE_END_TX.
     *
     * CSTATE_WAIT_RESULT waits until we get a result set back from the server
     * for the current command.
     *
     * CSTATE_SLEEP waits until the end of \sleep.
     *
     * CSTATE_END_COMMAND records the end-of-command timestamp, increments the
     * command counter, and loops back to CSTATE_START_COMMAND state.
     *
     * CSTATE_SKIP_COMMAND is used by conditional branches which are not
     * executed. It quickly skip commands that do not need any evaluation.
     * This state can move forward several commands, till there is something
     * to do or the end of the script.
     */
    CSTATE_START_COMMAND,
    CSTATE_WAIT_RESULT,
    CSTATE_SLEEP,
    CSTATE_END_COMMAND,
    CSTATE_SKIP_COMMAND,

    /*
     * CSTATE_END_TX performs end-of-transaction processing.  It calculates
     * latency, and logs the transaction.  In --connect mode, it closes the
     * current connection.
     *
     * Then either starts over in CSTATE_CHOOSE_SCRIPT, or enters
     * CSTATE_FINISHED if we have no more work to do.
     */
    CSTATE_END_TX,

    /*
     * Final states.  CSTATE_ABORTED means that the script execution was
     * aborted because a command failed, CSTATE_FINISHED means success.
     */
    CSTATE_ABORTED,
    CSTATE_FINISHED
} ConnectionStateEnum;

/*
 * Connection state.
 */
typedef struct
{
    PGconn     *con;            /* connection handle to DB */
    int         id;             /* client No. */
    ConnectionStateEnum state;  /* state machine's current state. */
    ConditionalStack cstack;    /* enclosing conditionals state */

    /*
     * Separate randomness for each client. This is used for random functions
     * PGBENCH_RANDOM_* during the execution of the script.
     */
    RandomState cs_func_rs;

    int         use_file;       /* index in sql_script for this client */
    int         command;        /* command number in script */

    /* client variables */
    Variable   *variables;      /* array of variable definitions */
    int         nvariables;     /* number of variables */
    bool        vars_sorted;    /* are variables sorted by name? */

    /* various times about current transaction */
    int64       txn_scheduled;  /* scheduled start time of transaction (usec) */
    int64       sleep_until;    /* scheduled start time of next cmd (usec) */
    instr_time  txn_begin;      /* used for measuring schedule lag times */
    instr_time  stmt_begin;     /* used for measuring statement latencies */

    bool        prepared[MAX_SCRIPTS];  /* whether client prepared the script */

    /* per client collected stats */
    int64       cnt;            /* client transaction count, for -t */
    int         ecnt;           /* error count */
} CState;

/*
 * Thread state
 */
typedef struct
{
    int         tid;            /* thread id */
    pthread_t   thread;         /* thread handle */
    CState     *state;          /* array of CState */
    int         nstate;         /* length of state[] */

    /*
     * Separate randomness for each thread. Each thread option uses its own
     * random state to make all of them independent of each other and
     * therefore deterministic at the thread level.
     */
    RandomState ts_choose_rs;   /* random state for selecting a script */
    RandomState ts_throttle_rs; /* random state for transaction throttling */
    RandomState ts_sample_rs;   /* random state for log sampling */

    int64       throttle_trigger;   /* previous/next throttling (us) */
    FILE       *logfile;        /* where to log, or NULL */

    /* per thread collected stats */
    instr_time  start_time;     /* thread start time */
    instr_time  conn_time;
    StatsData   stats;
    int64       latency_late;   /* executed but late transactions */
} TState;

#define INVALID_THREAD      ((pthread_t) 0)

/*
 * queries read from files
 */
#define SQL_COMMAND     1
#define META_COMMAND    2

/*
 * max number of backslash command arguments or SQL variables,
 * including the command or SQL statement itself
 */
#define MAX_ARGS        256

typedef enum MetaCommand
{
    META_NONE,                  /* not a known meta-command */
    META_SET,                   /* \set */
    META_SETSHELL,              /* \setshell */
    META_SHELL,                 /* \shell */
    META_SLEEP,                 /* \sleep */
    META_GSET,                  /* \gset */
    META_IF,                    /* \if */
    META_ELIF,                  /* \elif */
    META_ELSE,                  /* \else */
    META_ENDIF                  /* \endif */
} MetaCommand;

typedef enum QueryMode
{
    QUERY_SIMPLE,               /* simple query */
    QUERY_EXTENDED,             /* extended query */
    QUERY_PREPARED,             /* extended query with prepared statements */
    NUM_QUERYMODE
} QueryMode;

static QueryMode querymode = QUERY_SIMPLE;
static const char *QUERYMODE[] = {"simple", "extended", "prepared"};

/*
 * struct Command represents one command in a script.
 *
 * lines        The raw, possibly multi-line command text.  Variable substitution
 *              not applied.
 * first_line   A short, single-line extract of 'lines', for error reporting.
 * type         SQL_COMMAND or META_COMMAND
 * meta         The type of meta-command, or META_NONE if command is SQL
 * argc         Number of arguments of the command, 0 if not yet processed.
 * argv         Command arguments, the first of which is the command or SQL
 *              string itself.  For SQL commands, after post-processing
 *              argv[0] is the same as 'lines' with variables substituted.
 * varprefix    SQL commands terminated with \gset have this set
 *              to a non NULL value.  If nonempty, it's used to prefix the
 *              variable name that receives the value.
 * expr         Parsed expression, if needed.
 * stats        Time spent in this command.
 */
typedef struct Command
{
    PQExpBufferData lines;
    char       *first_line;
    int         type;
    MetaCommand meta;
    int         argc;
    char       *argv[MAX_ARGS];
    char       *varprefix;
    PgBenchExpr *expr;
    SimpleStats stats;
} Command;

typedef struct ParsedScript
{
    const char *desc;           /* script descriptor (eg, file name) */
    int         weight;         /* selection weight */
    Command   **commands;       /* NULL-terminated array of Commands */
    StatsData   stats;          /* total time spent in script */
} ParsedScript;

static ParsedScript sql_script[MAX_SCRIPTS];    /* SQL script files */
static int  num_scripts;        /* number of scripts in sql_script[] */
static int64 total_weight = 0;

static int  debug = 0;          /* debug flag */

/* Builtin test scripts */
typedef struct BuiltinScript
{
    const char *name;           /* very short name for -b ... */
    const char *desc;           /* short description */
    const char *script;         /* actual pgbench script */
} BuiltinScript;

static const BuiltinScript builtin_script[] =
{
    {
        "tpcb-like",
        "<builtin: TPC-B (sort of)>",
        "\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
        "\\set bid random(1, " CppAsString2(nbranches) " * :scale)\n"
        "\\set tid random(1, " CppAsString2(ntellers) " * :scale)\n"
        "\\set delta random(-5000, 5000)\n"
        "BEGIN;\n"
        "UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
        "SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
        "UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
        "UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
        "INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
        "END;\n"
    },
    {
        "simple-update",
        "<builtin: simple update>",
        "\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
        "\\set bid random(1, " CppAsString2(nbranches) " * :scale)\n"
        "\\set tid random(1, " CppAsString2(ntellers) " * :scale)\n"
        "\\set delta random(-5000, 5000)\n"
        "BEGIN;\n"
        "UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
        "SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
        "INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
        "END;\n"
    },
    {
        "select-only",
        "<builtin: select only>",
        "\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
        "SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
    }
};


/* Function prototypes */
static void setNullValue(PgBenchValue *pv);
static void setBoolValue(PgBenchValue *pv, bool bval);
static void setIntValue(PgBenchValue *pv, int64 ival);
static void setDoubleValue(PgBenchValue *pv, double dval);
static bool evaluateExpr(CState *st, PgBenchExpr *expr,
                         PgBenchValue *retval);
static ConnectionStateEnum executeMetaCommand(CState *st, instr_time *now);
static void doLog(TState *thread, CState *st,
                  StatsData *agg, bool skipped, double latency, double lag);
static void processXactStats(TState *thread, CState *st, instr_time *now,
                             bool skipped, StatsData *agg);
static void append_fillfactor(char *opts, int len);
static void addScript(ParsedScript script);
static void *threadRun(void *arg);
static void finishCon(CState *st);
static void setalarm(int seconds);
static socket_set *alloc_socket_set(int count);
static void free_socket_set(socket_set *sa);
static void clear_socket_set(socket_set *sa);
static void add_socket_to_set(socket_set *sa, int fd, int idx);
static int  wait_on_socket_set(socket_set *sa, int64 usecs);
static bool socket_has_input(socket_set *sa, int fd, int idx);


/* callback functions for our flex lexer */
static const PsqlScanCallbacks pgbench_callbacks = {
    NULL,                       /* don't need get_variable functionality */
};


static void
usage(void)
{
    printf("%s is a benchmarking tool for PostgreSQL.\n\n"
           "Usage:\n"
           "  %s [OPTION]... [DBNAME]\n"
           "\nInitialization options:\n"
           "  -i, --initialize         invokes initialization mode\n"
           "  -I, --init-steps=[" ALL_INIT_STEPS "]+ (default \"" DEFAULT_INIT_STEPS "\")\n"
           "                           run selected initialization steps\n"
           "  -F, --fillfactor=NUM     set fill factor\n"
           "  -n, --no-vacuum          do not run VACUUM during initialization\n"
           "  -q, --quiet              quiet logging (one message each 5 seconds)\n"
           "  -s, --scale=NUM          scaling factor\n"
           "  --foreign-keys           create foreign key constraints between tables\n"
           "  --index-tablespace=TABLESPACE\n"
           "                           create indexes in the specified tablespace\n"
           "  --partitions=NUM         partition pgbench_accounts in NUM parts (default: 0)\n"
           "  --partition-method=(range|hash)\n"
           "                           partition pgbench_accounts with this method (default: range)\n"
           "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
           "  --unlogged-tables        create tables as unlogged tables\n"
           "\nOptions to select what to run:\n"
           "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
           "                           (use \"-b list\" to list available scripts)\n"
           "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
           "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
           "                           (same as \"-b simple-update\")\n"
           "  -S, --select-only        perform SELECT-only transactions\n"
           "                           (same as \"-b select-only\")\n"
           "\nBenchmarking options:\n"
           "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
           "  -C, --connect            establish new connection for each transaction\n"
           "  -D, --define=VARNAME=VALUE\n"
           "                           define variable for use by custom script\n"
           "  -j, --jobs=NUM           number of threads (default: 1)\n"
           "  -l, --log                write transaction times to log file\n"
           "  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
           "  -M, --protocol=simple|extended|prepared\n"
           "                           protocol for submitting queries (default: simple)\n"
           "  -n, --no-vacuum          do not run VACUUM before tests\n"
           "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
           "  -r, --report-latencies   report average latency per command\n"
           "  -R, --rate=NUM           target rate in transactions per second\n"
           "  -s, --scale=NUM          report this scale factor in output\n"
           "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
           "  -T, --time=NUM           duration of benchmark test in seconds\n"
           "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
           "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
           "  --log-prefix=PREFIX      prefix for transaction time log file\n"
           "                           (default: \"pgbench_log\")\n"
           "  --progress-timestamp     use Unix epoch timestamps for progress\n"
           "  --random-seed=SEED       set random seed (\"time\", \"rand\", integer)\n"
           "  --sampling-rate=NUM      fraction of transactions to log (e.g., 0.01 for 1%%)\n"
           "  --show-script=NAME       show builtin script code, then exit\n"
           "\nCommon options:\n"
           "  -d, --debug              print debugging output\n"
           "  -h, --host=HOSTNAME      database server host or socket directory\n"
           "  -p, --port=PORT          database server port number\n"
           "  -U, --username=USERNAME  connect as specified database user\n"
           "  -V, --version            output version information, then exit\n"
           "  -?, --help               show this help, then exit\n"
           "\n"
           "Report bugs to <pgsql-bugs@lists.postgresql.org>.\n",
           progname, progname);
}

/* return whether str matches "^\s*[-+]?[0-9]+$" */
static bool
is_an_int(const char *str)
{
    const char *ptr = str;

    /* skip leading spaces; cast is consistent with strtoint64 */
    while (*ptr && isspace((unsigned char) *ptr))
        ptr++;

    /* skip sign */
    if (*ptr == '+' || *ptr == '-')
        ptr++;

    /* at least one digit */
    if (*ptr && !isdigit((unsigned char) *ptr))
        return false;

    /* eat all digits */
    while (*ptr && isdigit((unsigned char) *ptr))
        ptr++;

    /* must have reached end of string */
    return *ptr == '\0';
}


/*
 * strtoint64 -- convert a string to 64-bit integer
 *
 * This function is a slightly modified version of scanint8() from
 * src/backend/utils/adt/int8.c.
 *
 * The function returns whether the conversion worked, and if so
 * "*result" is set to the result.
 *
 * If not errorOK, an error message is also printed out on errors.
 */
bool
strtoint64(const char *str, bool errorOK, int64 *result)
{
    const char *ptr = str;
    int64       tmp = 0;
    bool        neg = false;

    /*
     * Do our own scan, rather than relying on sscanf which might be broken
     * for long long.
     *
     * As INT64_MIN can't be stored as a positive 64 bit integer, accumulate
     * value as a negative number.
     */

    /* skip leading spaces */
    while (*ptr && isspace((unsigned char) *ptr))
        ptr++;

    /* handle sign */
    if (*ptr == '-')
    {
        ptr++;
        neg = true;
    }
    else if (*ptr == '+')
        ptr++;

    /* require at least one digit */
    if (unlikely(!isdigit((unsigned char) *ptr)))
        goto invalid_syntax;

    /* process digits */
    while (*ptr && isdigit((unsigned char) *ptr))
    {
        int8        digit = (*ptr++ - '0');

        if (unlikely(pg_mul_s64_overflow(tmp, 10, &tmp)) ||
            unlikely(pg_sub_s64_overflow(tmp, digit, &tmp)))
            goto out_of_range;
    }

    /* allow trailing whitespace, but not other trailing chars */
    while (*ptr != '\0' && isspace((unsigned char) *ptr))
        ptr++;

    if (unlikely(*ptr != '\0'))
        goto invalid_syntax;

    if (!neg)
    {
        if (unlikely(tmp == PG_INT64_MIN))
            goto out_of_range;
        tmp = -tmp;
    }

    *result = tmp;
    return true;

out_of_range:
    if (!errorOK)
        fprintf(stderr,
                "value \"%s\" is out of range for type bigint\n", str);
    return false;

invalid_syntax:
    if (!errorOK)
        fprintf(stderr,
                "invalid input syntax for type bigint: \"%s\"\n", str);
    return false;
}

/* convert string to double, detecting overflows/underflows */
bool
strtodouble(const char *str, bool errorOK, double *dv)
{
    char       *end;

    errno = 0;
    *dv = strtod(str, &end);

    if (unlikely(errno != 0))
    {
        if (!errorOK)
            fprintf(stderr,
                    "value \"%s\" is out of range for type double\n", str);
        return false;
    }

    if (unlikely(end == str || *end != '\0'))
    {
        if (!errorOK)
            fprintf(stderr,
                    "invalid input syntax for type double: \"%s\"\n", str);
        return false;
    }
    return true;
}

/*
 * Initialize a random state struct.
 *
 * We derive the seed from base_random_sequence, which must be set up already.
 */
static void
initRandomState(RandomState *random_state)
{
    random_state->xseed[0] = (unsigned short)
        (pg_jrand48(base_random_sequence.xseed) & 0xFFFF);
    random_state->xseed[1] = (unsigned short)
        (pg_jrand48(base_random_sequence.xseed) & 0xFFFF);
    random_state->xseed[2] = (unsigned short)
        (pg_jrand48(base_random_sequence.xseed) & 0xFFFF);
}

/*
 * Random number generator: uniform distribution from min to max inclusive.
 *
 * Although the limits are expressed as int64, you can't generate the full
 * int64 range in one call, because the difference of the limits mustn't
 * overflow int64.  In practice it's unwise to ask for more than an int32
 * range, because of the limited precision of pg_erand48().
 */
static int64
getrand(RandomState *random_state, int64 min, int64 max)
{
    /*
     * Odd coding is so that min and max have approximately the same chance of
     * being selected as do numbers between them.
     *
     * pg_erand48() is thread-safe and concurrent, which is why we use it
     * rather than random(), which in glibc is non-reentrant, and therefore
     * protected by a mutex, and therefore a bottleneck on machines with many
     * CPUs.
     */
    return min + (int64) ((max - min + 1) * pg_erand48(random_state->xseed));
}

/*
 * random number generator: exponential distribution from min to max inclusive.
 * the parameter is so that the density of probability for the last cut-off max
 * value is exp(-parameter).
 */
static int64
getExponentialRand(RandomState *random_state, int64 min, int64 max,
                   double parameter)
{
    double      cut,
                uniform,
                rand;

    /* abort if wrong parameter, but must really be checked beforehand */
    Assert(parameter > 0.0);
    cut = exp(-parameter);
    /* erand in [0, 1), uniform in (0, 1] */
    uniform = 1.0 - pg_erand48(random_state->xseed);

    /*
     * inner expression in (cut, 1] (if parameter > 0), rand in [0, 1)
     */
    Assert((1.0 - cut) != 0.0);
    rand = -log(cut + (1.0 - cut) * uniform) / parameter;
    /* return int64 random number within between min and max */
    return min + (int64) ((max - min + 1) * rand);
}

/* random number generator: gaussian distribution from min to max inclusive */
static int64
getGaussianRand(RandomState *random_state, int64 min, int64 max,
                double parameter)
{
    double      stdev;
    double      rand;

    /* abort if parameter is too low, but must really be checked beforehand */
    Assert(parameter >= MIN_GAUSSIAN_PARAM);

    /*
     * Get user specified random number from this loop, with -parameter <
     * stdev <= parameter
     *
     * This loop is executed until the number is in the expected range.
     *
     * As the minimum parameter is 2.0, the probability of looping is low:
     * sqrt(-2 ln(r)) <= 2 => r >= e^{-2} ~ 0.135, then when taking the
     * average sinus multiplier as 2/pi, we have a 8.6% looping probability in
     * the worst case. For a parameter value of 5.0, the looping probability
     * is about e^{-5} * 2 / pi ~ 0.43%.
     */
    do
    {
        /*
         * pg_erand48 generates [0,1), but for the basic version of the
         * Box-Muller transform the two uniformly distributed random numbers
         * are expected in (0, 1] (see
         * https://en.wikipedia.org/wiki/Box-Muller_transform)
         */
        double      rand1 = 1.0 - pg_erand48(random_state->xseed);
        double      rand2 = 1.0 - pg_erand48(random_state->xseed);

        /* Box-Muller basic form transform */
        double      var_sqrt = sqrt(-2.0 * log(rand1));

        stdev = var_sqrt * sin(2.0 * M_PI * rand2);

        /*
         * we may try with cos, but there may be a bias induced if the
         * previous value fails the test. To be on the safe side, let us try
         * over.
         */
    }
    while (stdev < -parameter || stdev >= parameter);

    /* stdev is in [-parameter, parameter), normalization to [0,1) */
    rand = (stdev + parameter) / (parameter * 2.0);

