pg_amcheck.c

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/*-------------------------------------------------------------------------
 *
 * pg_amcheck.c
 *      Detects corruption within database relations.
 *
 * Copyright (c) 2017-2023, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *    src/bin/pg_amcheck/pg_amcheck.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres_fe.h"
 
#include <limits.h>
#include <time.h>
 
#include "catalog/pg_am_d.h"
#include "catalog/pg_namespace_d.h"
#include "common/logging.h"
#include "common/username.h"
#include "fe_utils/cancel.h"
#include "fe_utils/option_utils.h"
#include "fe_utils/parallel_slot.h"
#include "fe_utils/query_utils.h"
#include "fe_utils/simple_list.h"
#include "fe_utils/string_utils.h"
#include "getopt_long.h"        /* pgrminclude ignore */
#include "pgtime.h"
#include "storage/block.h"
 
typedef struct PatternInfo
{
    const char *pattern;        /* Unaltered pattern from the command line */
    char       *db_regex;       /* Database regexp parsed from pattern, or
                                 * NULL */
    char       *nsp_regex;      /* Schema regexp parsed from pattern, or NULL */
    char       *rel_regex;      /* Relation regexp parsed from pattern, or
                                 * NULL */
    bool        heap_only;      /* true if rel_regex should only match heap
                                 * tables */
    bool        btree_only;     /* true if rel_regex should only match btree
                                 * indexes */
    bool        matched;        /* true if the pattern matched in any database */
} PatternInfo;
 
typedef struct PatternInfoArray
{
    PatternInfo *data;
    size_t      len;
} PatternInfoArray;
 
/* pg_amcheck command line options controlled by user flags */
typedef struct AmcheckOptions
{
    bool        dbpattern;
    bool        alldb;
    bool        echo;
    bool        verbose;
    bool        strict_names;
    bool        show_progress;
    int         jobs;
 
    /*
     * Whether to install missing extensions, and optionally the name of the
     * schema in which to install the extension's objects.
     */
    bool        install_missing;
    char       *install_schema;
 
    /* Objects to check or not to check, as lists of PatternInfo structs. */
    PatternInfoArray include;
    PatternInfoArray exclude;
 
    /*
     * As an optimization, if any pattern in the exclude list applies to heap
     * tables, or similarly if any such pattern applies to btree indexes, or
     * to schemas, then these will be true, otherwise false.  These should
     * always agree with what you'd conclude by grep'ing through the exclude
     * list.
     */
    bool        excludetbl;
    bool        excludeidx;
    bool        excludensp;
 
    /*
     * If any inclusion pattern exists, then we should only be checking
     * matching relations rather than all relations, so this is true iff
     * include is empty.
     */
    bool        allrel;
 
    /* heap table checking options */
    bool        no_toast_expansion;
    bool        reconcile_toast;
    bool        on_error_stop;
    int64       startblock;
    int64       endblock;
    const char *skip;
 
    /* btree index checking options */
    bool        parent_check;
    bool        rootdescend;
    bool        heapallindexed;
 
    /* heap and btree hybrid option */
    bool        no_btree_expansion;
} AmcheckOptions;
 
static AmcheckOptions opts = {
    .dbpattern = false,
    .alldb = false,
    .echo = false,
    .verbose = false,
    .strict_names = true,
    .show_progress = false,
    .jobs = 1,
    .install_missing = false,
    .install_schema = "pg_catalog",
    .include = {NULL, 0},
    .exclude = {NULL, 0},
    .excludetbl = false,
    .excludeidx = false,
    .excludensp = false,
    .allrel = true,
    .no_toast_expansion = false,
    .reconcile_toast = true,
    .on_error_stop = false,
    .startblock = -1,
    .endblock = -1,
    .skip = "none",
    .parent_check = false,
    .rootdescend = false,
    .heapallindexed = false,
    .no_btree_expansion = false
};
 
static const char *progname = NULL;
 
/* Whether all relations have so far passed their corruption checks */
static bool all_checks_pass = true;
 