    /* return int64 random number within between min and max */
    return min + (int64) ((max - min + 1) * rand);
}

/*
 * random number generator: generate a value, such that the series of values
 * will approximate a Poisson distribution centered on the given value.
 *
 * Individual results are rounded to integers, though the center value need
 * not be one.
 */
static int64
getPoissonRand(RandomState *random_state, double center)
{
    /*
     * Use inverse transform sampling to generate a value > 0, such that the
     * expected (i.e. average) value is the given argument.
     */
    double      uniform;

    /* erand in [0, 1), uniform in (0, 1] */
    uniform = 1.0 - pg_erand48(random_state->xseed);

    return (int64) (-log(uniform) * center + 0.5);
}

/*
 * Computing zipfian using rejection method, based on
 * "Non-Uniform Random Variate Generation",
 * Luc Devroye, p. 550-551, Springer 1986.
 *
 * This works for s > 1.0, but may perform badly for s very close to 1.0.
 */
static int64
computeIterativeZipfian(RandomState *random_state, int64 n, double s)
{
    double      b = pow(2.0, s - 1.0);
    double      x,
                t,
                u,
                v;

    /* Ensure n is sane */
    if (n <= 1)
        return 1;

    while (true)
    {
        /* random variates */
        u = pg_erand48(random_state->xseed);
        v = pg_erand48(random_state->xseed);

        x = floor(pow(u, -1.0 / (s - 1.0)));

        t = pow(1.0 + 1.0 / x, s - 1.0);
        /* reject if too large or out of bound */
        if (v * x * (t - 1.0) / (b - 1.0) <= t / b && x <= n)
            break;
    }
    return (int64) x;
}

/* random number generator: zipfian distribution from min to max inclusive */
static int64
getZipfianRand(RandomState *random_state, int64 min, int64 max, double s)
{
    int64       n = max - min + 1;

    /* abort if parameter is invalid */
    Assert(MIN_ZIPFIAN_PARAM <= s && s <= MAX_ZIPFIAN_PARAM);

    return min - 1 + computeIterativeZipfian(random_state, n, s);
}

/*
 * FNV-1a hash function
 */
static int64
getHashFnv1a(int64 val, uint64 seed)
{
    int64       result;
    int         i;

    result = FNV_OFFSET_BASIS ^ seed;
    for (i = 0; i < 8; ++i)
    {
        int32       octet = val & 0xff;

        val = val >> 8;
        result = result ^ octet;
        result = result * FNV_PRIME;
    }

    return result;
}

/*
 * Murmur2 hash function
 *
 * Based on original work of Austin Appleby
 * https://github.com/aappleby/smhasher/blob/master/src/MurmurHash2.cpp
 */
static int64
getHashMurmur2(int64 val, uint64 seed)
{
    uint64      result = seed ^ MM2_MUL_TIMES_8;    /* sizeof(int64) */
    uint64      k = (uint64) val;

    k *= MM2_MUL;
    k ^= k >> MM2_ROT;
    k *= MM2_MUL;

    result ^= k;
    result *= MM2_MUL;

    result ^= result >> MM2_ROT;
    result *= MM2_MUL;
    result ^= result >> MM2_ROT;

    return (int64) result;
}

/*
 * Initialize the given SimpleStats struct to all zeroes
 */
static void
initSimpleStats(SimpleStats *ss)
{
    memset(ss, 0, sizeof(SimpleStats));
}

/*
 * Accumulate one value into a SimpleStats struct.
 */
static void
addToSimpleStats(SimpleStats *ss, double val)
{
    if (ss->count == 0 || val < ss->min)
        ss->min = val;
    if (ss->count == 0 || val > ss->max)
        ss->max = val;
    ss->count++;
    ss->sum += val;
    ss->sum2 += val * val;
}

/*
 * Merge two SimpleStats objects
 */
static void
mergeSimpleStats(SimpleStats *acc, SimpleStats *ss)
{
    if (acc->count == 0 || ss->min < acc->min)
        acc->min = ss->min;
    if (acc->count == 0 || ss->max > acc->max)
        acc->max = ss->max;
    acc->count += ss->count;
    acc->sum += ss->sum;
    acc->sum2 += ss->sum2;
}

/*
 * Initialize a StatsData struct to mostly zeroes, with its start time set to
 * the given value.
 */
static void
initStats(StatsData *sd, time_t start_time)
{
    sd->start_time = start_time;
    sd->cnt = 0;
    sd->skipped = 0;
    initSimpleStats(&sd->latency);
    initSimpleStats(&sd->lag);
}

/*
 * Accumulate one additional item into the given stats object.
 */
static void
accumStats(StatsData *stats, bool skipped, double lat, double lag)
{
    stats->cnt++;

    if (skipped)
    {
        /* no latency to record on skipped transactions */
        stats->skipped++;
    }
    else
    {
        addToSimpleStats(&stats->latency, lat);

        /* and possibly the same for schedule lag */
        if (throttle_delay)
            addToSimpleStats(&stats->lag, lag);
    }
}

/* call PQexec() and exit() on failure */
static void
executeStatement(PGconn *con, const char *sql)
{
    PGresult   *res;

    res = PQexec(con, sql);
    if (PQresultStatus(res) != PGRES_COMMAND_OK)
    {
        fprintf(stderr, "%s", PQerrorMessage(con));
        exit(1);
    }
    PQclear(res);
}

/* call PQexec() and complain, but without exiting, on failure */
static void
tryExecuteStatement(PGconn *con, const char *sql)
{
    PGresult   *res;

    res = PQexec(con, sql);
    if (PQresultStatus(res) != PGRES_COMMAND_OK)
    {
        fprintf(stderr, "%s", PQerrorMessage(con));
        fprintf(stderr, "(ignoring this error and continuing anyway)\n");
    }
    PQclear(res);
}

/* set up a connection to the backend */
static PGconn *
doConnect(void)
{
    PGconn     *conn;
    bool        new_pass;
    static bool have_password = false;
    static char password[100];

    /*
     * Start the connection.  Loop until we have a password if requested by
     * backend.
     */
    do
    {
#define PARAMS_ARRAY_SIZE   7

        const char *keywords[PARAMS_ARRAY_SIZE];
        const char *values[PARAMS_ARRAY_SIZE];

        keywords[0] = "host";
        values[0] = pghost;
        keywords[1] = "port";
        values[1] = pgport;
        keywords[2] = "user";
        values[2] = login;
        keywords[3] = "password";
        values[3] = have_password ? password : NULL;
        keywords[4] = "dbname";
        values[4] = dbName;
        keywords[5] = "fallback_application_name";
        values[5] = progname;
        keywords[6] = NULL;
        values[6] = NULL;

        new_pass = false;

        conn = PQconnectdbParams(keywords, values, true);

        if (!conn)
        {
            fprintf(stderr, "connection to database \"%s\" failed\n",
                    dbName);
            return NULL;
        }

        if (PQstatus(conn) == CONNECTION_BAD &&
            PQconnectionNeedsPassword(conn) &&
            !have_password)
        {
            PQfinish(conn);
            simple_prompt("Password: ", password, sizeof(password), false);
            have_password = true;
            new_pass = true;
        }
    } while (new_pass);

    /* check to see that the backend connection was successfully made */
    if (PQstatus(conn) == CONNECTION_BAD)
    {
        fprintf(stderr, "connection to database \"%s\" failed:\n%s",
                dbName, PQerrorMessage(conn));
        PQfinish(conn);
        return NULL;
    }

    return conn;
}

/* qsort comparator for Variable array */
static int
compareVariableNames(const void *v1, const void *v2)
{
    return strcmp(((const Variable *) v1)->name,
                  ((const Variable *) v2)->name);
}

/* Locate a variable by name; returns NULL if unknown */
static Variable *
lookupVariable(CState *st, char *name)
{
    Variable    key;

    /* On some versions of Solaris, bsearch of zero items dumps core */
    if (st->nvariables <= 0)
        return NULL;

    /* Sort if we have to */
    if (!st->vars_sorted)
    {
        qsort((void *) st->variables, st->nvariables, sizeof(Variable),
              compareVariableNames);
        st->vars_sorted = true;
    }

    /* Now we can search */
    key.name = name;
    return (Variable *) bsearch((void *) &key,
                                (void *) st->variables,
                                st->nvariables,
                                sizeof(Variable),
                                compareVariableNames);
}

/* Get the value of a variable, in string form; returns NULL if unknown */
static char *
getVariable(CState *st, char *name)
{
    Variable   *var;
    char        stringform[64];

    var = lookupVariable(st, name);
    if (var == NULL)
        return NULL;            /* not found */

    if (var->svalue)
        return var->svalue;     /* we have it in string form */

    /* We need to produce a string equivalent of the value */
    Assert(var->value.type != PGBT_NO_VALUE);
    if (var->value.type == PGBT_NULL)
        snprintf(stringform, sizeof(stringform), "NULL");
    else if (var->value.type == PGBT_BOOLEAN)
        snprintf(stringform, sizeof(stringform),
                 "%s", var->value.u.bval ? "true" : "false");
    else if (var->value.type == PGBT_INT)
        snprintf(stringform, sizeof(stringform),
                 INT64_FORMAT, var->value.u.ival);
    else if (var->value.type == PGBT_DOUBLE)
        snprintf(stringform, sizeof(stringform),
                 "%.*g", DBL_DIG, var->value.u.dval);
    else                        /* internal error, unexpected type */
        Assert(0);
    var->svalue = pg_strdup(stringform);
    return var->svalue;
}

/* Try to convert variable to a value; return false on failure */
static bool
makeVariableValue(Variable *var)
{
    size_t      slen;

    if (var->value.type != PGBT_NO_VALUE)
        return true;            /* no work */

    slen = strlen(var->svalue);

    if (slen == 0)
        /* what should it do on ""? */
        return false;

    if (pg_strcasecmp(var->svalue, "null") == 0)
    {
        setNullValue(&var->value);
    }

    /*
     * accept prefixes such as y, ye, n, no... but not for "o". 0/1 are
     * recognized later as an int, which is converted to bool if needed.
     */
    else if (pg_strncasecmp(var->svalue, "true", slen) == 0 ||
             pg_strncasecmp(var->svalue, "yes", slen) == 0 ||
             pg_strcasecmp(var->svalue, "on") == 0)
    {
        setBoolValue(&var->value, true);
    }
    else if (pg_strncasecmp(var->svalue, "false", slen) == 0 ||
             pg_strncasecmp(var->svalue, "no", slen) == 0 ||
             pg_strcasecmp(var->svalue, "off") == 0 ||
             pg_strcasecmp(var->svalue, "of") == 0)
    {
        setBoolValue(&var->value, false);
    }
    else if (is_an_int(var->svalue))
    {
        /* if it looks like an int, it must be an int without overflow */
        int64       iv;

        if (!strtoint64(var->svalue, false, &iv))
            return false;

        setIntValue(&var->value, iv);
    }
    else                        /* type should be double */
    {
        double      dv;

        if (!strtodouble(var->svalue, true, &dv))
        {
            fprintf(stderr,
                    "malformed variable \"%s\" value: \"%s\"\n",
                    var->name, var->svalue);
            return false;
        }
        setDoubleValue(&var->value, dv);
    }
    return true;
}

/*
 * Check whether a variable's name is allowed.
 *
 * We allow any non-ASCII character, as well as ASCII letters, digits, and
 * underscore.
 *
 * Keep this in sync with the definitions of variable name characters in
 * "src/fe_utils/psqlscan.l", "src/bin/psql/psqlscanslash.l" and
 * "src/bin/pgbench/exprscan.l".  Also see parseVariable(), below.
 *
 * Note: this static function is copied from "src/bin/psql/variables.c"
 */
static bool
valid_variable_name(const char *name)
{
    const unsigned char *ptr = (const unsigned char *) name;

    /* Mustn't be zero-length */
    if (*ptr == '\0')
        return false;

    while (*ptr)
    {
        if (IS_HIGHBIT_SET(*ptr) ||
            strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"
                   "_0123456789", *ptr) != NULL)
            ptr++;
        else
            return false;
    }

    return true;
}

/*
 * Lookup a variable by name, creating it if need be.
 * Caller is expected to assign a value to the variable.
 * Returns NULL on failure (bad name).
 */
static Variable *
lookupCreateVariable(CState *st, const char *context, char *name)
{
    Variable   *var;

    var = lookupVariable(st, name);
    if (var == NULL)
    {
        Variable   *newvars;

        /*
         * Check for the name only when declaring a new variable to avoid
         * overhead.
         */
        if (!valid_variable_name(name))
        {
            fprintf(stderr, "%s: invalid variable name: \"%s\"\n",
                    context, name);
            return NULL;
        }

        /* Create variable at the end of the array */
        if (st->variables)
            newvars = (Variable *) pg_realloc(st->variables,
                                              (st->nvariables + 1) * sizeof(Variable));
        else
            newvars = (Variable *) pg_malloc(sizeof(Variable));

        st->variables = newvars;

        var = &newvars[st->nvariables];

        var->name = pg_strdup(name);
        var->svalue = NULL;
        /* caller is expected to initialize remaining fields */

        st->nvariables++;
        /* we don't re-sort the array till we have to */
        st->vars_sorted = false;
    }

    return var;
}

/* Assign a string value to a variable, creating it if need be */
/* Returns false on failure (bad name) */
static bool
putVariable(CState *st, const char *context, char *name, const char *value)
{
    Variable   *var;
    char       *val;

    var = lookupCreateVariable(st, context, name);
    if (!var)
        return false;

    /* dup then free, in case value is pointing at this variable */
    val = pg_strdup(value);

    if (var->svalue)
        free(var->svalue);
    var->svalue = val;
    var->value.type = PGBT_NO_VALUE;

    return true;
}

/* Assign a value to a variable, creating it if need be */
/* Returns false on failure (bad name) */
static bool
putVariableValue(CState *st, const char *context, char *name,
                 const PgBenchValue *value)
{
    Variable   *var;

    var = lookupCreateVariable(st, context, name);
    if (!var)
        return false;

    if (var->svalue)
        free(var->svalue);
    var->svalue = NULL;
    var->value = *value;

    return true;
}

/* Assign an integer value to a variable, creating it if need be */
/* Returns false on failure (bad name) */
static bool
putVariableInt(CState *st, const char *context, char *name, int64 value)
{
    PgBenchValue val;

    setIntValue(&val, value);
    return putVariableValue(st, context, name, &val);
}

/*
 * Parse a possible variable reference (:varname).
 *
 * "sql" points at a colon.  If what follows it looks like a valid
 * variable name, return a malloc'd string containing the variable name,
 * and set *eaten to the number of characters consumed.
 * Otherwise, return NULL.
 */
static char *
parseVariable(const char *sql, int *eaten)
{
    int         i = 0;
    char       *name;

    do
    {
        i++;
    } while (IS_HIGHBIT_SET(sql[i]) ||
             strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"
                    "_0123456789", sql[i]) != NULL);
    if (i == 1)
        return NULL;            /* no valid variable name chars */

    name = pg_malloc(i);
    memcpy(name, &sql[1], i - 1);
    name[i - 1] = '\0';

    *eaten = i;
    return name;
}

static char *
replaceVariable(char **sql, char *param, int len, char *value)
{
    int         valueln = strlen(value);

    if (valueln > len)
    {
        size_t      offset = param - *sql;

        *sql = pg_realloc(*sql, strlen(*sql) - len + valueln + 1);
        param = *sql + offset;
    }

    if (valueln != len)
        memmove(param + valueln, param + len, strlen(param + len) + 1);
    memcpy(param, value, valueln);

    return param + valueln;
}

static char *
assignVariables(CState *st, char *sql)
{
    char       *p,
               *name,
               *val;

    p = sql;
    while ((p = strchr(p, ':')) != NULL)
    {
        int         eaten;

        name = parseVariable(p, &eaten);
        if (name == NULL)
        {
            while (*p == ':')
            {
                p++;
            }
            continue;
        }

        val = getVariable(st, name);
        free(name);
        if (val == NULL)
        {
            p++;
            continue;
        }

        p = replaceVariable(&sql, p, eaten, val);
    }

    return sql;
}

static void
getQueryParams(CState *st, const Command *command, const char **params)
{
    int         i;

    for (i = 0; i < command->argc - 1; i++)
        params[i] = getVariable(st, command->argv[i + 1]);
}

static char *
valueTypeName(PgBenchValue *pval)
{
    if (pval->type == PGBT_NO_VALUE)
        return "none";
    else if (pval->type == PGBT_NULL)
        return "null";
    else if (pval->type == PGBT_INT)
        return "int";
    else if (pval->type == PGBT_DOUBLE)
        return "double";
    else if (pval->type == PGBT_BOOLEAN)
        return "boolean";
    else
    {
        /* internal error, should never get there */
        Assert(false);
        return NULL;
    }
}

/* get a value as a boolean, or tell if there is a problem */
static bool
coerceToBool(PgBenchValue *pval, bool *bval)
{
    if (pval->type == PGBT_BOOLEAN)
    {
        *bval = pval->u.bval;
        return true;
    }
    else                        /* NULL, INT or DOUBLE */
    {
        fprintf(stderr, "cannot coerce %s to boolean\n", valueTypeName(pval));
        *bval = false;          /* suppress uninitialized-variable warnings */
        return false;
    }
}

/*
 * Return true or false from an expression for conditional purposes.
 * Non zero numerical values are true, zero and NULL are false.
 */
static bool
valueTruth(PgBenchValue *pval)
{
    switch (pval->type)
    {
        case PGBT_NULL:
            return false;
        case PGBT_BOOLEAN:
            return pval->u.bval;
        case PGBT_INT:
            return pval->u.ival != 0;
        case PGBT_DOUBLE:
            return pval->u.dval != 0.0;
        default:
            /* internal error, unexpected type */
            Assert(0);
            return false;
    }
}

/* get a value as an int, tell if there is a problem */
static bool
coerceToInt(PgBenchValue *pval, int64 *ival)
{
    if (pval->type == PGBT_INT)
    {
        *ival = pval->u.ival;
        return true;
    }
    else if (pval->type == PGBT_DOUBLE)
    {
        double      dval = rint(pval->u.dval);

        if (isnan(dval) || !FLOAT8_FITS_IN_INT64(dval))
        {
            fprintf(stderr, "double to int overflow for %f\n", dval);
            return false;
        }
        *ival = (int64) dval;
        return true;
    }
    else                        /* BOOLEAN or NULL */
    {
        fprintf(stderr, "cannot coerce %s to int\n", valueTypeName(pval));
        return false;
    }
}

/* get a value as a double, or tell if there is a problem */
static bool
coerceToDouble(PgBenchValue *pval, double *dval)
{
    if (pval->type == PGBT_DOUBLE)
    {
        *dval = pval->u.dval;
        return true;
    }
    else if (pval->type == PGBT_INT)
    {
        *dval = (double) pval->u.ival;
        return true;
    }
    else                        /* BOOLEAN or NULL */
    {
        fprintf(stderr, "cannot coerce %s to double\n", valueTypeName(pval));
        return false;
    }
}

/* assign a null value */
static void
setNullValue(PgBenchValue *pv)
{
    pv->type = PGBT_NULL;
    pv->u.ival = 0;
}

/* assign a boolean value */
static void
setBoolValue(PgBenchValue *pv, bool bval)
{
    pv->type = PGBT_BOOLEAN;
    pv->u.bval = bval;
}

/* assign an integer value */
static void
setIntValue(PgBenchValue *pv, int64 ival)
{
    pv->type = PGBT_INT;
    pv->u.ival = ival;
}

/* assign a double value */
static void
setDoubleValue(PgBenchValue *pv, double dval)
{
    pv->type = PGBT_DOUBLE;
    pv->u.dval = dval;
}

static bool
isLazyFunc(PgBenchFunction func)
{
    return func == PGBENCH_AND || func == PGBENCH_OR || func == PGBENCH_CASE;
}

/* lazy evaluation of some functions */
static bool
evalLazyFunc(CState *st,
             PgBenchFunction func, PgBenchExprLink *args, PgBenchValue *retval)
{
    PgBenchValue a1,
                a2;
    bool        ba1,
                ba2;

    Assert(isLazyFunc(func) && args != NULL && args->next != NULL);

    /* args points to first condition */
    if (!evaluateExpr(st, args->expr, &a1))
        return false;

    /* second condition for AND/OR and corresponding branch for CASE */
    args = args->next;

    switch (func)
    {
        case PGBENCH_AND:
            if (a1.type == PGBT_NULL)
            {
                setNullValue(retval);
                return true;
            }

            if (!coerceToBool(&a1, &ba1))
                return false;

            if (!ba1)
            {
                setBoolValue(retval, false);
                return true;
            }

            if (!evaluateExpr(st, args->expr, &a2))
                return false;

            if (a2.type == PGBT_NULL)
            {
                setNullValue(retval);
                return true;
            }
            else if (!coerceToBool(&a2, &ba2))
                return false;
            else
            {
                setBoolValue(retval, ba2);
                return true;
            }

            return true;

        case PGBENCH_OR:

            if (a1.type == PGBT_NULL)
            {
                setNullValue(retval);
                return true;
            }

            if (!coerceToBool(&a1, &ba1))
                return false;

            if (ba1)
            {
                setBoolValue(retval, true);
                return true;
            }

            if (!evaluateExpr(st, args->expr, &a2))
                return false;

            if (a2.type == PGBT_NULL)
            {
                setNullValue(retval);
                return true;
            }
            else if (!coerceToBool(&a2, &ba2))
                return false;
            else
            {
                setBoolValue(retval, ba2);
                return true;
            }

        case PGBENCH_CASE:
            /* when true, execute branch */
            if (valueTruth(&a1))
                return evaluateExpr(st, args->expr, retval);

            /* now args contains next condition or final else expression */
            args = args->next;

            /* final else case? */
            if (args->next == NULL)
                return evaluateExpr(st, args->expr, retval);

            /* no, another when, proceed */
            return evalLazyFunc(st, PGBENCH_CASE, args, retval);

        default:
            /* internal error, cannot get here */
            Assert(0);
            break;
    }
    return false;
}

/* maximum number of function arguments */
#define MAX_FARGS 16

/*
 * Recursive evaluation of standard functions,
 * which do not require lazy evaluation.
 */
static bool
evalStandardFunc(CState *st,
                 PgBenchFunction func, PgBenchExprLink *args,
                 PgBenchValue *retval)
{
    /* evaluate all function arguments */
    int         nargs = 0;
    PgBenchValue vargs[MAX_FARGS];
    PgBenchExprLink *l = args;
    bool        has_null = false;

    for (nargs = 0; nargs < MAX_FARGS && l != NULL; nargs++, l = l->next)
    {
        if (!evaluateExpr(st, l->expr, &vargs[nargs]))
            return false;
        has_null |= vargs[nargs].type == PGBT_NULL;
    }

    if (l != NULL)
    {
        fprintf(stderr,
                "too many function arguments, maximum is %d\n", MAX_FARGS);
        return false;
    }

    /* NULL arguments */
    if (has_null && func != PGBENCH_IS && func != PGBENCH_DEBUG)
    {
        setNullValue(retval);
        return true;
    }

    /* then evaluate function */
    switch (func)
    {
            /* overloaded operators */
        case PGBENCH_ADD:
        case PGBENCH_SUB:
        case PGBENCH_MUL:
        case PGBENCH_DIV:
        case PGBENCH_MOD:
        case PGBENCH_EQ:
        case PGBENCH_NE:
        case PGBENCH_LE:
        case PGBENCH_LT:
            {
                PgBenchValue *lval = &vargs[0],
                           *rval = &vargs[1];

                Assert(nargs == 2);

                /* overloaded type management, double if some double */
                if ((lval->type == PGBT_DOUBLE ||
                     rval->type == PGBT_DOUBLE) && func != PGBENCH_MOD)
                {
                    double      ld,
                                rd;

                    if (!coerceToDouble(lval, &ld) ||
                        !coerceToDouble(rval, &rd))
                        return false;

                    switch (func)
                    {
                        case PGBENCH_ADD:
                            setDoubleValue(retval, ld + rd);
                            return true;

                        case PGBENCH_SUB:
                            setDoubleValue(retval, ld - rd);
                            return true;

                        case PGBENCH_MUL:
                            setDoubleValue(retval, ld * rd);
                            return true;

                        case PGBENCH_DIV:
                            setDoubleValue(retval, ld / rd);
                            return true;

                        case PGBENCH_EQ:
                            setBoolValue(retval, ld == rd);
                            return true;

                        case PGBENCH_NE:
                            setBoolValue(retval, ld != rd);
                            return true;

                        case PGBENCH_LE:
                            setBoolValue(retval, ld <= rd);
                            return true;

                        case PGBENCH_LT:
                            setBoolValue(retval, ld < rd);
                            return true;

                        default:
                            /* cannot get here */
                            Assert(0);
                    }
                }
                else            /* we have integer operands, or % */
                {
                    int64       li,
                                ri,
                                res;

                    if (!coerceToInt(lval, &li) ||
                        !coerceToInt(rval, &ri))
                        return false;

                    switch (func)
                    {
                        case PGBENCH_ADD:
                            if (pg_add_s64_overflow(li, ri, &res))
                            {
                                fprintf(stderr, "bigint add out of range\n");
                                return false;
                            }
                            setIntValue(retval, res);
                            return true;

                        case PGBENCH_SUB:
                            if (pg_sub_s64_overflow(li, ri, &res))
                            {
                                fprintf(stderr, "bigint sub out of range\n");
                                return false;
                            }
                            setIntValue(retval, res);
                            return true;

                        case PGBENCH_MUL:
                            if (pg_mul_s64_overflow(li, ri, &res))
                            {
                                fprintf(stderr, "bigint mul out of range\n");
                                return false;
                            }
                            setIntValue(retval, res);
                            return true;

                        case PGBENCH_EQ:
                            setBoolValue(retval, li == ri);
                            return true;

                        case PGBENCH_NE:
                            setBoolValue(retval, li != ri);
                            return true;

                        case PGBENCH_LE:
                            setBoolValue(retval, li <= ri);
                            return true;

                        case PGBENCH_LT:
                            setBoolValue(retval, li < ri);
                            return true;

                        case PGBENCH_DIV:
                        case PGBENCH_MOD:
                            if (ri == 0)
                            {
                                fprintf(stderr, "division by zero\n");
                                return false;
                            }
                            /* special handling of -1 divisor */
                            if (ri == -1)
                            {
                                if (func == PGBENCH_DIV)
                                {
                                    /* overflow check (needed for INT64_MIN) */
                                    if (li == PG_INT64_MIN)
                                    {
                                        fprintf(stderr, "bigint div out of range\n");
                                        return false;
                                    }
                                    else
                                        setIntValue(retval, -li);
                                }
                                else
                                    setIntValue(retval, 0);
                                return true;
                            }
                            /* else divisor is not -1 */
                            if (func == PGBENCH_DIV)
                                setIntValue(retval, li / ri);
                            else    /* func == PGBENCH_MOD */
                                setIntValue(retval, li % ri);

                            return true;

                        default:
                            /* cannot get here */
                            Assert(0);
                    }
                }

                Assert(0);
                return false;   /* NOTREACHED */
            }

            /* integer bitwise operators */
        case PGBENCH_BITAND:
        case PGBENCH_BITOR:
        case PGBENCH_BITXOR:
        case PGBENCH_LSHIFT:
        case PGBENCH_RSHIFT:
            {
                int64       li,
                            ri;

                if (!coerceToInt(&vargs[0], &li) || !coerceToInt(&vargs[1], &ri))
                    return false;

                if (func == PGBENCH_BITAND)
                    setIntValue(retval, li & ri);
                else if (func == PGBENCH_BITOR)
                    setIntValue(retval, li | ri);
                else if (func == PGBENCH_BITXOR)
                    setIntValue(retval, li ^ ri);
                else if (func == PGBENCH_LSHIFT)
                    setIntValue(retval, li << ri);
                else if (func == PGBENCH_RSHIFT)
                    setIntValue(retval, li >> ri);
                else            /* cannot get here */
                    Assert(0);

                return true;
            }

            /* logical operators */
        case PGBENCH_NOT:
            {
                bool        b;

                if (!coerceToBool(&vargs[0], &b))
                    return false;

                setBoolValue(retval, !b);
                return true;
            }

            /* no arguments */
        case PGBENCH_PI:
            setDoubleValue(retval, M_PI);
            return true;

            /* 1 overloaded argument */
        case PGBENCH_ABS:
            {
                PgBenchValue *varg = &vargs[0];

                Assert(nargs == 1);

                if (varg->type == PGBT_INT)
                {
                    int64       i = varg->u.ival;

                    setIntValue(retval, i < 0 ? -i : i);
                }
                else
                {
                    double      d = varg->u.dval;

                    Assert(varg->type == PGBT_DOUBLE);
                    setDoubleValue(retval, d < 0.0 ? -d : d);
                }

                return true;
            }

        case PGBENCH_DEBUG:
            {
                PgBenchValue *varg = &vargs[0];

                Assert(nargs == 1);

                fprintf(stderr, "debug(script=%d,command=%d): ",
                        st->use_file, st->command + 1);

                if (varg->type == PGBT_NULL)
                    fprintf(stderr, "null\n");
                else if (varg->type == PGBT_BOOLEAN)
                    fprintf(stderr, "boolean %s\n", varg->u.bval ? "true" : "false");
                else if (varg->type == PGBT_INT)
                    fprintf(stderr, "int " INT64_FORMAT "\n", varg->u.ival);
                else if (varg->type == PGBT_DOUBLE)
                    fprintf(stderr, "double %.*g\n", DBL_DIG, varg->u.dval);
                else            /* internal error, unexpected type */
                    Assert(0);

                *retval = *varg;

                return true;
            }

            /* 1 double argument */
        case PGBENCH_DOUBLE:
        case PGBENCH_SQRT:
        case PGBENCH_LN:
        case PGBENCH_EXP:
            {
                double      dval;

                Assert(nargs == 1);

                if (!coerceToDouble(&vargs[0], &dval))
                    return false;

                if (func == PGBENCH_SQRT)
                    dval = sqrt(dval);
                else if (func == PGBENCH_LN)
                    dval = log(dval);
                else if (func == PGBENCH_EXP)
                    dval = exp(dval);
                /* else is cast: do nothing */

                setDoubleValue(retval, dval);
                return true;
            }

            /* 1 int argument */
        case PGBENCH_INT:
            {
                int64       ival;

                Assert(nargs == 1);

                if (!coerceToInt(&vargs[0], &ival))
                    return false;

                setIntValue(retval, ival);
                return true;
            }

            /* variable number of arguments */
        case PGBENCH_LEAST:
        case PGBENCH_GREATEST:
            {
                bool        havedouble;
                int         i;

                Assert(nargs >= 1);

                /* need double result if any input is double */
                havedouble = false;
                for (i = 0; i < nargs; i++)
                {
                    if (vargs[i].type == PGBT_DOUBLE)
                    {
                        havedouble = true;
                        break;
                    }
                }
                if (havedouble)
                {
                    double      extremum;

                    if (!coerceToDouble(&vargs[0], &extremum))
                        return false;
                    for (i = 1; i < nargs; i++)
                    {
                        double      dval;

                        if (!coerceToDouble(&vargs[i], &dval))
                            return false;
                        if (func == PGBENCH_LEAST)
                            extremum = Min(extremum, dval);
                        else
                            extremum = Max(extremum, dval);
                    }
                    setDoubleValue(retval, extremum);
                }
                else
                {
                    int64       extremum;

                    if (!coerceToInt(&vargs[0], &extremum))
                        return false;
                    for (i = 1; i < nargs; i++)
                    {
                        int64       ival;

                        if (!coerceToInt(&vargs[i], &ival))
                            return false;
                        if (func == PGBENCH_LEAST)
                            extremum = Min(extremum, ival);
                        else
                            extremum = Max(extremum, ival);
                    }
                    setIntValue(retval, extremum);
                }
                return true;
            }

            /* random functions */
        case PGBENCH_RANDOM:
        case PGBENCH_RANDOM_EXPONENTIAL:
        case PGBENCH_RANDOM_GAUSSIAN:
        case PGBENCH_RANDOM_ZIPFIAN:
            {
                int64       imin,
                            imax;

                Assert(nargs >= 2);

                if (!coerceToInt(&vargs[0], &imin) ||
                    !coerceToInt(&vargs[1], &imax))
                    return false;

                /* check random range */
                if (imin > imax)
                {
                    fprintf(stderr, "empty range given to random\n");
                    return false;
                }
                else if (imax - imin < 0 || (imax - imin) + 1 < 0)
                {
                    /* prevent int overflows in random functions */
                    fprintf(stderr, "random range is too large\n");
                    return false;
                }

                if (func == PGBENCH_RANDOM)
                {
                    Assert(nargs == 2);
                    setIntValue(retval, getrand(&st->cs_func_rs, imin, imax));
                }
                else            /* gaussian & exponential */
                {
                    double      param;

                    Assert(nargs == 3);

                    if (!coerceToDouble(&vargs[2], &param))
                        return false;

                    if (func == PGBENCH_RANDOM_GAUSSIAN)
                    {
                        if (param < MIN_GAUSSIAN_PARAM)
                        {
                            fprintf(stderr,
                                    "gaussian parameter must be at least %f "
                                    "(not %f)\n", MIN_GAUSSIAN_PARAM, param);
                            return false;
                        }

                        setIntValue(retval,
                                    getGaussianRand(&st->cs_func_rs,
                                                    imin, imax, param));
                    }
                    else if (func == PGBENCH_RANDOM_ZIPFIAN)
                    {
                        if (param < MIN_ZIPFIAN_PARAM || param > MAX_ZIPFIAN_PARAM)
                        {
                            fprintf(stderr,
                                    "zipfian parameter must be in range [%.3f, %.0f]"
                                    " (not %f)\n",
                                    MIN_ZIPFIAN_PARAM, MAX_ZIPFIAN_PARAM, param);
                            return false;
                        }

                        setIntValue(retval,
                                    getZipfianRand(&st->cs_func_rs, imin, imax, param));
                    }
                    else        /* exponential */
                    {
                        if (param <= 0.0)
                        {
                            fprintf(stderr,
                                    "exponential parameter must be greater than zero"
                                    " (not %f)\n", param);
                            return false;
                        }

                        setIntValue(retval,
                                    getExponentialRand(&st->cs_func_rs,
                                                       imin, imax, param));
                    }
                }

                return true;
            }

        case PGBENCH_POW:
            {
                PgBenchValue *lval = &vargs[0];
                PgBenchValue *rval = &vargs[1];
                double      ld,
                            rd;

                Assert(nargs == 2);

                if (!coerceToDouble(lval, &ld) ||
                    !coerceToDouble(rval, &rd))
                    return false;

                setDoubleValue(retval, pow(ld, rd));

                return true;
            }

        case PGBENCH_IS:
            {
                Assert(nargs == 2);

                /*
                 * note: this simple implementation is more permissive than
                 * SQL
                 */
                setBoolValue(retval,
                             vargs[0].type == vargs[1].type &&
                             vargs[0].u.bval == vargs[1].u.bval);
                return true;
            }

            /* hashing */
        case PGBENCH_HASH_FNV1A:
        case PGBENCH_HASH_MURMUR2:
            {
                int64       val,
                            seed;

                Assert(nargs == 2);

                if (!coerceToInt(&vargs[0], &val) ||
                    !coerceToInt(&vargs[1], &seed))
                    return false;

                if (func == PGBENCH_HASH_MURMUR2)
                    setIntValue(retval, getHashMurmur2(val, seed));
                else if (func == PGBENCH_HASH_FNV1A)
                    setIntValue(retval, getHashFnv1a(val, seed));
                else
                    /* cannot get here */
                    Assert(0);

                return true;
            }

        default:
            /* cannot get here */
            Assert(0);
            /* dead code to avoid a compiler warning */
            return false;
    }
}

/* evaluate some function */
static bool
evalFunc(CState *st,
         PgBenchFunction func, PgBenchExprLink *args, PgBenchValue *retval)
{
    if (isLazyFunc(func))
        return evalLazyFunc(st, func, args, retval);
    else
        return evalStandardFunc(st, func, args, retval);
}

/*
 * Recursive evaluation of an expression in a pgbench script
 * using the current state of variables.
 * Returns whether the evaluation was ok,
 * the value itself is returned through the retval pointer.
 */
static bool
evaluateExpr(CState *st, PgBenchExpr *expr, PgBenchValue *retval)
{
    switch (expr->etype)
    {
        case ENODE_CONSTANT:
            {
                *retval = expr->u.constant;
                return true;
            }

        case ENODE_VARIABLE:
            {
                Variable   *var;

                if ((var = lookupVariable(st, expr->u.variable.varname)) == NULL)
                {
                    fprintf(stderr, "undefined variable \"%s\"\n",
                            expr->u.variable.varname);
                    return false;
                }

                if (!makeVariableValue(var))
                    return false;

                *retval = var->value;
                return true;
            }

        case ENODE_FUNCTION:
            return evalFunc(st,
                            expr->u.function.function,
                            expr->u.function.args,
                            retval);

        default:
            /* internal error which should never occur */
            fprintf(stderr, "unexpected enode type in evaluation: %d\n",
                    expr->etype);
            exit(1);
    }
}

/*
 * Convert command name to meta-command enum identifier
 */
static MetaCommand
getMetaCommand(const char *cmd)
{
    MetaCommand mc;

    if (cmd == NULL)
        mc = META_NONE;
    else if (pg_strcasecmp(cmd, "set") == 0)
        mc = META_SET;
    else if (pg_strcasecmp(cmd, "setshell") == 0)
        mc = META_SETSHELL;
    else if (pg_strcasecmp(cmd, "shell") == 0)
        mc = META_SHELL;
    else if (pg_strcasecmp(cmd, "sleep") == 0)
        mc = META_SLEEP;
    else if (pg_strcasecmp(cmd, "if") == 0)
        mc = META_IF;
    else if (pg_strcasecmp(cmd, "elif") == 0)
        mc = META_ELIF;
    else if (pg_strcasecmp(cmd, "else") == 0)
        mc = META_ELSE;
    else if (pg_strcasecmp(cmd, "endif") == 0)
        mc = META_ENDIF;
    else if (pg_strcasecmp(cmd, "gset") == 0)
        mc = META_GSET;
    else
        mc = META_NONE;
    return mc;
}