/* Time last progress report was displayed */
static pg_time_t last_progress_report = 0;
static bool progress_since_last_stderr = false;
 
typedef struct DatabaseInfo
{
    char       *datname;
    char       *amcheck_schema; /* escaped, quoted literal */
} DatabaseInfo;
 
typedef struct RelationInfo
{
    const DatabaseInfo *datinfo;    /* shared by other relinfos */
    Oid         reloid;
    bool        is_heap;        /* true if heap, false if btree */
    char       *nspname;
    char       *relname;
    int         relpages;
    int         blocks_to_check;
    char       *sql;            /* set during query run, pg_free'd after */
} RelationInfo;
 
/*
 * Query for determining if contrib's amcheck is installed.  If so, selects the
 * namespace name where amcheck's functions can be found.
 */
static const char *amcheck_sql =
"SELECT n.nspname, x.extversion FROM pg_catalog.pg_extension x"
"\nJOIN pg_catalog.pg_namespace n ON x.extnamespace = n.oid"
"\nWHERE x.extname = 'amcheck'";
 
static void prepare_heap_command(PQExpBuffer sql, RelationInfo *rel,
                                 PGconn *conn);
static void prepare_btree_command(PQExpBuffer sql, RelationInfo *rel,
                                  PGconn *conn);
static void run_command(ParallelSlot *slot, const char *sql);
static bool verify_heap_slot_handler(PGresult *res, PGconn *conn,
                                     void *context);
static bool verify_btree_slot_handler(PGresult *res, PGconn *conn, void *context);
static void help(const char *progname);
static void progress_report(uint64 relations_total, uint64 relations_checked,
                            uint64 relpages_total, uint64 relpages_checked,
                            const char *datname, bool force, bool finished);
 
static void append_database_pattern(PatternInfoArray *pia, const char *pattern,
                                    int encoding);
static void append_schema_pattern(PatternInfoArray *pia, const char *pattern,
                                  int encoding);
static void append_relation_pattern(PatternInfoArray *pia, const char *pattern,
                                    int encoding);
static void append_heap_pattern(PatternInfoArray *pia, const char *pattern,
                                int encoding);
static void append_btree_pattern(PatternInfoArray *pia, const char *pattern,
                                 int encoding);
static void compile_database_list(PGconn *conn, SimplePtrList *databases,
                                  const char *initial_dbname);
static void compile_relation_list_one_db(PGconn *conn, SimplePtrList *relations,
                                         const DatabaseInfo *dat,
                                         uint64 *pagecount);
 
#define log_no_match(...) do { \
        if (opts.strict_names) \
            pg_log_error(__VA_ARGS__); \
        else \
            pg_log_warning(__VA_ARGS__); \
    } while(0)
 
#define FREE_AND_SET_NULL(x) do { \
    pg_free(x); \
    (x) = NULL; \
    } while (0)
 
int
main(int argc, char *argv[])
{
    PGconn     *conn = NULL;
    SimplePtrListCell *cell;
    SimplePtrList databases = {NULL, NULL};
    SimplePtrList relations = {NULL, NULL};
    bool        failed = false;
    const char *latest_datname;
    int         parallel_workers;
    ParallelSlotArray *sa;
    PQExpBufferData sql;
    uint64      reltotal = 0;
    uint64      pageschecked = 0;
    uint64      pagestotal = 0;
    uint64      relprogress = 0;
    int         pattern_id;
 
    static struct option long_options[] = {
        /* Connection options */
        {"host", required_argument, NULL, 'h'},
        {"port", required_argument, NULL, 'p'},
        {"username", required_argument, NULL, 'U'},
        {"no-password", no_argument, NULL, 'w'},
        {"password", no_argument, NULL, 'W'},
        {"maintenance-db", required_argument, NULL, 1},
 