/*
 * Run a shell command. The result is assigned to the variable if not NULL.
 * Return true if succeeded, or false on error.
 */
static bool
runShellCommand(CState *st, char *variable, char **argv, int argc)
{
    char        command[SHELL_COMMAND_SIZE];
    int         i,
                len = 0;
    FILE       *fp;
    char        res[64];
    char       *endptr;
    int         retval;

    /*----------
     * Join arguments with whitespace separators. Arguments starting with
     * exactly one colon are treated as variables:
     *  name - append a string "name"
     *  :var - append a variable named 'var'
     *  ::name - append a string ":name"
     *----------
     */
    for (i = 0; i < argc; i++)
    {
        char       *arg;
        int         arglen;

        if (argv[i][0] != ':')
        {
            arg = argv[i];      /* a string literal */
        }
        else if (argv[i][1] == ':')
        {
            arg = argv[i] + 1;  /* a string literal starting with colons */
        }
        else if ((arg = getVariable(st, argv[i] + 1)) == NULL)
        {
            fprintf(stderr, "%s: undefined variable \"%s\"\n",
                    argv[0], argv[i]);
            return false;
        }

        arglen = strlen(arg);
        if (len + arglen + (i > 0 ? 1 : 0) >= SHELL_COMMAND_SIZE - 1)
        {
            fprintf(stderr, "%s: shell command is too long\n", argv[0]);
            return false;
        }

        if (i > 0)
            command[len++] = ' ';
        memcpy(command + len, arg, arglen);
        len += arglen;
    }

    command[len] = '\0';

    /* Fast path for non-assignment case */
    if (variable == NULL)
    {
        if (system(command))
        {
            if (!timer_exceeded)
                fprintf(stderr, "%s: could not launch shell command\n", argv[0]);
            return false;
        }
        return true;
    }

    /* Execute the command with pipe and read the standard output. */
    if ((fp = popen(command, "r")) == NULL)
    {
        fprintf(stderr, "%s: could not launch shell command\n", argv[0]);
        return false;
    }
    if (fgets(res, sizeof(res), fp) == NULL)
    {
        if (!timer_exceeded)
            fprintf(stderr, "%s: could not read result of shell command\n", argv[0]);
        (void) pclose(fp);
        return false;
    }
    if (pclose(fp) < 0)
    {
        fprintf(stderr, "%s: could not close shell command\n", argv[0]);
        return false;
    }

    /* Check whether the result is an integer and assign it to the variable */
    retval = (int) strtol(res, &endptr, 10);
    while (*endptr != '\0' && isspace((unsigned char) *endptr))
        endptr++;
    if (*res == '\0' || *endptr != '\0')
    {
        fprintf(stderr, "%s: shell command must return an integer (not \"%s\")\n",
                argv[0], res);
        return false;
    }
    if (!putVariableInt(st, "setshell", variable, retval))
        return false;

#ifdef DEBUG
    printf("shell parameter name: \"%s\", value: \"%s\"\n", argv[1], res);
#endif
    return true;
}

#define MAX_PREPARE_NAME        32
static void
preparedStatementName(char *buffer, int file, int state)
{
    sprintf(buffer, "P%d_%d", file, state);
}

static void
commandFailed(CState *st, const char *cmd, const char *message)
{
    fprintf(stderr,
            "client %d aborted in command %d (%s) of script %d; %s\n",
            st->id, st->command, cmd, st->use_file, message);
}

/* return a script number with a weighted choice. */
static int
chooseScript(TState *thread)
{
    int         i = 0;
    int64       w;

    if (num_scripts == 1)
        return 0;

    w = getrand(&thread->ts_choose_rs, 0, total_weight - 1);
    do
    {
        w -= sql_script[i++].weight;
    } while (w >= 0);

    return i - 1;
}

/* Send a SQL command, using the chosen querymode */
static bool
sendCommand(CState *st, Command *command)
{
    int         r;

    if (querymode == QUERY_SIMPLE)
    {
        char       *sql;

        sql = pg_strdup(command->argv[0]);
        sql = assignVariables(st, sql);

        if (debug)
            fprintf(stderr, "client %d sending %s\n", st->id, sql);
        r = PQsendQuery(st->con, sql);
        free(sql);
    }
    else if (querymode == QUERY_EXTENDED)
    {
        const char *sql = command->argv[0];
        const char *params[MAX_ARGS];

        getQueryParams(st, command, params);

        if (debug)
            fprintf(stderr, "client %d sending %s\n", st->id, sql);
        r = PQsendQueryParams(st->con, sql, command->argc - 1,
                              NULL, params, NULL, NULL, 0);
    }
    else if (querymode == QUERY_PREPARED)
    {
        char        name[MAX_PREPARE_NAME];
        const char *params[MAX_ARGS];

        if (!st->prepared[st->use_file])
        {
            int         j;
            Command   **commands = sql_script[st->use_file].commands;

            for (j = 0; commands[j] != NULL; j++)
            {
                PGresult   *res;
                char        name[MAX_PREPARE_NAME];

                if (commands[j]->type != SQL_COMMAND)
                    continue;
                preparedStatementName(name, st->use_file, j);
                res = PQprepare(st->con, name,
                                commands[j]->argv[0], commands[j]->argc - 1, NULL);
                if (PQresultStatus(res) != PGRES_COMMAND_OK)
                    fprintf(stderr, "%s", PQerrorMessage(st->con));
                PQclear(res);
            }
            st->prepared[st->use_file] = true;
        }

        getQueryParams(st, command, params);
        preparedStatementName(name, st->use_file, st->command);

        if (debug)
            fprintf(stderr, "client %d sending %s\n", st->id, name);
        r = PQsendQueryPrepared(st->con, name, command->argc - 1,
                                params, NULL, NULL, 0);
    }
    else                        /* unknown sql mode */
        r = 0;

    if (r == 0)
    {
        if (debug)
            fprintf(stderr, "client %d could not send %s\n",
                    st->id, command->argv[0]);
        st->ecnt++;
        return false;
    }
    else
        return true;
}

/*
 * Process query response from the backend.
 *
 * If varprefix is not NULL, it's the variable name prefix where to store
 * the results of the *last* command.
 *
 * Returns true if everything is A-OK, false if any error occurs.
 */
static bool
readCommandResponse(CState *st, char *varprefix)
{
    PGresult   *res;
    PGresult   *next_res;
    int         qrynum = 0;

    res = PQgetResult(st->con);

    while (res != NULL)
    {
        bool        is_last;

        /* peek at the next result to know whether the current is last */
        next_res = PQgetResult(st->con);
        is_last = (next_res == NULL);

        switch (PQresultStatus(res))
        {
            case PGRES_COMMAND_OK:  /* non-SELECT commands */
            case PGRES_EMPTY_QUERY: /* may be used for testing no-op overhead */
                if (is_last && varprefix != NULL)
                {
                    fprintf(stderr,
                            "client %d script %d command %d query %d: expected one row, got %d\n",
                            st->id, st->use_file, st->command, qrynum, 0);
                    goto error;
                }
                break;

            case PGRES_TUPLES_OK:
                if (is_last && varprefix != NULL)
                {
                    if (PQntuples(res) != 1)
                    {
                        fprintf(stderr,
                                "client %d script %d command %d query %d: expected one row, got %d\n",
                                st->id, st->use_file, st->command, qrynum, PQntuples(res));
                        goto error;
                    }

                    /* store results into variables */
                    for (int fld = 0; fld < PQnfields(res); fld++)
                    {
                        char       *varname = PQfname(res, fld);

                        /* allocate varname only if necessary, freed below */
                        if (*varprefix != '\0')
                            varname = psprintf("%s%s", varprefix, varname);

                        /* store result as a string */
                        if (!putVariable(st, "gset", varname,
                                         PQgetvalue(res, 0, fld)))
                        {
                            /* internal error */
                            fprintf(stderr,
                                    "client %d script %d command %d query %d: error storing into variable %s\n",
                                    st->id, st->use_file, st->command, qrynum,
                                    varname);
                            goto error;
                        }

                        if (*varprefix != '\0')
                            pg_free(varname);
                    }
                }
                /* otherwise the result is simply thrown away by PQclear below */
                break;

            default:
                /* anything else is unexpected */
                fprintf(stderr,
                        "client %d script %d aborted in command %d query %d: %s",
                        st->id, st->use_file, st->command, qrynum,
                        PQerrorMessage(st->con));
                goto error;
        }

        PQclear(res);
        qrynum++;
        res = next_res;
    }

    if (qrynum == 0)
    {
        fprintf(stderr, "client %d command %d: no results\n", st->id, st->command);
        st->ecnt++;
        return false;
    }

    return true;

error:
    st->ecnt++;
    PQclear(res);
    PQclear(next_res);
    do
    {
        res = PQgetResult(st->con);
        PQclear(res);
    } while (res);

    return false;
}

/*
 * Parse the argument to a \sleep command, and return the requested amount
 * of delay, in microseconds.  Returns true on success, false on error.
 */
static bool
evaluateSleep(CState *st, int argc, char **argv, int *usecs)
{
    char       *var;
    int         usec;

    if (*argv[1] == ':')
    {
        if ((var = getVariable(st, argv[1] + 1)) == NULL)
        {
            fprintf(stderr, "%s: undefined variable \"%s\"\n",
                    argv[0], argv[1]);
            return false;
        }
        usec = atoi(var);
    }
    else
        usec = atoi(argv[1]);

    if (argc > 2)
    {
        if (pg_strcasecmp(argv[2], "ms") == 0)
            usec *= 1000;
        else if (pg_strcasecmp(argv[2], "s") == 0)
            usec *= 1000000;
    }
    else
        usec *= 1000000;

    *usecs = usec;
    return true;
}

/*
 * Advance the state machine of a connection.
 */
static void
advanceConnectionState(TState *thread, CState *st, StatsData *agg)
{
    instr_time  now;

    /*
     * gettimeofday() isn't free, so we get the current timestamp lazily the
     * first time it's needed, and reuse the same value throughout this
     * function after that.  This also ensures that e.g. the calculated
     * latency reported in the log file and in the totals are the same. Zero
     * means "not set yet".  Reset "now" when we execute shell commands or
     * expressions, which might take a non-negligible amount of time, though.
     */
    INSTR_TIME_SET_ZERO(now);

    /*
     * Loop in the state machine, until we have to wait for a result from the
     * server or have to sleep for throttling or \sleep.
     *
     * Note: In the switch-statement below, 'break' will loop back here,
     * meaning "continue in the state machine".  Return is used to return to
     * the caller, giving the thread the opportunity to advance another
     * client.
     */
    for (;;)
    {
        Command    *command;

        switch (st->state)
        {
                /* Select transaction (script) to run.  */
            case CSTATE_CHOOSE_SCRIPT:
                st->use_file = chooseScript(thread);
                Assert(conditional_stack_empty(st->cstack));

                if (debug)
                    fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
                            sql_script[st->use_file].desc);

                /*
                 * If time is over, we're done; otherwise, get ready to start
                 * a new transaction, or to get throttled if that's requested.
                 */
                st->state = timer_exceeded ? CSTATE_FINISHED :
                    throttle_delay > 0 ? CSTATE_PREPARE_THROTTLE : CSTATE_START_TX;
                break;

                /* Start new transaction (script) */
            case CSTATE_START_TX:

                /* establish connection if needed, i.e. under --connect */
                if (st->con == NULL)
                {
                    instr_time  start;

                    INSTR_TIME_SET_CURRENT_LAZY(now);
                    start = now;
                    if ((st->con = doConnect()) == NULL)
                    {
                        fprintf(stderr, "client %d aborted while establishing connection\n",
                                st->id);
                        st->state = CSTATE_ABORTED;
                        break;
                    }
                    INSTR_TIME_SET_CURRENT(now);
                    INSTR_TIME_ACCUM_DIFF(thread->conn_time, now, start);

                    /* Reset session-local state */
                    memset(st->prepared, 0, sizeof(st->prepared));
                }

                /* record transaction start time */
                INSTR_TIME_SET_CURRENT_LAZY(now);
                st->txn_begin = now;

                /*
                 * When not throttling, this is also the transaction's
                 * scheduled start time.
                 */
                if (!throttle_delay)
                    st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now);

                /* Begin with the first command */
                st->state = CSTATE_START_COMMAND;
                st->command = 0;
                break;

                /*
                 * Handle throttling once per transaction by sleeping.
                 */
            case CSTATE_PREPARE_THROTTLE:

                /*
                 * Generate a delay such that the series of delays will
                 * approximate a Poisson distribution centered on the
                 * throttle_delay time.
                 *
                 * If transactions are too slow or a given wait is shorter
                 * than a transaction, the next transaction will start right
                 * away.
                 */
                Assert(throttle_delay > 0);

                thread->throttle_trigger +=
                    getPoissonRand(&thread->ts_throttle_rs, throttle_delay);
                st->txn_scheduled = thread->throttle_trigger;

                /*
                 * If --latency-limit is used, and this slot is already late
                 * so that the transaction will miss the latency limit even if
                 * it completed immediately, skip this time slot and schedule
                 * to continue running on the next slot that isn't late yet.
                 * But don't iterate beyond the -t limit, if one is given.
                 */
                if (latency_limit)
                {
                    int64       now_us;

                    INSTR_TIME_SET_CURRENT_LAZY(now);
                    now_us = INSTR_TIME_GET_MICROSEC(now);

                    while (thread->throttle_trigger < now_us - latency_limit &&
                           (nxacts <= 0 || st->cnt < nxacts))
                    {
                        processXactStats(thread, st, &now, true, agg);
                        /* next rendez-vous */
                        thread->throttle_trigger +=
                            getPoissonRand(&thread->ts_throttle_rs, throttle_delay);
                        st->txn_scheduled = thread->throttle_trigger;
                    }

                    /*
                     * stop client if -t was exceeded in the previous skip
                     * loop
                     */
                    if (nxacts > 0 && st->cnt >= nxacts)
                    {
                        st->state = CSTATE_FINISHED;
                        break;
                    }
                }

                /*
                 * stop client if next transaction is beyond pgbench end of
                 * execution; otherwise, throttle it.
                 */
                st->state = end_time > 0 && st->txn_scheduled > end_time ?
                    CSTATE_FINISHED : CSTATE_THROTTLE;
                break;

                /*
                 * Wait until it's time to start next transaction.
                 */
            case CSTATE_THROTTLE:
                INSTR_TIME_SET_CURRENT_LAZY(now);

                if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
                    return;     /* still sleeping, nothing to do here */

                /* done sleeping, but don't start transaction if we're done */
                st->state = timer_exceeded ? CSTATE_FINISHED : CSTATE_START_TX;
                break;

                /*
                 * Send a command to server (or execute a meta-command)
                 */
            case CSTATE_START_COMMAND:
                command = sql_script[st->use_file].commands[st->command];

                /* Transition to script end processing if done */
                if (command == NULL)
                {
                    st->state = CSTATE_END_TX;
                    break;
                }

                /* record begin time of next command, and initiate it */
                if (report_per_command)
                {
                    INSTR_TIME_SET_CURRENT_LAZY(now);
                    st->stmt_begin = now;
                }

                /* Execute the command */
                if (command->type == SQL_COMMAND)
                {
                    if (!sendCommand(st, command))
                    {
                        commandFailed(st, "SQL", "SQL command send failed");
                        st->state = CSTATE_ABORTED;
                    }
                    else
                        st->state = CSTATE_WAIT_RESULT;
                }
                else if (command->type == META_COMMAND)
                {
                    /*-----
                     * Possible state changes when executing meta commands:
                     * - on errors CSTATE_ABORTED
                     * - on sleep CSTATE_SLEEP
                     * - else CSTATE_END_COMMAND
                     */
                    st->state = executeMetaCommand(st, &now);
                }

                /*
                 * We're now waiting for an SQL command to complete, or
                 * finished processing a metacommand, or need to sleep, or
                 * something bad happened.
                 */
                Assert(st->state == CSTATE_WAIT_RESULT ||
                       st->state == CSTATE_END_COMMAND ||
                       st->state == CSTATE_SLEEP ||
                       st->state == CSTATE_ABORTED);
                break;

                /*
                 * non executed conditional branch
                 */
            case CSTATE_SKIP_COMMAND:
                Assert(!conditional_active(st->cstack));
                /* quickly skip commands until something to do... */
                while (true)
                {
                    Command    *command;

                    command = sql_script[st->use_file].commands[st->command];

                    /* cannot reach end of script in that state */
                    Assert(command != NULL);

                    /*
                     * if this is conditional related, update conditional
                     * state
                     */
                    if (command->type == META_COMMAND &&
                        (command->meta == META_IF ||
                         command->meta == META_ELIF ||
                         command->meta == META_ELSE ||
                         command->meta == META_ENDIF))
                    {
                        switch (conditional_stack_peek(st->cstack))
                        {
                            case IFSTATE_FALSE:
                                if (command->meta == META_IF ||
                                    command->meta == META_ELIF)
                                {
                                    /* we must evaluate the condition */
                                    st->state = CSTATE_START_COMMAND;
                                }
                                else if (command->meta == META_ELSE)
                                {
                                    /* we must execute next command */
                                    conditional_stack_poke(st->cstack,
                                                           IFSTATE_ELSE_TRUE);
                                    st->state = CSTATE_START_COMMAND;
                                    st->command++;
                                }
                                else if (command->meta == META_ENDIF)
                                {
                                    Assert(!conditional_stack_empty(st->cstack));
                                    conditional_stack_pop(st->cstack);
                                    if (conditional_active(st->cstack))
                                        st->state = CSTATE_START_COMMAND;

                                    /*
                                     * else state remains in
                                     * CSTATE_SKIP_COMMAND
                                     */
                                    st->command++;
                                }
                                break;

                            case IFSTATE_IGNORED:
                            case IFSTATE_ELSE_FALSE:
                                if (command->meta == META_IF)
                                    conditional_stack_push(st->cstack,
                                                           IFSTATE_IGNORED);
                                else if (command->meta == META_ENDIF)
                                {
                                    Assert(!conditional_stack_empty(st->cstack));
                                    conditional_stack_pop(st->cstack);
                                    if (conditional_active(st->cstack))
                                        st->state = CSTATE_START_COMMAND;
                                }
                                /* could detect "else" & "elif" after "else" */
                                st->command++;
                                break;

                            case IFSTATE_NONE:
                            case IFSTATE_TRUE:
                            case IFSTATE_ELSE_TRUE:
                            default:

                                /*
                                 * inconsistent if inactive, unreachable dead
                                 * code
                                 */
                                Assert(false);
                        }
                    }
                    else
                    {
                        /* skip and consider next */
                        st->command++;
                    }

                    if (st->state != CSTATE_SKIP_COMMAND)
                        /* out of quick skip command loop */
                        break;
                }
                break;

                /*
                 * Wait for the current SQL command to complete
                 */
            case CSTATE_WAIT_RESULT:
                if (debug)
                    fprintf(stderr, "client %d receiving\n", st->id);
                if (!PQconsumeInput(st->con))
                {
                    /* there's something wrong */
                    commandFailed(st, "SQL", "perhaps the backend died while processing");
                    st->state = CSTATE_ABORTED;
                    break;
                }
                if (PQisBusy(st->con))
                    return;     /* don't have the whole result yet */

                /* store or discard the query results */
                if (readCommandResponse(st, sql_script[st->use_file].commands[st->command]->varprefix))
                    st->state = CSTATE_END_COMMAND;
                else
                    st->state = CSTATE_ABORTED;
                break;

                /*
                 * Wait until sleep is done. This state is entered after a
                 * \sleep metacommand. The behavior is similar to
                 * CSTATE_THROTTLE, but proceeds to CSTATE_START_COMMAND
                 * instead of CSTATE_START_TX.
                 */
            case CSTATE_SLEEP:
                INSTR_TIME_SET_CURRENT_LAZY(now);
                if (INSTR_TIME_GET_MICROSEC(now) < st->sleep_until)
                    return;     /* still sleeping, nothing to do here */
                /* Else done sleeping. */
                st->state = CSTATE_END_COMMAND;
                break;

                /*
                 * End of command: record stats and proceed to next command.
                 */
            case CSTATE_END_COMMAND:

                /*
                 * command completed: accumulate per-command execution times
                 * in thread-local data structure, if per-command latencies
                 * are requested.
                 */
                if (report_per_command)
                {
                    Command    *command;

                    INSTR_TIME_SET_CURRENT_LAZY(now);

                    command = sql_script[st->use_file].commands[st->command];
                    /* XXX could use a mutex here, but we choose not to */
                    addToSimpleStats(&command->stats,
                                     INSTR_TIME_GET_DOUBLE(now) -
                                     INSTR_TIME_GET_DOUBLE(st->stmt_begin));
                }

                /* Go ahead with next command, to be executed or skipped */
                st->command++;
                st->state = conditional_active(st->cstack) ?
                    CSTATE_START_COMMAND : CSTATE_SKIP_COMMAND;
                break;

                /*
                 * End of transaction (end of script, really).
                 */
            case CSTATE_END_TX:

                /* transaction finished: calculate latency and do log */
                processXactStats(thread, st, &now, false, agg);

                /*
                 * missing \endif... cannot happen if CheckConditional was
                 * okay
                 */
                Assert(conditional_stack_empty(st->cstack));

                if (is_connect)
                {
                    finishCon(st);
                    INSTR_TIME_SET_ZERO(now);
                }

                if ((st->cnt >= nxacts && duration <= 0) || timer_exceeded)
                {
                    /* script completed */
                    st->state = CSTATE_FINISHED;
                    break;
                }

                /* next transaction (script) */
                st->state = CSTATE_CHOOSE_SCRIPT;

                /*
                 * Ensure that we always return on this point, so as to avoid
                 * an infinite loop if the script only contains meta commands.
                 */
                return;

                /*
                 * Final states.  Close the connection if it's still open.
                 */
            case CSTATE_ABORTED:
            case CSTATE_FINISHED:
                finishCon(st);
                return;
        }
    }
}

/*
 * Subroutine for advanceConnectionState -- initiate or execute the current
 * meta command, and return the next state to set.
 *
 * *now is updated to the current time, unless the command is expected to
 * take no time to execute.
 */
static ConnectionStateEnum
executeMetaCommand(CState *st, instr_time *now)
{
    Command    *command = sql_script[st->use_file].commands[st->command];
    int         argc;
    char      **argv;

    Assert(command != NULL && command->type == META_COMMAND);

    argc = command->argc;
    argv = command->argv;

    if (debug)
    {
        fprintf(stderr, "client %d executing \\%s", st->id, argv[0]);
        for (int i = 1; i < argc; i++)
            fprintf(stderr, " %s", argv[i]);
        fprintf(stderr, "\n");
    }

    if (command->meta == META_SLEEP)
    {
        int         usec;

        /*
         * A \sleep doesn't execute anything, we just get the delay from the
         * argument, and enter the CSTATE_SLEEP state.  (The per-command
         * latency will be recorded in CSTATE_SLEEP state, not here, after the
         * delay has elapsed.)
         */
        if (!evaluateSleep(st, argc, argv, &usec))
        {
            commandFailed(st, "sleep", "execution of meta-command failed");
            return CSTATE_ABORTED;
        }

        INSTR_TIME_SET_CURRENT_LAZY(*now);
        st->sleep_until = INSTR_TIME_GET_MICROSEC(*now) + usec;
        return CSTATE_SLEEP;
    }
    else if (command->meta == META_SET)
    {
        PgBenchExpr *expr = command->expr;
        PgBenchValue result;

        if (!evaluateExpr(st, expr, &result))
        {
            commandFailed(st, argv[0], "evaluation of meta-command failed");
            return CSTATE_ABORTED;
        }

        if (!putVariableValue(st, argv[0], argv[1], &result))
        {
            commandFailed(st, "set", "assignment of meta-command failed");
            return CSTATE_ABORTED;
        }
    }
    else if (command->meta == META_IF)
    {
        /* backslash commands with an expression to evaluate */
        PgBenchExpr *expr = command->expr;
        PgBenchValue result;
        bool        cond;

        if (!evaluateExpr(st, expr, &result))
        {
            commandFailed(st, argv[0], "evaluation of meta-command failed");
            return CSTATE_ABORTED;
        }

        cond = valueTruth(&result);
        conditional_stack_push(st->cstack, cond ? IFSTATE_TRUE : IFSTATE_FALSE);
    }
    else if (command->meta == META_ELIF)
    {
        /* backslash commands with an expression to evaluate */
        PgBenchExpr *expr = command->expr;
        PgBenchValue result;
        bool        cond;

        if (conditional_stack_peek(st->cstack) == IFSTATE_TRUE)
        {
            /* elif after executed block, skip eval and wait for endif. */
            conditional_stack_poke(st->cstack, IFSTATE_IGNORED);
            return CSTATE_END_COMMAND;
        }

        if (!evaluateExpr(st, expr, &result))
        {
            commandFailed(st, argv[0], "evaluation of meta-command failed");
            return CSTATE_ABORTED;
        }

        cond = valueTruth(&result);
        Assert(conditional_stack_peek(st->cstack) == IFSTATE_FALSE);
        conditional_stack_poke(st->cstack, cond ? IFSTATE_TRUE : IFSTATE_FALSE);
    }
    else if (command->meta == META_ELSE)
    {
        switch (conditional_stack_peek(st->cstack))
        {
            case IFSTATE_TRUE:
                conditional_stack_poke(st->cstack, IFSTATE_ELSE_FALSE);
                break;
            case IFSTATE_FALSE: /* inconsistent if active */
            case IFSTATE_IGNORED:   /* inconsistent if active */
            case IFSTATE_NONE:  /* else without if */
            case IFSTATE_ELSE_TRUE: /* else after else */
            case IFSTATE_ELSE_FALSE:    /* else after else */
            default:
                /* dead code if conditional check is ok */
                Assert(false);
        }
    }
    else if (command->meta == META_ENDIF)
    {
        Assert(!conditional_stack_empty(st->cstack));
        conditional_stack_pop(st->cstack);
    }
    else if (command->meta == META_SETSHELL)
    {
        if (!runShellCommand(st, argv[1], argv + 2, argc - 2))
        {
            commandFailed(st, "setshell", "execution of meta-command failed");
            return CSTATE_ABORTED;
        }
    }
    else if (command->meta == META_SHELL)
    {
        if (!runShellCommand(st, NULL, argv + 1, argc - 1))
        {
            commandFailed(st, "shell", "execution of meta-command failed");
            return CSTATE_ABORTED;
        }
    }

    /*
     * executing the expression or shell command might have taken a
     * non-negligible amount of time, so reset 'now'
     */
    INSTR_TIME_SET_ZERO(*now);

    return CSTATE_END_COMMAND;
}

/*
 * Print log entry after completing one transaction.
 *
 * We print Unix-epoch timestamps in the log, so that entries can be
 * correlated against other logs.  On some platforms this could be obtained
 * from the instr_time reading the caller has, but rather than get entangled
 * with that, we just eat the cost of an extra syscall in all cases.
 */
static void
doLog(TState *thread, CState *st,
      StatsData *agg, bool skipped, double latency, double lag)
{
    FILE       *logfile = thread->logfile;

    Assert(use_log);

    /*
     * Skip the log entry if sampling is enabled and this row doesn't belong
     * to the random sample.
     */
    if (sample_rate != 0.0 &&
        pg_erand48(thread->ts_sample_rs.xseed) > sample_rate)
        return;

    /* should we aggregate the results or not? */
    if (agg_interval > 0)
    {
        /*
         * Loop until we reach the interval of the current moment, and print
         * any empty intervals in between (this may happen with very low tps,
         * e.g. --rate=0.1).
         */
        time_t      now = time(NULL);

        while (agg->start_time + agg_interval <= now)
        {
            /* print aggregated report to logfile */
            fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
                    (long) agg->start_time,
                    agg->cnt,
                    agg->latency.sum,
                    agg->latency.sum2,
                    agg->latency.min,
                    agg->latency.max);
            if (throttle_delay)
            {
                fprintf(logfile, " %.0f %.0f %.0f %.0f",
                        agg->lag.sum,
                        agg->lag.sum2,
                        agg->lag.min,
                        agg->lag.max);
                if (latency_limit)
                    fprintf(logfile, " " INT64_FORMAT, agg->skipped);
            }
            fputc('\n', logfile);

            /* reset data and move to next interval */
            initStats(agg, agg->start_time + agg_interval);
        }

        /* accumulate the current transaction */
        accumStats(agg, skipped, latency, lag);
    }
    else
    {
        /* no, print raw transactions */
        struct timeval tv;

        gettimeofday(&tv, NULL);
        if (skipped)
            fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
                    st->id, st->cnt, st->use_file,
                    (long) tv.tv_sec, (long) tv.tv_usec);
        else
            fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
                    st->id, st->cnt, latency, st->use_file,
                    (long) tv.tv_sec, (long) tv.tv_usec);
        if (throttle_delay)
            fprintf(logfile, " %.0f", lag);
        fputc('\n', logfile);
    }
}

/*
 * Accumulate and report statistics at end of a transaction.
 *
 * (This is also called when a transaction is late and thus skipped.
 * Note that even skipped transactions are counted in the "cnt" fields.)
 */
static void
processXactStats(TState *thread, CState *st, instr_time *now,
                 bool skipped, StatsData *agg)
{
    double      latency = 0.0,
                lag = 0.0;
    bool        thread_details = progress || throttle_delay || latency_limit,
                detailed = thread_details || use_log || per_script_stats;

    if (detailed && !skipped)
    {
        INSTR_TIME_SET_CURRENT_LAZY(*now);

        /* compute latency & lag */
        latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
        lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
    }

    if (thread_details)
    {
        /* keep detailed thread stats */
        accumStats(&thread->stats, skipped, latency, lag);

        /* count transactions over the latency limit, if needed */
        if (latency_limit && latency > latency_limit)
            thread->latency_late++;
    }
    else
    {
        /* no detailed stats, just count */
        thread->stats.cnt++;
    }

    /* client stat is just counting */
    st->cnt++;

    if (use_log)
        doLog(thread, st, agg, skipped, latency, lag);

    /* XXX could use a mutex here, but we choose not to */
    if (per_script_stats)
        accumStats(&sql_script[st->use_file].stats, skipped, latency, lag);
}


/* discard connections */
static void
disconnect_all(CState *state, int length)
{
    int         i;

    for (i = 0; i < length; i++)
        finishCon(&state[i]);
}

/*
 * Remove old pgbench tables, if any exist
 */
static void
initDropTables(PGconn *con)
{
    fprintf(stderr, "dropping old tables...\n");

    /*
     * We drop all the tables in one command, so that whether there are
     * foreign key dependencies or not doesn't matter.
     */
    executeStatement(con, "drop table if exists "
                     "pgbench_accounts, "
                     "pgbench_branches, "
                     "pgbench_history, "
                     "pgbench_tellers");
}

/*
 * Create "pgbench_accounts" partitions if needed.
 *
 * This is the larger table of pgbench default tpc-b like schema
 * with a known size, so we choose to partition it.
 */
static void
createPartitions(PGconn *con)
{
    char        ff[64];

    ff[0] = '\0';

    /*
     * Per ddlinfo in initCreateTables, fillfactor is needed on table
     * pgbench_accounts.
     */
    append_fillfactor(ff, sizeof(ff));

    /* we must have to create some partitions */
    Assert(partitions > 0);

    fprintf(stderr, "creating %d partitions...\n", partitions);

    for (int p = 1; p <= partitions; p++)
    {
        char        query[256];

        if (partition_method == PART_RANGE)
        {
            int64       part_size = (naccounts * (int64) scale + partitions - 1) / partitions;
            char        minvalue[32],
                        maxvalue[32];

            /*
             * For RANGE, we use open-ended partitions at the beginning and
             * end to allow any valid value for the primary key.  Although the
             * actual minimum and maximum values can be derived from the
             * scale, it is more generic and the performance is better.
             */
            if (p == 1)
                sprintf(minvalue, "minvalue");
            else
                sprintf(minvalue, INT64_FORMAT, (p - 1) * part_size + 1);

            if (p < partitions)
                sprintf(maxvalue, INT64_FORMAT, p * part_size + 1);
            else
                sprintf(maxvalue, "maxvalue");

            snprintf(query, sizeof(query),
                     "create%s table pgbench_accounts_%d\n"
                     "  partition of pgbench_accounts\n"
                     "  for values from (%s) to (%s)%s\n",
                     unlogged_tables ? " unlogged" : "", p,
                     minvalue, maxvalue, ff);
        }
        else if (partition_method == PART_HASH)
            snprintf(query, sizeof(query),
                     "create%s table pgbench_accounts_%d\n"
                     "  partition of pgbench_accounts\n"
                     "  for values with (modulus %d, remainder %d)%s\n",
                     unlogged_tables ? " unlogged" : "", p,
                     partitions, p - 1, ff);
        else                    /* cannot get there */
            Assert(0);

        executeStatement(con, query);
    }
}

/*
 * Create pgbench's standard tables
 */
static void
initCreateTables(PGconn *con)
{
    /*
     * Note: TPC-B requires at least 100 bytes per row, and the "filler"
     * fields in these table declarations were intended to comply with that.
     * The pgbench_accounts table complies with that because the "filler"
     * column is set to blank-padded empty string. But for all other tables
     * the columns default to NULL and so don't actually take any space.  We
     * could fix that by giving them non-null default values.  However, that
     * would completely break comparability of pgbench results with prior
     * versions. Since pgbench has never pretended to be fully TPC-B compliant
     * anyway, we stick with the historical behavior.
     */
    struct ddlinfo
    {
        const char *table;      /* table name */
        const char *smcols;     /* column decls if accountIDs are 32 bits */
        const char *bigcols;    /* column decls if accountIDs are 64 bits */
        int         declare_fillfactor;
    };
    static const struct ddlinfo DDLs[] = {
        {
            "pgbench_history",
            "tid int,bid int,aid    int,delta int,mtime timestamp,filler char(22)",
            "tid int,bid int,aid bigint,delta int,mtime timestamp,filler char(22)",
            0
        },
        {
            "pgbench_tellers",
            "tid int not null,bid int,tbalance int,filler char(84)",
            "tid int not null,bid int,tbalance int,filler char(84)",
            1
        },
        {
            "pgbench_accounts",
            "aid    int not null,bid int,abalance int,filler char(84)",
            "aid bigint not null,bid int,abalance int,filler char(84)",
            1
        },
        {
            "pgbench_branches",
            "bid int not null,bbalance int,filler char(88)",
            "bid int not null,bbalance int,filler char(88)",
            1
        }
    };
    int         i;

    fprintf(stderr, "creating tables...\n");

    for (i = 0; i < lengthof(DDLs); i++)
    {
        char        opts[256];
        char        buffer[256];
        const struct ddlinfo *ddl = &DDLs[i];
        const char *cols;

        /* Construct new create table statement. */
        opts[0] = '\0';

        /* Partition pgbench_accounts table */
        if (partition_method != PART_NONE && strcmp(ddl->table, "pgbench_accounts") == 0)
            snprintf(opts + strlen(opts), sizeof(opts) - strlen(opts),
                     " partition by %s (aid)", PARTITION_METHOD[partition_method]);
        else if (ddl->declare_fillfactor)
            /* fillfactor is only expected on actual tables */
            append_fillfactor(opts, sizeof(opts));

        if (tablespace != NULL)
        {
            char       *escape_tablespace;

            escape_tablespace = PQescapeIdentifier(con, tablespace,
                                                   strlen(tablespace));
            snprintf(opts + strlen(opts), sizeof(opts) - strlen(opts),
                     " tablespace %s", escape_tablespace);
            PQfreemem(escape_tablespace);
        }

        cols = (scale >= SCALE_32BIT_THRESHOLD) ? ddl->bigcols : ddl->smcols;

        snprintf(buffer, sizeof(buffer), "create%s table %s(%s)%s",
                 unlogged_tables ? " unlogged" : "",
                 ddl->table, cols, opts);

        executeStatement(con, buffer);
    }

    if (partition_method != PART_NONE)
        createPartitions(con);
}

/*
 * add fillfactor percent option.
 *
 * XXX - As default is 100, it could be removed in this case.
 */
static void
append_fillfactor(char *opts, int len)
{
    snprintf(opts + strlen(opts), len - strlen(opts),
             " with (fillfactor=%d)", fillfactor);
}

/*
 * Truncate away any old data, in one command in case there are foreign keys
 */
static void
initTruncateTables(PGconn *con)
{
    executeStatement(con, "truncate table "
                     "pgbench_accounts, "
                     "pgbench_branches, "
                     "pgbench_history, "
                     "pgbench_tellers");
}

/*
 * Fill the standard tables with some data generated and sent from the client
 */
static void
initGenerateDataClientSide(PGconn *con)
{
    char        sql[256];
    PGresult   *res;
    int         i;
    int64       k;

    /* used to track elapsed time and estimate of the remaining time */
    instr_time  start,
                diff;
    double      elapsed_sec,
                remaining_sec;
    int         log_interval = 1;

    fprintf(stderr, "generating data (client-side)...\n");

    /*
     * we do all of this in one transaction to enable the backend's
     * data-loading optimizations
     */
    executeStatement(con, "begin");

    /* truncate away any old data */
    initTruncateTables(con);

    /*
     * fill branches, tellers, accounts in that order in case foreign keys
     * already exist
     */
    for (i = 0; i < nbranches * scale; i++)
    {
        /* "filler" column defaults to NULL */
        snprintf(sql, sizeof(sql),
                 "insert into pgbench_branches(bid,bbalance) values(%d,0)",
                 i + 1);
        executeStatement(con, sql);
    }

    for (i = 0; i < ntellers * scale; i++)
    {
        /* "filler" column defaults to NULL */
        snprintf(sql, sizeof(sql),
                 "insert into pgbench_tellers(tid,bid,tbalance) values (%d,%d,0)",
                 i + 1, i / ntellers + 1);
        executeStatement(con, sql);
    }