        /* check options */
        {"all", no_argument, NULL, 'a'},
        {"database", required_argument, NULL, 'd'},
        {"exclude-database", required_argument, NULL, 'D'},
        {"echo", no_argument, NULL, 'e'},
        {"index", required_argument, NULL, 'i'},
        {"exclude-index", required_argument, NULL, 'I'},
        {"jobs", required_argument, NULL, 'j'},
        {"progress", no_argument, NULL, 'P'},
        {"relation", required_argument, NULL, 'r'},
        {"exclude-relation", required_argument, NULL, 'R'},
        {"schema", required_argument, NULL, 's'},
        {"exclude-schema", required_argument, NULL, 'S'},
        {"table", required_argument, NULL, 't'},
        {"exclude-table", required_argument, NULL, 'T'},
        {"verbose", no_argument, NULL, 'v'},
        {"no-dependent-indexes", no_argument, NULL, 2},
        {"no-dependent-toast", no_argument, NULL, 3},
        {"exclude-toast-pointers", no_argument, NULL, 4},
        {"on-error-stop", no_argument, NULL, 5},
        {"skip", required_argument, NULL, 6},
        {"startblock", required_argument, NULL, 7},
        {"endblock", required_argument, NULL, 8},
        {"rootdescend", no_argument, NULL, 9},
        {"no-strict-names", no_argument, NULL, 10},
        {"heapallindexed", no_argument, NULL, 11},
        {"parent-check", no_argument, NULL, 12},
        {"install-missing", optional_argument, NULL, 13},
 
        {NULL, 0, NULL, 0}
    };
 
    int         optindex;
    int         c;
 
    const char *db = NULL;
    const char *maintenance_db = NULL;
 
    const char *host = NULL;
    const char *port = NULL;
    const char *username = NULL;
    enum trivalue prompt_password = TRI_DEFAULT;
    int         encoding = pg_get_encoding_from_locale(NULL, false);
    ConnParams  cparams;
 
    pg_logging_init(argv[0]);
    progname = get_progname(argv[0]);
    set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_amcheck"));
 
    handle_help_version_opts(argc, argv, progname, help);
 
    /* process command-line options */
    while ((c = getopt_long(argc, argv, "ad:D:eh:Hi:I:j:p:Pr:R:s:S:t:T:U:vwW",
                            long_options, &optindex)) != -1)
    {
        char       *endptr;
        unsigned long optval;
 
        switch (c)
        {
            case 'a':
                opts.alldb = true;
                break;
            case 'd':
                opts.dbpattern = true;
                append_database_pattern(&opts.include, optarg, encoding);
                break;
            case 'D':
                opts.dbpattern = true;
                append_database_pattern(&opts.exclude, optarg, encoding);
                break;
            case 'e':
                opts.echo = true;
                break;
            case 'h':
                host = pg_strdup(optarg);
                break;
            case 'i':
                opts.allrel = false;
                append_btree_pattern(&opts.include, optarg, encoding);
                break;
            case 'I':
                opts.excludeidx = true;
                append_btree_pattern(&opts.exclude, optarg, encoding);
                break;
            case 'j':
                if (!option_parse_int(optarg, "-j/--jobs", 1, INT_MAX,
                                      &opts.jobs))
                    exit(1);
                break;
            case 'p':
                port = pg_strdup(optarg);
                break;
            case 'P':
                opts.show_progress = true;
                break;
            case 'r':
                opts.allrel = false;
                append_relation_pattern(&opts.include, optarg, encoding);
                break;
            case 'R':
                opts.excludeidx = true;
                opts.excludetbl = true;
                append_relation_pattern(&opts.exclude, optarg, encoding);
                break;
            case 's':
                opts.allrel = false;
                append_schema_pattern(&opts.include, optarg, encoding);
                break;
            case 'S':
                opts.excludensp = true;
                append_schema_pattern(&opts.exclude, optarg, encoding);
                break;
            case 't':
                opts.allrel = false;
                append_heap_pattern(&opts.include, optarg, encoding);
                break;
            case 'T':
                opts.excludetbl = true;
                append_heap_pattern(&opts.exclude, optarg, encoding);
                break;
            case 'U':
                username = pg_strdup(optarg);
                break;
            case 'v':
                opts.verbose = true;
                pg_logging_increase_verbosity();
                break;
            case 'w':
                prompt_password = TRI_NO;
                break;
            case 'W':
                prompt_password = TRI_YES;
                break;
            case 1:
                maintenance_db = pg_strdup(optarg);
                break;
            case 2:
                opts.no_btree_expansion = true;
                break;
            case 3:
                opts.no_toast_expansion = true;
                break;
            case 4:
                opts.reconcile_toast = false;
                break;
            case 5:
                opts.on_error_stop = true;
                break;
            case 6:
                if (pg_strcasecmp(optarg, "all-visible") == 0)
                    opts.skip = "all-visible";
                else if (pg_strcasecmp(optarg, "all-frozen") == 0)
                    opts.skip = "all-frozen";
                else if (pg_strcasecmp(optarg, "none") == 0)
                    opts.skip = "none";
                else
                    pg_fatal("invalid argument for option %s", "--skip");
                break;
            case 7:
                errno = 0;
                optval = strtoul(optarg, &endptr, 10);
                if (endptr == optarg || *endptr != '\0' || errno != 0)
                    pg_fatal("invalid start block");
                if (optval > MaxBlockNumber)
                    pg_fatal("start block out of bounds");
                opts.startblock = optval;
                break;
            case 8:
                errno = 0;
                optval = strtoul(optarg, &endptr, 10);
                if (endptr == optarg || *endptr != '\0' || errno != 0)
                    pg_fatal("invalid end block");
                if (optval > MaxBlockNumber)
                    pg_fatal("end block out of bounds");
                opts.endblock = optval;
                break;
            case 9:
                opts.rootdescend = true;
                opts.parent_check = true;
                break;
            case 10:
                opts.strict_names = false;
                break;
            case 11:
                opts.heapallindexed = true;
                break;
            case 12:
                opts.parent_check = true;
                break;
            case 13:
                opts.install_missing = true;
                if (optarg)
                    opts.install_schema = pg_strdup(optarg);
                break;
            default:
                /* getopt_long already emitted a complaint */
                pg_log_error_hint("Try \"%s --help\" for more information.", progname);
                exit(1);
        }
    }
 
    if (opts.endblock >= 0 && opts.endblock < opts.startblock)
        pg_fatal("end block precedes start block");
 
    /*
     * A single non-option arguments specifies a database name or connection
     * string.
     */
    if (optind < argc)
    {
        db = argv[optind];
        optind++;
    }
 
    if (optind < argc)
    {
        pg_log_error("too many command-line arguments (first is \"%s\")",
                     argv[optind]);
        pg_log_error_hint("Try \"%s --help\" for more information.", progname);
        exit(1);
    }
 
    /* fill cparams except for dbname, which is set below */
    cparams.pghost = host;
    cparams.pgport = port;
    cparams.pguser = username;
    cparams.prompt_password = prompt_password;
    cparams.dbname = NULL;
    cparams.override_dbname = NULL;
 
    setup_cancel_handler(NULL);
 
    /* choose the database for our initial connection */
    if (opts.alldb)
    {
        if (db != NULL)
            pg_fatal("cannot specify a database name with --all");
        cparams.dbname = maintenance_db;
    }
    else if (db != NULL)
    {
        if (opts.dbpattern)
            pg_fatal("cannot specify both a database name and database patterns");
        cparams.dbname = db;
    }
 
    if (opts.alldb || opts.dbpattern)
    {
        conn = connectMaintenanceDatabase(&cparams, progname, opts.echo);
        compile_database_list(conn, &databases, NULL);
    }
    else
    {
        if (cparams.dbname == NULL)
        {
            if (getenv("PGDATABASE"))
                cparams.dbname = getenv("PGDATABASE");
            else if (getenv("PGUSER"))
                cparams.dbname = getenv("PGUSER");
            else
                cparams.dbname = get_user_name_or_exit(progname);
        }
        conn = connectDatabase(&cparams, progname, opts.echo, false, true);
        compile_database_list(conn, &databases, PQdb(conn));
    }
 
    if (databases.head == NULL)
    {
        if (conn != NULL)
            disconnectDatabase(conn);
        pg_log_warning("no databases to check");
        exit(0);
    }
 
    /*
     * Compile a list of all relations spanning all databases to be checked.
     */
    for (cell = databases.head; cell; cell = cell->next)
    {
        PGresult   *result;
        int         ntups;
        const char *amcheck_schema = NULL;
        DatabaseInfo *dat = (DatabaseInfo *) cell->ptr;
 
        cparams.override_dbname = dat->datname;
        if (conn == NULL || strcmp(PQdb(conn), dat->datname) != 0)
        {
            if (conn != NULL)
                disconnectDatabase(conn);
            conn = connectDatabase(&cparams, progname, opts.echo, false, true);
        }
 