    /*
     * accounts is big enough to be worth using COPY and tracking runtime
     */
    res = PQexec(con, "copy pgbench_accounts from stdin");
    if (PQresultStatus(res) != PGRES_COPY_IN)
    {
        fprintf(stderr, "%s", PQerrorMessage(con));
        exit(1);
    }
    PQclear(res);

    INSTR_TIME_SET_CURRENT(start);

    for (k = 0; k < (int64) naccounts * scale; k++)
    {
        int64       j = k + 1;

        /* "filler" column defaults to blank padded empty string */
        snprintf(sql, sizeof(sql),
                 INT64_FORMAT "\t" INT64_FORMAT "\t%d\t\n",
                 j, k / naccounts + 1, 0);
        if (PQputline(con, sql))
        {
            fprintf(stderr, "PQputline failed\n");
            exit(1);
        }

        /*
         * If we want to stick with the original logging, print a message each
         * 100k inserted rows.
         */
        if ((!use_quiet) && (j % 100000 == 0))
        {
            INSTR_TIME_SET_CURRENT(diff);
            INSTR_TIME_SUBTRACT(diff, start);

            elapsed_sec = INSTR_TIME_GET_DOUBLE(diff);
            remaining_sec = ((double) scale * naccounts - j) * elapsed_sec / j;

            fprintf(stderr, INT64_FORMAT " of " INT64_FORMAT " tuples (%d%%) done (elapsed %.2f s, remaining %.2f s)\n",
                    j, (int64) naccounts * scale,
                    (int) (((int64) j * 100) / (naccounts * (int64) scale)),
                    elapsed_sec, remaining_sec);
        }
        /* let's not call the timing for each row, but only each 100 rows */
        else if (use_quiet && (j % 100 == 0))
        {
            INSTR_TIME_SET_CURRENT(diff);
            INSTR_TIME_SUBTRACT(diff, start);

            elapsed_sec = INSTR_TIME_GET_DOUBLE(diff);
            remaining_sec = ((double) scale * naccounts - j) * elapsed_sec / j;

            /* have we reached the next interval (or end)? */
            if ((j == scale * naccounts) || (elapsed_sec >= log_interval * LOG_STEP_SECONDS))
            {
                fprintf(stderr, INT64_FORMAT " of " INT64_FORMAT " tuples (%d%%) done (elapsed %.2f s, remaining %.2f s)\n",
                        j, (int64) naccounts * scale,
                        (int) (((int64) j * 100) / (naccounts * (int64) scale)), elapsed_sec, remaining_sec);

                /* skip to the next interval */
                log_interval = (int) ceil(elapsed_sec / LOG_STEP_SECONDS);
            }
        }

    }
    if (PQputline(con, "\\.\n"))
    {
        fprintf(stderr, "very last PQputline failed\n");
        exit(1);
    }
    if (PQendcopy(con))
    {
        fprintf(stderr, "PQendcopy failed\n");
        exit(1);
    }

    executeStatement(con, "commit");
}

/*
 * Fill the standard tables with some data generated on the server
 *
 * As already the case with the client-side data generation, the filler
 * column defaults to NULL in pgbench_branches and pgbench_tellers,
 * and is a blank-padded string in pgbench_accounts.
 */
static void
initGenerateDataServerSide(PGconn *con)
{
    char        sql[256];

    fprintf(stderr, "generating data (server-side)...\n");

    /*
     * we do all of this in one transaction to enable the backend's
     * data-loading optimizations
     */
    executeStatement(con, "begin");

    /* truncate away any old data */
    initTruncateTables(con);

    snprintf(sql, sizeof(sql),
             "insert into pgbench_branches(bid,bbalance) "
             "select bid, 0 "
             "from generate_series(1, %d) as bid", nbranches * scale);
    executeStatement(con, sql);

    snprintf(sql, sizeof(sql),
             "insert into pgbench_tellers(tid,bid,tbalance) "
             "select tid, (tid - 1) / %d + 1, 0 "
             "from generate_series(1, %d) as tid", ntellers, ntellers * scale);
    executeStatement(con, sql);

    snprintf(sql, sizeof(sql),
             "insert into pgbench_accounts(aid,bid,abalance,filler) "
             "select aid, (aid - 1) / %d + 1, 0, '' "
             "from generate_series(1, "INT64_FORMAT") as aid",
             naccounts, (int64) naccounts * scale);
    executeStatement(con, sql);

    executeStatement(con, "commit");
}

/*
 * Invoke vacuum on the standard tables
 */
static void
initVacuum(PGconn *con)
{
    fprintf(stderr, "vacuuming...\n");
    executeStatement(con, "vacuum analyze pgbench_branches");
    executeStatement(con, "vacuum analyze pgbench_tellers");
    executeStatement(con, "vacuum analyze pgbench_accounts");
    executeStatement(con, "vacuum analyze pgbench_history");
}

/*
 * Create primary keys on the standard tables
 */
static void
initCreatePKeys(PGconn *con)
{
    static const char *const DDLINDEXes[] = {
        "alter table pgbench_branches add primary key (bid)",
        "alter table pgbench_tellers add primary key (tid)",
        "alter table pgbench_accounts add primary key (aid)"
    };
    int         i;

    fprintf(stderr, "creating primary keys...\n");
    for (i = 0; i < lengthof(DDLINDEXes); i++)
    {
        char        buffer[256];

        strlcpy(buffer, DDLINDEXes[i], sizeof(buffer));

        if (index_tablespace != NULL)
        {
            char       *escape_tablespace;

            escape_tablespace = PQescapeIdentifier(con, index_tablespace,
                                                   strlen(index_tablespace));
            snprintf(buffer + strlen(buffer), sizeof(buffer) - strlen(buffer),
                     " using index tablespace %s", escape_tablespace);
            PQfreemem(escape_tablespace);
        }

        executeStatement(con, buffer);
    }
}

/*
 * Create foreign key constraints between the standard tables
 */
static void
initCreateFKeys(PGconn *con)
{
    static const char *const DDLKEYs[] = {
        "alter table pgbench_tellers add constraint pgbench_tellers_bid_fkey foreign key (bid) references pgbench_branches",
        "alter table pgbench_accounts add constraint pgbench_accounts_bid_fkey foreign key (bid) references pgbench_branches",
        "alter table pgbench_history add constraint pgbench_history_bid_fkey foreign key (bid) references pgbench_branches",
        "alter table pgbench_history add constraint pgbench_history_tid_fkey foreign key (tid) references pgbench_tellers",
        "alter table pgbench_history add constraint pgbench_history_aid_fkey foreign key (aid) references pgbench_accounts"
    };
    int         i;

    fprintf(stderr, "creating foreign keys...\n");
    for (i = 0; i < lengthof(DDLKEYs); i++)
    {
        executeStatement(con, DDLKEYs[i]);
    }
}

/*
 * Validate an initialization-steps string
 *
 * (We could just leave it to runInitSteps() to fail if there are wrong
 * characters, but since initialization can take awhile, it seems friendlier
 * to check during option parsing.)
 */
static void
checkInitSteps(const char *initialize_steps)
{
    if (initialize_steps[0] == '\0')
    {
        fprintf(stderr, "no initialization steps specified\n");
        exit(1);
    }

    for (const char *step = initialize_steps; *step != '\0'; step++)
    {
        if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
        {
            fprintf(stderr,
                    "unrecognized initialization step \"%c\"\n",
                    *step);
            fprintf(stderr,
                    "Allowed step characters are: \"" ALL_INIT_STEPS "\".\n");
            exit(1);
        }
    }
}

/*
 * Invoke each initialization step in the given string
 */
static void
runInitSteps(const char *initialize_steps)
{
    PQExpBufferData stats;
    PGconn     *con;
    const char *step;
    double      run_time = 0.0;
    bool        first = true;

    initPQExpBuffer(&stats);

    if ((con = doConnect()) == NULL)
        exit(1);

    for (step = initialize_steps; *step != '\0'; step++)
    {
        instr_time  start;
        char       *op = NULL;

        INSTR_TIME_SET_CURRENT(start);

        switch (*step)
        {
            case 'd':
                op = "drop tables";
                initDropTables(con);
                break;
            case 't':
                op = "create tables";
                initCreateTables(con);
                break;
            case 'g':
                op = "client-side generate";
                initGenerateDataClientSide(con);
                break;
            case 'G':
                op = "server-side generate";
                initGenerateDataServerSide(con);
                break;
            case 'v':
                op = "vacuum";
                initVacuum(con);
                break;
            case 'p':
                op = "primary keys";
                initCreatePKeys(con);
                break;
            case 'f':
                op = "foreign keys";
                initCreateFKeys(con);
                break;
            case ' ':
                break;          /* ignore */
            default:
                fprintf(stderr, "unrecognized initialization step \"%c\"\n",
                        *step);
                PQfinish(con);
                exit(1);
        }

        if (op != NULL)
        {
            instr_time  diff;
            double      elapsed_sec;

            INSTR_TIME_SET_CURRENT(diff);
            INSTR_TIME_SUBTRACT(diff, start);
            elapsed_sec = INSTR_TIME_GET_DOUBLE(diff);

            if (!first)
                appendPQExpBufferStr(&stats, ", ");
            else
                first = false;

            appendPQExpBuffer(&stats, "%s %.2f s", op, elapsed_sec);

            run_time += elapsed_sec;
        }
    }

    fprintf(stderr, "done in %.2f s (%s).\n", run_time, stats.data);
    PQfinish(con);
    termPQExpBuffer(&stats);
}

/*
 * Extract pgbench table informations into global variables scale,
 * partition_method and partitions.
 */
static void
GetTableInfo(PGconn *con, bool scale_given)
{
    PGresult   *res;

    /*
     * get the scaling factor that should be same as count(*) from
     * pgbench_branches if this is not a custom query
     */
    res = PQexec(con, "select count(*) from pgbench_branches");
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        char       *sqlState = PQresultErrorField(res, PG_DIAG_SQLSTATE);

        fprintf(stderr, "%s", PQerrorMessage(con));
        if (sqlState && strcmp(sqlState, ERRCODE_UNDEFINED_TABLE) == 0)
        {
            fprintf(stderr, "Perhaps you need to do initialization (\"pgbench -i\") in database \"%s\"\n", PQdb(con));
        }

        exit(1);
    }
    scale = atoi(PQgetvalue(res, 0, 0));
    if (scale < 0)
    {
        fprintf(stderr, "invalid count(*) from pgbench_branches: \"%s\"\n",
                PQgetvalue(res, 0, 0));
        exit(1);
    }
    PQclear(res);

    /* warn if we override user-given -s switch */
    if (scale_given)
        fprintf(stderr,
                "scale option ignored, using count from pgbench_branches table (%d)\n",
                scale);

    /*
     * Get the partition information for the first "pgbench_accounts" table
     * found in search_path.
     *
     * The result is empty if no "pgbench_accounts" is found.
     *
     * Otherwise, it always returns one row even if the table is not
     * partitioned (in which case the partition strategy is NULL).
     *
     * The number of partitions can be 0 even for partitioned tables, if no
     * partition is attached.
     *
     * We assume no partitioning on any failure, so as to avoid failing on an
     * old version without "pg_partitioned_table".
     */
    res = PQexec(con,
                 "select o.n, p.partstrat, pg_catalog.count(i.inhparent) "
                 "from pg_catalog.pg_class as c "
                 "join pg_catalog.pg_namespace as n on (n.oid = c.relnamespace) "
                 "cross join lateral (select pg_catalog.array_position(pg_catalog.current_schemas(true), n.nspname)) as o(n) "
                 "left join pg_catalog.pg_partitioned_table as p on (p.partrelid = c.oid) "
                 "left join pg_catalog.pg_inherits as i on (c.oid = i.inhparent) "
                 "where c.relname = 'pgbench_accounts' and o.n is not null "
                 "group by 1, 2 "
                 "order by 1 asc "
                 "limit 1");

    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        /* probably an older version, coldly assume no partitioning */
        partition_method = PART_NONE;
        partitions = 0;
    }
    else if (PQntuples(res) == 0)
    {
        /*
         * This case is unlikely as pgbench already found "pgbench_branches"
         * above to compute the scale.
         */
        fprintf(stderr,
                "no pgbench_accounts table found in search_path\n"
                "Perhaps you need to do initialization (\"pgbench -i\") in database \"%s\".\n", PQdb(con));
        exit(1);
    }
    else                        /* PQntupes(res) == 1 */
    {
        /* normal case, extract partition information */
        if (PQgetisnull(res, 0, 1))
            partition_method = PART_NONE;
        else
        {
            char       *ps = PQgetvalue(res, 0, 1);

            /* column must be there */
            Assert(ps != NULL);

            if (strcmp(ps, "r") == 0)
                partition_method = PART_RANGE;
            else if (strcmp(ps, "h") == 0)
                partition_method = PART_HASH;
            else
            {
                /* possibly a newer version with new partition method */
                fprintf(stderr, "unexpected partition method: \"%s\"\n", ps);
                exit(1);
            }
        }

        partitions = atoi(PQgetvalue(res, 0, 2));
    }

    PQclear(res);
}

/*
 * Replace :param with $n throughout the command's SQL text, which
 * is a modifiable string in cmd->lines.
 */
static bool
parseQuery(Command *cmd)
{
    char       *sql,
               *p;

    cmd->argc = 1;

    p = sql = pg_strdup(cmd->lines.data);
    while ((p = strchr(p, ':')) != NULL)
    {
        char        var[13];
        char       *name;
        int         eaten;

        name = parseVariable(p, &eaten);
        if (name == NULL)
        {
            while (*p == ':')
            {
                p++;
            }
            continue;
        }

        /*
         * cmd->argv[0] is the SQL statement itself, so the max number of
         * arguments is one less than MAX_ARGS
         */
        if (cmd->argc >= MAX_ARGS)
        {
            fprintf(stderr, "statement has too many arguments (maximum is %d): %s\n",
                    MAX_ARGS - 1, cmd->lines.data);
            pg_free(name);
            return false;
        }

        sprintf(var, "$%d", cmd->argc);
        p = replaceVariable(&sql, p, eaten, var);

        cmd->argv[cmd->argc] = name;
        cmd->argc++;
    }

    Assert(cmd->argv[0] == NULL);
    cmd->argv[0] = sql;
    return true;
}

/*
 * syntax error while parsing a script (in practice, while parsing a
 * backslash command, because we don't detect syntax errors in SQL)
 *
 * source: source of script (filename or builtin-script ID)
 * lineno: line number within script (count from 1)
 * line: whole line of backslash command, if available
 * command: backslash command name, if available
 * msg: the actual error message
 * more: optional extra message
 * column: zero-based column number, or -1 if unknown
 */
void
syntax_error(const char *source, int lineno,
             const char *line, const char *command,
             const char *msg, const char *more, int column)
{
    fprintf(stderr, "%s:%d: %s", source, lineno, msg);
    if (more != NULL)
        fprintf(stderr, " (%s)", more);
    if (column >= 0 && line == NULL)
        fprintf(stderr, " at column %d", column + 1);
    if (command != NULL)
        fprintf(stderr, " in command \"%s\"", command);
    fprintf(stderr, "\n");
    if (line != NULL)
    {
        fprintf(stderr, "%s\n", line);
        if (column >= 0)
        {
            int         i;

            for (i = 0; i < column; i++)
                fprintf(stderr, " ");
            fprintf(stderr, "^ error found here\n");
        }
    }
    exit(1);
}

/*
 * Return a pointer to the start of the SQL command, after skipping over
 * whitespace and "--" comments.
 * If the end of the string is reached, return NULL.
 */
static char *
skip_sql_comments(char *sql_command)
{
    char       *p = sql_command;

    /* Skip any leading whitespace, as well as "--" style comments */
    for (;;)
    {
        if (isspace((unsigned char) *p))
            p++;
        else if (strncmp(p, "--", 2) == 0)
        {
            p = strchr(p, '\n');
            if (p == NULL)
                return NULL;
            p++;
        }
        else
            break;
    }

    /* NULL if there's nothing but whitespace and comments */
    if (*p == '\0')
        return NULL;

    return p;
}

/*
 * Parse a SQL command; return a Command struct, or NULL if it's a comment
 *
 * On entry, psqlscan.l has collected the command into "buf", so we don't
 * really need to do much here except check for comments and set up a Command
 * struct.
 */
static Command *
create_sql_command(PQExpBuffer buf, const char *source)
{
    Command    *my_command;
    char       *p = skip_sql_comments(buf->data);

    if (p == NULL)
        return NULL;

    /* Allocate and initialize Command structure */
    my_command = (Command *) pg_malloc(sizeof(Command));
    initPQExpBuffer(&my_command->lines);
    appendPQExpBufferStr(&my_command->lines, p);
    my_command->first_line = NULL;  /* this is set later */
    my_command->type = SQL_COMMAND;
    my_command->meta = META_NONE;
    my_command->argc = 0;
    memset(my_command->argv, 0, sizeof(my_command->argv));
    my_command->varprefix = NULL;   /* allocated later, if needed */
    my_command->expr = NULL;
    initSimpleStats(&my_command->stats);

    return my_command;
}

/* Free a Command structure and associated data */
static void
free_command(Command *command)
{
    termPQExpBuffer(&command->lines);
    if (command->first_line)
        pg_free(command->first_line);
    for (int i = 0; i < command->argc; i++)
        pg_free(command->argv[i]);
    if (command->varprefix)
        pg_free(command->varprefix);

    /*
     * It should also free expr recursively, but this is currently not needed
     * as only gset commands (which do not have an expression) are freed.
     */
    pg_free(command);
}

/*
 * Once an SQL command is fully parsed, possibly by accumulating several
 * parts, complete other fields of the Command structure.
 */
static void
postprocess_sql_command(Command *my_command)
{
    char        buffer[128];

    Assert(my_command->type == SQL_COMMAND);

    /* Save the first line for error display. */
    strlcpy(buffer, my_command->lines.data, sizeof(buffer));
    buffer[strcspn(buffer, "\n\r")] = '\0';
    my_command->first_line = pg_strdup(buffer);

    /* parse query if necessary */
    switch (querymode)
    {
        case QUERY_SIMPLE:
            my_command->argv[0] = my_command->lines.data;
            my_command->argc++;
            break;
        case QUERY_EXTENDED:
        case QUERY_PREPARED:
            if (!parseQuery(my_command))
                exit(1);
            break;
        default:
            exit(1);
    }
}

/*
 * Parse a backslash command; return a Command struct, or NULL if comment
 *
 * At call, we have scanned only the initial backslash.
 */
static Command *
process_backslash_command(PsqlScanState sstate, const char *source)
{
    Command    *my_command;
    PQExpBufferData word_buf;
    int         word_offset;
    int         offsets[MAX_ARGS];  /* offsets of argument words */
    int         start_offset;
    int         lineno;
    int         j;

    initPQExpBuffer(&word_buf);

    /* Remember location of the backslash */
    start_offset = expr_scanner_offset(sstate) - 1;
    lineno = expr_scanner_get_lineno(sstate, start_offset);

    /* Collect first word of command */
    if (!expr_lex_one_word(sstate, &word_buf, &word_offset))
    {
        termPQExpBuffer(&word_buf);
        return NULL;
    }

    /* Allocate and initialize Command structure */
    my_command = (Command *) pg_malloc0(sizeof(Command));
    my_command->type = META_COMMAND;
    my_command->argc = 0;
    initSimpleStats(&my_command->stats);

    /* Save first word (command name) */
    j = 0;
    offsets[j] = word_offset;
    my_command->argv[j++] = pg_strdup(word_buf.data);
    my_command->argc++;

    /* ... and convert it to enum form */
    my_command->meta = getMetaCommand(my_command->argv[0]);

    if (my_command->meta == META_SET ||
        my_command->meta == META_IF ||
        my_command->meta == META_ELIF)
    {
        yyscan_t    yyscanner;

        /* For \set, collect var name */
        if (my_command->meta == META_SET)
        {
            if (!expr_lex_one_word(sstate, &word_buf, &word_offset))
                syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                             "missing argument", NULL, -1);

            offsets[j] = word_offset;
            my_command->argv[j++] = pg_strdup(word_buf.data);
            my_command->argc++;
        }

        /* then for all parse the expression */
        yyscanner = expr_scanner_init(sstate, source, lineno, start_offset,
                                      my_command->argv[0]);

        if (expr_yyparse(yyscanner) != 0)
        {
            /* dead code: exit done from syntax_error called by yyerror */
            exit(1);
        }

        my_command->expr = expr_parse_result;

        /* Save line, trimming any trailing newline */
        my_command->first_line =
            expr_scanner_get_substring(sstate,
                                       start_offset,
                                       expr_scanner_offset(sstate),
                                       true);

        expr_scanner_finish(yyscanner);

        termPQExpBuffer(&word_buf);

        return my_command;
    }

    /* For all other commands, collect remaining words. */
    while (expr_lex_one_word(sstate, &word_buf, &word_offset))
    {
        /*
         * my_command->argv[0] is the command itself, so the max number of
         * arguments is one less than MAX_ARGS
         */
        if (j >= MAX_ARGS)
            syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                         "too many arguments", NULL, -1);

        offsets[j] = word_offset;
        my_command->argv[j++] = pg_strdup(word_buf.data);
        my_command->argc++;
    }

    /* Save line, trimming any trailing newline */
    my_command->first_line =
        expr_scanner_get_substring(sstate,
                                   start_offset,
                                   expr_scanner_offset(sstate),
                                   true);

    if (my_command->meta == META_SLEEP)
    {
        if (my_command->argc < 2)
            syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                         "missing argument", NULL, -1);

        if (my_command->argc > 3)
            syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                         "too many arguments", NULL,
                         offsets[3] - start_offset);

        /*
         * Split argument into number and unit to allow "sleep 1ms" etc. We
         * don't have to terminate the number argument with null because it
         * will be parsed with atoi, which ignores trailing non-digit
         * characters.
         */
        if (my_command->argc == 2 && my_command->argv[1][0] != ':')
        {
            char       *c = my_command->argv[1];

            while (isdigit((unsigned char) *c))
                c++;
            if (*c)
            {
                my_command->argv[2] = c;
                offsets[2] = offsets[1] + (c - my_command->argv[1]);
                my_command->argc = 3;
            }
        }

        if (my_command->argc == 3)
        {
            if (pg_strcasecmp(my_command->argv[2], "us") != 0 &&
                pg_strcasecmp(my_command->argv[2], "ms") != 0 &&
                pg_strcasecmp(my_command->argv[2], "s") != 0)
                syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                             "unrecognized time unit, must be us, ms or s",
                             my_command->argv[2], offsets[2] - start_offset);
        }
    }
    else if (my_command->meta == META_SETSHELL)
    {
        if (my_command->argc < 3)
            syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                         "missing argument", NULL, -1);
    }
    else if (my_command->meta == META_SHELL)
    {
        if (my_command->argc < 2)
            syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                         "missing command", NULL, -1);
    }
    else if (my_command->meta == META_ELSE || my_command->meta == META_ENDIF)
    {
        if (my_command->argc != 1)
            syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                         "unexpected argument", NULL, -1);
    }
    else if (my_command->meta == META_GSET)
    {
        if (my_command->argc > 2)
            syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                         "too many arguments", NULL, -1);
    }
    else
    {
        /* my_command->meta == META_NONE */
        syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
                     "invalid command", NULL, -1);
    }

    termPQExpBuffer(&word_buf);

    return my_command;
}

static void
ConditionError(const char *desc, int cmdn, const char *msg)
{
    fprintf(stderr,
            "condition error in script \"%s\" command %d: %s\n",
            desc, cmdn, msg);
    exit(1);
}

/*
 * Partial evaluation of conditionals before recording and running the script.
 */
static void
CheckConditional(ParsedScript ps)
{
    /* statically check conditional structure */
    ConditionalStack cs = conditional_stack_create();
    int         i;

    for (i = 0; ps.commands[i] != NULL; i++)
    {
        Command    *cmd = ps.commands[i];

        if (cmd->type == META_COMMAND)
        {
            switch (cmd->meta)
            {
                case META_IF:
                    conditional_stack_push(cs, IFSTATE_FALSE);
                    break;
                case META_ELIF:
                    if (conditional_stack_empty(cs))
                        ConditionError(ps.desc, i + 1, "\\elif without matching \\if");
                    if (conditional_stack_peek(cs) == IFSTATE_ELSE_FALSE)
                        ConditionError(ps.desc, i + 1, "\\elif after \\else");
                    break;
                case META_ELSE:
                    if (conditional_stack_empty(cs))
                        ConditionError(ps.desc, i + 1, "\\else without matching \\if");
                    if (conditional_stack_peek(cs) == IFSTATE_ELSE_FALSE)
                        ConditionError(ps.desc, i + 1, "\\else after \\else");
                    conditional_stack_poke(cs, IFSTATE_ELSE_FALSE);
                    break;
                case META_ENDIF:
                    if (!conditional_stack_pop(cs))
                        ConditionError(ps.desc, i + 1, "\\endif without matching \\if");
                    break;
                default:
                    /* ignore anything else... */
                    break;
            }
        }
    }
    if (!conditional_stack_empty(cs))
        ConditionError(ps.desc, i + 1, "\\if without matching \\endif");
    conditional_stack_destroy(cs);
}

/*
 * Parse a script (either the contents of a file, or a built-in script)
 * and add it to the list of scripts.
 */
static void
ParseScript(const char *script, const char *desc, int weight)
{
    ParsedScript ps;
    PsqlScanState sstate;
    PQExpBufferData line_buf;
    int         alloc_num;
    int         index;
    int         lineno;
    int         start_offset;

#define COMMANDS_ALLOC_NUM 128
    alloc_num = COMMANDS_ALLOC_NUM;

    /* Initialize all fields of ps */
    ps.desc = desc;
    ps.weight = weight;
    ps.commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
    initStats(&ps.stats, 0);

    /* Prepare to parse script */
    sstate = psql_scan_create(&pgbench_callbacks);

    /*
     * Ideally, we'd scan scripts using the encoding and stdstrings settings
     * we get from a DB connection.  However, without major rearrangement of
     * pgbench's argument parsing, we can't have a DB connection at the time
     * we parse scripts.  Using SQL_ASCII (encoding 0) should work well enough
     * with any backend-safe encoding, though conceivably we could be fooled
     * if a script file uses a client-only encoding.  We also assume that
     * stdstrings should be true, which is a bit riskier.
     */
    psql_scan_setup(sstate, script, strlen(script), 0, true);
    start_offset = expr_scanner_offset(sstate) - 1;

    initPQExpBuffer(&line_buf);

    index = 0;

    for (;;)
    {
        PsqlScanResult sr;
        promptStatus_t prompt;
        Command    *command = NULL;

        resetPQExpBuffer(&line_buf);
        lineno = expr_scanner_get_lineno(sstate, start_offset);

        sr = psql_scan(sstate, &line_buf, &prompt);

        /* If we collected a new SQL command, process that */
        command = create_sql_command(&line_buf, desc);

        /* store new command */
        if (command)
            ps.commands[index++] = command;

        /* If we reached a backslash, process that */
        if (sr == PSCAN_BACKSLASH)
        {
            command = process_backslash_command(sstate, desc);

            if (command)
            {
                /*
                 * If this is gset, merge into the preceding command. (We
                 * don't use a command slot in this case).
                 */
                if (command->meta == META_GSET)
                {
                    Command    *cmd;

                    if (index == 0)
                        syntax_error(desc, lineno, NULL, NULL,
                                     "\\gset must follow a SQL command",
                                     NULL, -1);

                    cmd = ps.commands[index - 1];

                    if (cmd->type != SQL_COMMAND ||
                        cmd->varprefix != NULL)
                        syntax_error(desc, lineno, NULL, NULL,
                                     "\\gset must follow a SQL command",
                                     cmd->first_line, -1);

                    /* get variable prefix */
                    if (command->argc <= 1 || command->argv[1][0] == '\0')
                        cmd->varprefix = pg_strdup("");
                    else
                        cmd->varprefix = pg_strdup(command->argv[1]);

                    /* cleanup unused command */
                    free_command(command);

                    continue;
                }

                /* Attach any other backslash command as a new command */
                ps.commands[index++] = command;
            }
        }

        /*
         * Since we used a command slot, allocate more if needed.  Note we
         * always allocate one more in order to accommodate the NULL
         * terminator below.
         */
        if (index >= alloc_num)
        {
            alloc_num += COMMANDS_ALLOC_NUM;
            ps.commands = (Command **)
                pg_realloc(ps.commands, sizeof(Command *) * alloc_num);
        }

        /* Done if we reached EOF */
        if (sr == PSCAN_INCOMPLETE || sr == PSCAN_EOL)
            break;
    }

    ps.commands[index] = NULL;

    addScript(ps);

    termPQExpBuffer(&line_buf);
    psql_scan_finish(sstate);
    psql_scan_destroy(sstate);
}

/*
 * Read the entire contents of file fd, and return it in a malloc'd buffer.
 *
 * The buffer will typically be larger than necessary, but we don't care
 * in this program, because we'll free it as soon as we've parsed the script.
 */
static char *
read_file_contents(FILE *fd)
{
    char       *buf;
    size_t      buflen = BUFSIZ;
    size_t      used = 0;

    buf = (char *) pg_malloc(buflen);

    for (;;)
    {
        size_t      nread;

        nread = fread(buf + used, 1, BUFSIZ, fd);
        used += nread;
        /* If fread() read less than requested, must be EOF or error */
        if (nread < BUFSIZ)
            break;
        /* Enlarge buf so we can read some more */
        buflen += BUFSIZ;
        buf = (char *) pg_realloc(buf, buflen);
    }
    /* There is surely room for a terminator */
    buf[used] = '\0';

    return buf;
}

/*
 * Given a file name, read it and add its script to the list.
 * "-" means to read stdin.
 * NB: filename must be storage that won't disappear.
 */
static void
process_file(const char *filename, int weight)
{
    FILE       *fd;
    char       *buf;

    /* Slurp the file contents into "buf" */
    if (strcmp(filename, "-") == 0)
        fd = stdin;
    else if ((fd = fopen(filename, "r")) == NULL)
    {
        fprintf(stderr, "could not open file \"%s\": %s\n",
                filename, strerror(errno));
        exit(1);
    }

    buf = read_file_contents(fd);

    if (ferror(fd))
    {
        fprintf(stderr, "could not read file \"%s\": %s\n",
                filename, strerror(errno));
        exit(1);
    }

    if (fd != stdin)
        fclose(fd);

    ParseScript(buf, filename, weight);

    free(buf);
}

/* Parse the given builtin script and add it to the list. */
static void
process_builtin(const BuiltinScript *bi, int weight)
{
    ParseScript(bi->script, bi->desc, weight);
}

/* show available builtin scripts */
static void
listAvailableScripts(void)
{
    int         i;

    fprintf(stderr, "Available builtin scripts:\n");
    for (i = 0; i < lengthof(builtin_script); i++)
        fprintf(stderr, "  %13s: %s\n", builtin_script[i].name, builtin_script[i].desc);
    fprintf(stderr, "\n");
}

/* return builtin script "name" if unambiguous, fails if not found */
static const BuiltinScript *
findBuiltin(const char *name)
{
    int         i,
                found = 0,
                len = strlen(name);
    const BuiltinScript *result = NULL;

    for (i = 0; i < lengthof(builtin_script); i++)
    {
        if (strncmp(builtin_script[i].name, name, len) == 0)
        {
            result = &builtin_script[i];
            found++;
        }
    }

    /* ok, unambiguous result */
    if (found == 1)
        return result;

    /* error cases */
    if (found == 0)
        fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
    else                        /* found > 1 */
        fprintf(stderr,
                "ambiguous builtin name: %d builtin scripts found for prefix \"%s\"\n", found, name);

    listAvailableScripts();
    exit(1);
}

/*
 * Determine the weight specification from a script option (-b, -f), if any,
 * and return it as an integer (1 is returned if there's no weight).  The
 * script name is returned in *script as a malloc'd string.
 */
static int
parseScriptWeight(const char *option, char **script)
{
    char       *sep;
    int         weight;

    if ((sep = strrchr(option, WSEP)))
    {
        int         namelen = sep - option;
        long        wtmp;
        char       *badp;

        /* generate the script name */
        *script = pg_malloc(namelen + 1);
        strncpy(*script, option, namelen);
        (*script)[namelen] = '\0';

        /* process digits of the weight spec */
        errno = 0;
        wtmp = strtol(sep + 1, &badp, 10);
        if (errno != 0 || badp == sep + 1 || *badp != '\0')
        {
            fprintf(stderr, "invalid weight specification: %s\n", sep);
            exit(1);
        }
        if (wtmp > INT_MAX || wtmp < 0)
        {
            fprintf(stderr,
                    "weight specification out of range (0 .. %u): " INT64_FORMAT "\n",
                    INT_MAX, (int64) wtmp);
            exit(1);
        }
        weight = wtmp;
    }
    else
    {
        *script = pg_strdup(option);
        weight = 1;
    }

    return weight;
}

/* append a script to the list of scripts to process */
static void
addScript(ParsedScript script)
{
    if (script.commands == NULL || script.commands[0] == NULL)
    {
        fprintf(stderr, "empty command list for script \"%s\"\n", script.desc);
        exit(1);
    }

    if (num_scripts >= MAX_SCRIPTS)
    {
        fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
        exit(1);
    }

    CheckConditional(script);

    sql_script[num_scripts] = script;
    num_scripts++;
}

/*
 * Print progress report.
 *
 * On entry, *last and *last_report contain the statistics and time of last
 * progress report.  On exit, they are updated with the new stats.
 */
static void
printProgressReport(TState *threads, int64 test_start, int64 now,
                    StatsData *last, int64 *last_report)
{
    /* generate and show report */
    int64       run = now - *last_report,
                ntx;
    double      tps,
                total_run,
                latency,
                sqlat,
                lag,
                stdev;
    char        tbuf[315];
    StatsData   cur;

    /*
     * Add up the statistics of all threads.
     *
     * XXX: No locking.  There is no guarantee that we get an atomic snapshot
     * of the transaction count and latencies, so these figures can well be
     * off by a small amount.  The progress report's purpose is to give a
     * quick overview of how the test is going, so that shouldn't matter too
     * much.  (If a read from a 64-bit integer is not atomic, you might get a
     * "torn" read and completely bogus latencies though!)
     */
    initStats(&cur, 0);
    for (int i = 0; i < nthreads; i++)
    {
        mergeSimpleStats(&cur.latency, &threads[i].stats.latency);
        mergeSimpleStats(&cur.lag, &threads[i].stats.lag);
        cur.cnt += threads[i].stats.cnt;
        cur.skipped += threads[i].stats.skipped;
    }

    /* we count only actually executed transactions */
    ntx = (cur.cnt - cur.skipped) - (last->cnt - last->skipped);
    total_run = (now - test_start) / 1000000.0;
    tps = 1000000.0 * ntx / run;
    if (ntx > 0)
    {
        latency = 0.001 * (cur.latency.sum - last->latency.sum) / ntx;
        sqlat = 1.0 * (cur.latency.sum2 - last->latency.sum2) / ntx;
        stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
        lag = 0.001 * (cur.lag.sum - last->lag.sum) / ntx;
    }
    else
    {
        latency = sqlat = stdev = lag = 0;
    }

    if (progress_timestamp)
    {
        /*
         * On some platforms the current system timestamp is available in
         * now_time, but rather than get entangled with that, we just eat the
         * cost of an extra syscall in all cases.
         */
        struct timeval tv;

        gettimeofday(&tv, NULL);
        snprintf(tbuf, sizeof(tbuf), "%ld.%03ld s",
                 (long) tv.tv_sec, (long) (tv.tv_usec / 1000));
    }
    else
    {
        /* round seconds are expected, but the thread may be late */
        snprintf(tbuf, sizeof(tbuf), "%.1f s", total_run);
    }

    fprintf(stderr,
            "progress: %s, %.1f tps, lat %.3f ms stddev %.3f",
            tbuf, tps, latency, stdev);

    if (throttle_delay)
    {
        fprintf(stderr, ", lag %.3f ms", lag);
        if (latency_limit)
            fprintf(stderr, ", " INT64_FORMAT " skipped",
                    cur.skipped - last->skipped);
    }
    fprintf(stderr, "\n");

    *last = cur;
    *last_report = now;
}

static void
printSimpleStats(const char *prefix, SimpleStats *ss)
{
    if (ss->count > 0)
    {
        double      latency = ss->sum / ss->count;
        double      stddev = sqrt(ss->sum2 / ss->count - latency * latency);

        printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
        printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
    }
}

/* print out results */
static void
printResults(StatsData *total, instr_time total_time,
             instr_time conn_total_time, int64 latency_late)
{
    double      time_include,
                tps_include,
                tps_exclude;
    int64       ntx = total->cnt - total->skipped;

    time_include = INSTR_TIME_GET_DOUBLE(total_time);

    /* tps is about actually executed transactions */
    tps_include = ntx / time_include;
    tps_exclude = ntx /
        (time_include - (INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));

    /* Report test parameters. */
    printf("transaction type: %s\n",
           num_scripts == 1 ? sql_script[0].desc : "multiple scripts");
    printf("scaling factor: %d\n", scale);
    /* only print partitioning information if some partitioning was detected */
    if (partition_method != PART_NONE)
        printf("partition method: %s\npartitions: %d\n",
               PARTITION_METHOD[partition_method], partitions);
    printf("query mode: %s\n", QUERYMODE[querymode]);
    printf("number of clients: %d\n", nclients);
    printf("number of threads: %d\n", nthreads);
    if (duration <= 0)
    {
        printf("number of transactions per client: %d\n", nxacts);
        printf("number of transactions actually processed: " INT64_FORMAT "/%d\n",
               ntx, nxacts * nclients);
    }
    else
    {
        printf("duration: %d s\n", duration);
        printf("number of transactions actually processed: " INT64_FORMAT "\n",
               ntx);
    }

    /* Remaining stats are nonsensical if we failed to execute any xacts */
    if (total->cnt <= 0)
        return;

    if (throttle_delay && latency_limit)
        printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
               total->skipped,
               100.0 * total->skipped / total->cnt);

    if (latency_limit)
        printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT "/" INT64_FORMAT " (%.3f %%)\n",
               latency_limit / 1000.0, latency_late, ntx,
               (ntx > 0) ? 100.0 * latency_late / ntx : 0.0);

    if (throttle_delay || progress || latency_limit)
        printSimpleStats("latency", &total->latency);
    else
    {
        /* no measurement, show average latency computed from run time */
        printf("latency average = %.3f ms\n",
               1000.0 * time_include * nclients / total->cnt);
    }

    if (throttle_delay)
    {
        /*
         * Report average transaction lag under rate limit throttling.  This
         * is the delay between scheduled and actual start times for the
         * transaction.  The measured lag may be caused by thread/client load,
         * the database load, or the Poisson throttling process.
         */
        printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
               0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
    }

    printf("tps = %f (including connections establishing)\n", tps_include);
    printf("tps = %f (excluding connections establishing)\n", tps_exclude);

    /* Report per-script/command statistics */
    if (per_script_stats || report_per_command)
    {
        int         i;

        for (i = 0; i < num_scripts; i++)
        {
            if (per_script_stats)
            {
                StatsData  *sstats = &sql_script[i].stats;

                printf("SQL script %d: %s\n"
                       " - weight: %d (targets %.1f%% of total)\n"
                       " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
                       i + 1, sql_script[i].desc,
                       sql_script[i].weight,
                       100.0 * sql_script[i].weight / total_weight,
                       sstats->cnt,
                       100.0 * sstats->cnt / total->cnt,
                       (sstats->cnt - sstats->skipped) / time_include);

                if (throttle_delay && latency_limit && sstats->cnt > 0)
                    printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
                           sstats->skipped,
                           100.0 * sstats->skipped / sstats->cnt);

                printSimpleStats(" - latency", &sstats->latency);
            }

            /* Report per-command latencies */
            if (report_per_command)
            {
                Command   **commands;

                if (per_script_stats)
                    printf(" - statement latencies in milliseconds:\n");
                else
                    printf("statement latencies in milliseconds:\n");

                for (commands = sql_script[i].commands;
                     *commands != NULL;
                     commands++)
                {
                    SimpleStats *cstats = &(*commands)->stats;

                    printf("   %11.3f  %s\n",
                           (cstats->count > 0) ?
                           1000.0 * cstats->sum / cstats->count : 0.0,
                           (*commands)->first_line);
                }
            }
        }
    }
}

/*
 * Set up a random seed according to seed parameter (NULL means default),
 * and initialize base_random_sequence for use in initializing other sequences.
 */
static bool
set_random_seed(const char *seed)
{
    uint64      iseed;

    if (seed == NULL || strcmp(seed, "time") == 0)
    {
        /* rely on current time */
        instr_time  now;

        INSTR_TIME_SET_CURRENT(now);
        iseed = (uint64) INSTR_TIME_GET_MICROSEC(now);
    }
    else if (strcmp(seed, "rand") == 0)
    {
        /* use some "strong" random source */
        if (!pg_strong_random(&iseed, sizeof(iseed)))
        {
            fprintf(stderr, "could not generate random seed.\n");
            return false;
        }
    }
    else
    {
        /* parse unsigned-int seed value */
        unsigned long ulseed;
        char        garbage;

        /* Don't try to use UINT64_FORMAT here; it might not work for sscanf */
        if (sscanf(seed, "%lu%c", &ulseed, &garbage) != 1)
        {
            fprintf(stderr,
                    "unrecognized random seed option \"%s\": expecting an unsigned integer, \"time\" or \"rand\"\n",
                    seed);
            return false;
        }
        iseed = (uint64) ulseed;
    }

    if (seed != NULL)
        fprintf(stderr, "setting random seed to " UINT64_FORMAT "\n", iseed);
    random_seed = iseed;

    /* Fill base_random_sequence with low-order bits of seed */
    base_random_sequence.xseed[0] = iseed & 0xFFFF;
    base_random_sequence.xseed[1] = (iseed >> 16) & 0xFFFF;
    base_random_sequence.xseed[2] = (iseed >> 32) & 0xFFFF;

    return true;
}

int
main(int argc, char **argv)
{
    static struct option long_options[] = {
        /* systematic long/short named options */
        {"builtin", required_argument, NULL, 'b'},
        {"client", required_argument, NULL, 'c'},
        {"connect", no_argument, NULL, 'C'},
        {"debug", no_argument, NULL, 'd'},
        {"define", required_argument, NULL, 'D'},
        {"file", required_argument, NULL, 'f'},
        {"fillfactor", required_argument, NULL, 'F'},
        {"host", required_argument, NULL, 'h'},
        {"initialize", no_argument, NULL, 'i'},
        {"init-steps", required_argument, NULL, 'I'},
        {"jobs", required_argument, NULL, 'j'},
        {"log", no_argument, NULL, 'l'},
        {"latency-limit", required_argument, NULL, 'L'},
        {"no-vacuum", no_argument, NULL, 'n'},
        {"port", required_argument, NULL, 'p'},
        {"progress", required_argument, NULL, 'P'},
        {"protocol", required_argument, NULL, 'M'},
        {"quiet", no_argument, NULL, 'q'},
        {"report-latencies", no_argument, NULL, 'r'},
        {"rate", required_argument, NULL, 'R'},
        {"scale", required_argument, NULL, 's'},
        {"select-only", no_argument, NULL, 'S'},
        {"skip-some-updates", no_argument, NULL, 'N'},
        {"time", required_argument, NULL, 'T'},
        {"transactions", required_argument, NULL, 't'},
        {"username", required_argument, NULL, 'U'},
        {"vacuum-all", no_argument, NULL, 'v'},
        /* long-named only options */
        {"unlogged-tables", no_argument, NULL, 1},
        {"tablespace", required_argument, NULL, 2},
        {"index-tablespace", required_argument, NULL, 3},
        {"sampling-rate", required_argument, NULL, 4},
        {"aggregate-interval", required_argument, NULL, 5},
        {"progress-timestamp", no_argument, NULL, 6},
        {"log-prefix", required_argument, NULL, 7},
        {"foreign-keys", no_argument, NULL, 8},
        {"random-seed", required_argument, NULL, 9},
        {"show-script", required_argument, NULL, 10},
        {"partitions", required_argument, NULL, 11},
        {"partition-method", required_argument, NULL, 12},
        {NULL, 0, NULL, 0}
    };

    int         c;
    bool        is_init_mode = false;   /* initialize mode? */
    char       *initialize_steps = NULL;
    bool        foreign_keys = false;
    bool        is_no_vacuum = false;
    bool        do_vacuum_accounts = false; /* vacuum accounts table? */
    int         optindex;
    bool        scale_given = false;

    bool        benchmarking_option_set = false;
    bool        initialization_option_set = false;
    bool        internal_script_used = false;

    CState     *state;          /* status of clients */
    TState     *threads;        /* array of thread */

    instr_time  start_time;     /* start up time */
    instr_time  total_time;
    instr_time  conn_total_time;
    int64       latency_late = 0;
    StatsData   stats;
    int         weight;

    int         i;
    int         nclients_dealt;

#ifdef HAVE_GETRLIMIT
    struct rlimit rlim;
#endif

    PGconn     *con;
    char       *env;

    int         exit_code = 0;

    pg_logging_init(argv[0]);
    progname = get_progname(argv[0]);

    if (argc > 1)
    {
        if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
        {
            usage();
            exit(0);
        }
        if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
        {
            puts("pgbench (PostgreSQL) " PG_VERSION);
            exit(0);
        }
    }

    if ((env = getenv("PGHOST")) != NULL && *env != '\0')
        pghost = env;
    if ((env = getenv("PGPORT")) != NULL && *env != '\0')
        pgport = env;
    else if ((env = getenv("PGUSER")) != NULL && *env != '\0')
        login = env;

    state = (CState *) pg_malloc0(sizeof(CState));

    /* set random seed early, because it may be used while parsing scripts. */
    if (!set_random_seed(getenv("PGBENCH_RANDOM_SEED")))
    {
        fprintf(stderr, "error while setting random seed from PGBENCH_RANDOM_SEED environment variable\n");
        exit(1);
    }

    while ((c = getopt_long(argc, argv, "iI:h:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
    {
        char       *script;

        switch (c)
        {
            case 'i':
                is_init_mode = true;
                break;
            case 'I':
                if (initialize_steps)
                    pg_free(initialize_steps);
                initialize_steps = pg_strdup(optarg);
                checkInitSteps(initialize_steps);
                initialization_option_set = true;
                break;
            case 'h':
                pghost = pg_strdup(optarg);
                break;
            case 'n':
                is_no_vacuum = true;
                break;
            case 'v':
                benchmarking_option_set = true;
                do_vacuum_accounts = true;
                break;
            case 'p':
                pgport = pg_strdup(optarg);
                break;
            case 'd':
                debug++;
                break;
            case 'c':
                benchmarking_option_set = true;
                nclients = atoi(optarg);
                if (nclients <= 0)
                {
                    fprintf(stderr, "invalid number of clients: \"%s\"\n",
                            optarg);
                    exit(1);
                }
#ifdef HAVE_GETRLIMIT
#ifdef RLIMIT_NOFILE            /* most platforms use RLIMIT_NOFILE */
                if (getrlimit(RLIMIT_NOFILE, &rlim) == -1)
#else                           /* but BSD doesn't ... */
                if (getrlimit(RLIMIT_OFILE, &rlim) == -1)
#endif                          /* RLIMIT_NOFILE */
                {
                    fprintf(stderr, "getrlimit failed: %s\n", strerror(errno));
                    exit(1);
                }
                if (rlim.rlim_cur < nclients + 3)
                {
                    fprintf(stderr, "need at least %d open files, but system limit is %ld\n",
                            nclients + 3, (long) rlim.rlim_cur);
                    fprintf(stderr, "Reduce number of clients, or use limit/ulimit to increase the system limit.\n");
                    exit(1);
                }
#endif                          /* HAVE_GETRLIMIT */
                break;
            case 'j':           /* jobs */
                benchmarking_option_set = true;
                nthreads = atoi(optarg);
                if (nthreads <= 0)
                {
                    fprintf(stderr, "invalid number of threads: \"%s\"\n",
                            optarg);
                    exit(1);
                }
#ifndef ENABLE_THREAD_SAFETY
                if (nthreads != 1)
                {
                    fprintf(stderr, "threads are not supported on this platform; use -j1\n");
                    exit(1);
                }
#endif                          /* !ENABLE_THREAD_SAFETY */
                break;
            case 'C':
                benchmarking_option_set = true;
                is_connect = true;
                break;
            case 'r':
                benchmarking_option_set = true;
                report_per_command = true;
                break;
            case 's':
                scale_given = true;
                scale = atoi(optarg);
                if (scale <= 0)
                {
                    fprintf(stderr, "invalid scaling factor: \"%s\"\n", optarg);
                    exit(1);
                }
                break;
            case 't':
                benchmarking_option_set = true;
                nxacts = atoi(optarg);
                if (nxacts <= 0)
                {
                    fprintf(stderr, "invalid number of transactions: \"%s\"\n",
                            optarg);
                    exit(1);
                }
                break;
            case 'T':
                benchmarking_option_set = true;
                duration = atoi(optarg);
                if (duration <= 0)
                {
                    fprintf(stderr, "invalid duration: \"%s\"\n", optarg);
                    exit(1);
                }
                break;
            case 'U':
                login = pg_strdup(optarg);
                break;
            case 'l':
                benchmarking_option_set = true;
                use_log = true;
                break;
            case 'q':
                initialization_option_set = true;
                use_quiet = true;
                break;
            case 'b':
                if (strcmp(optarg, "list") == 0)
                {
                    listAvailableScripts();
                    exit(0);
                }
                weight = parseScriptWeight(optarg, &script);
                process_builtin(findBuiltin(script), weight);
                benchmarking_option_set = true;
                internal_script_used = true;
                break;
            case 'S':
                process_builtin(findBuiltin("select-only"), 1);
                benchmarking_option_set = true;
                internal_script_used = true;
                break;
            case 'N':
                process_builtin(findBuiltin("simple-update"), 1);
                benchmarking_option_set = true;
                internal_script_used = true;
                break;
            case 'f':
                weight = parseScriptWeight(optarg, &script);
                process_file(script, weight);
                benchmarking_option_set = true;
                break;
            case 'D':
                {
                    char       *p;

                    benchmarking_option_set = true;

                    if ((p = strchr(optarg, '=')) == NULL || p == optarg || *(p + 1) == '\0')
                    {
                        fprintf(stderr, "invalid variable definition: \"%s\"\n",
                                optarg);
                        exit(1);
                    }

                    *p++ = '\0';
                    if (!putVariable(&state[0], "option", optarg, p))
                        exit(1);
                }
                break;
            case 'F':
                initialization_option_set = true;
                fillfactor = atoi(optarg);
                if (fillfactor < 10 || fillfactor > 100)
                {
                    fprintf(stderr, "invalid fillfactor: \"%s\"\n", optarg);
                    exit(1);
                }
                break;
            case 'M':
                benchmarking_option_set = true;
                for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
                    if (strcmp(optarg, QUERYMODE[querymode]) == 0)
                        break;
                if (querymode >= NUM_QUERYMODE)
                {
                    fprintf(stderr, "invalid query mode (-M): \"%s\"\n",
                            optarg);
                    exit(1);
                }
                break;
            case 'P':
                benchmarking_option_set = true;
                progress = atoi(optarg);
                if (progress <= 0)
                {
                    fprintf(stderr, "invalid thread progress delay: \"%s\"\n",
                            optarg);
                    exit(1);
                }
                break;
            case 'R':
                {
                    /* get a double from the beginning of option value */
                    double      throttle_value = atof(optarg);

                    benchmarking_option_set = true;

                    if (throttle_value <= 0.0)
                    {
                        fprintf(stderr, "invalid rate limit: \"%s\"\n", optarg);
                        exit(1);
                    }
                    /* Invert rate limit into per-transaction delay in usec */
                    throttle_delay = 1000000.0 / throttle_value;
                }
                break;
            case 'L':
                {
                    double      limit_ms = atof(optarg);

                    if (limit_ms <= 0.0)
                    {
                        fprintf(stderr, "invalid latency limit: \"%s\"\n",
                                optarg);
                        exit(1);
                    }
                    benchmarking_option_set = true;
                    latency_limit = (int64) (limit_ms * 1000);
                }
                break;
            case 1:             /* unlogged-tables */
                initialization_option_set = true;
                unlogged_tables = true;
                break;
            case 2:             /* tablespace */
                initialization_option_set = true;
                tablespace = pg_strdup(optarg);
                break;
            case 3:             /* index-tablespace */
                initialization_option_set = true;
                index_tablespace = pg_strdup(optarg);
                break;
            case 4:             /* sampling-rate */
                benchmarking_option_set = true;
                sample_rate = atof(optarg);
                if (sample_rate <= 0.0 || sample_rate > 1.0)
                {
                    fprintf(stderr, "invalid sampling rate: \"%s\"\n", optarg);
                    exit(1);
                }
                break;
            case 5:             /* aggregate-interval */
                benchmarking_option_set = true;
                agg_interval = atoi(optarg);
                if (agg_interval <= 0)
                {
                    fprintf(stderr, "invalid number of seconds for aggregation: \"%s\"\n",
                            optarg);
                    exit(1);
                }
                break;
            case 6:             /* progress-timestamp */
                progress_timestamp = true;
                benchmarking_option_set = true;
                break;
            case 7:             /* log-prefix */
                benchmarking_option_set = true;
                logfile_prefix = pg_strdup(optarg);
                break;
            case 8:             /* foreign-keys */
                initialization_option_set = true;
                foreign_keys = true;
                break;
            case 9:             /* random-seed */
                benchmarking_option_set = true;
                if (!set_random_seed(optarg))
                {
                    fprintf(stderr, "error while setting random seed from --random-seed option\n");
                    exit(1);
                }
                break;
            case 10:            /* list */
                {
                    const BuiltinScript *s = findBuiltin(optarg);

                    fprintf(stderr, "-- %s: %s\n%s\n", s->name, s->desc, s->script);
                    exit(0);
                }
                break;
            case 11:            /* partitions */
                initialization_option_set = true;
                partitions = atoi(optarg);
                if (partitions < 0)
                {
                    fprintf(stderr, "invalid number of partitions: \"%s\"\n",
                            optarg);
                    exit(1);
                }
                break;
            case 12:            /* partition-method */
                initialization_option_set = true;
                if (pg_strcasecmp(optarg, "range") == 0)
                    partition_method = PART_RANGE;
                else if (pg_strcasecmp(optarg, "hash") == 0)
                    partition_method = PART_HASH;
                else
                {
                    fprintf(stderr, "invalid partition method, expecting \"range\" or \"hash\","
                            " got: \"%s\"\n", optarg);
                    exit(1);
                }
                break;
            default:
                fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
                exit(1);
                break;
        }
    }

    /* set default script if none */
    if (num_scripts == 0 && !is_init_mode)
    {
        process_builtin(findBuiltin("tpcb-like"), 1);
        benchmarking_option_set = true;
        internal_script_used = true;
    }

    /* complete SQL command initialization and compute total weight */
    for (i = 0; i < num_scripts; i++)
    {
        Command   **commands = sql_script[i].commands;

        for (int j = 0; commands[j] != NULL; j++)
            if (commands[j]->type == SQL_COMMAND)
                postprocess_sql_command(commands[j]);

        /* cannot overflow: weight is 32b, total_weight 64b */
        total_weight += sql_script[i].weight;
    }

    if (total_weight == 0 && !is_init_mode)
    {
        fprintf(stderr, "total script weight must not be zero\n");
        exit(1);
    }

    /* show per script stats if several scripts are used */
    if (num_scripts > 1)
        per_script_stats = true;

    /*
     * Don't need more threads than there are clients.  (This is not merely an
     * optimization; throttle_delay is calculated incorrectly below if some
     * threads have no clients assigned to them.)
     */
    if (nthreads > nclients)
        nthreads = nclients;

    /*
     * Convert throttle_delay to a per-thread delay time.  Note that this
     * might be a fractional number of usec, but that's OK, since it's just
     * the center of a Poisson distribution of delays.
     */
    throttle_delay *= nthreads;

    if (argc > optind)
        dbName = argv[optind++];
    else
    {
        if ((env = getenv("PGDATABASE")) != NULL && *env != '\0')
            dbName = env;
        else if (login != NULL && *login != '\0')
            dbName = login;
        else
            dbName = "";
    }

    if (optind < argc)
    {
        fprintf(stderr, _("%s: too many command-line arguments (first is \"%s\")\n"),
                progname, argv[optind]);
        fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
        exit(1);
    }

    if (is_init_mode)
    {
        if (benchmarking_option_set)
        {
            fprintf(stderr, "some of the specified options cannot be used in initialization (-i) mode\n");
            exit(1);
        }

        if (partitions == 0 && partition_method != PART_NONE)
        {
            fprintf(stderr, "--partition-method requires greater than zero --partitions\n");
            exit(1);
        }