        /*
         * Optionally install amcheck if not already installed in this
         * database.
         */
        if (opts.install_missing)
        {
            char       *schema;
            char       *install_sql;
 
            /*
             * Must re-escape the schema name for each database, as the
             * escaping rules may change.
             */
            schema = PQescapeIdentifier(conn, opts.install_schema,
                                        strlen(opts.install_schema));
            install_sql = psprintf("CREATE EXTENSION IF NOT EXISTS amcheck WITH SCHEMA %s",
                                   schema);
 
            executeCommand(conn, install_sql, opts.echo);
            pfree(install_sql);
            pfree(schema);
        }
 
        /*
         * Verify that amcheck is installed for this next database.  User
         * error could result in a database not having amcheck that should
         * have it, but we also could be iterating over multiple databases
         * where not all of them have amcheck installed (for example,
         * 'template1').
         */
        result = executeQuery(conn, amcheck_sql, opts.echo);
        if (PQresultStatus(result) != PGRES_TUPLES_OK)
        {
            /* Querying the catalog failed. */
            pg_log_error("database \"%s\": %s",
                         PQdb(conn), PQerrorMessage(conn));
            pg_log_error_detail("Query was: %s", amcheck_sql);
            PQclear(result);
            disconnectDatabase(conn);
            exit(1);
        }
        ntups = PQntuples(result);
        if (ntups == 0)
        {
            /* Querying the catalog succeeded, but amcheck is missing. */
            pg_log_warning("skipping database \"%s\": amcheck is not installed",
                           PQdb(conn));
            disconnectDatabase(conn);
            conn = NULL;
            continue;
        }
        amcheck_schema = PQgetvalue(result, 0, 0);
        if (opts.verbose)
            pg_log_info("in database \"%s\": using amcheck version \"%s\" in schema \"%s\"",
                        PQdb(conn), PQgetvalue(result, 0, 1), amcheck_schema);
        dat->amcheck_schema = PQescapeIdentifier(conn, amcheck_schema,
                                                 strlen(amcheck_schema));
        PQclear(result);
 
        compile_relation_list_one_db(conn, &relations, dat, &pagestotal);
    }
 
    /*
     * Check that all inclusion patterns matched at least one schema or
     * relation that we can check.
     */
    for (pattern_id = 0; pattern_id < opts.include.len; pattern_id++)
    {
        PatternInfo *pat = &opts.include.data[pattern_id];
 
        if (!pat->matched && (pat->nsp_regex != NULL || pat->rel_regex != NULL))
        {
            failed = opts.strict_names;
 
            if (pat->heap_only)
                log_no_match("no heap tables to check matching \"%s\"",
                             pat->pattern);
            else if (pat->btree_only)
                log_no_match("no btree indexes to check matching \"%s\"",
                             pat->pattern);
            else if (pat->rel_regex == NULL)
                log_no_match("no relations to check in schemas matching \"%s\"",
                             pat->pattern);
            else
                log_no_match("no relations to check matching \"%s\"",
                             pat->pattern);
        }
    }
 
    if (failed)
    {
        if (conn != NULL)
            disconnectDatabase(conn);
        exit(1);
    }
 
    /*
     * Set parallel_workers to the lesser of opts.jobs and the number of
     * relations.
     */
    parallel_workers = 0;
    for (cell = relations.head; cell; cell = cell->next)
    {
        reltotal++;
        if (parallel_workers < opts.jobs)
            parallel_workers++;
    }
 
    if (reltotal == 0)
    {
        if (conn != NULL)
            disconnectDatabase(conn);
        pg_fatal("no relations to check");
    }
    progress_report(reltotal, relprogress, pagestotal, pageschecked,
                    NULL, true, false);
 
    /*
     * Main event loop.
     *
     * We use server-side parallelism to check up to parallel_workers
     * relations in parallel.  The list of relations was computed in database
     * order, which minimizes the number of connects and disconnects as we
     * process the list.
     */
    latest_datname = NULL;
    sa = ParallelSlotsSetup(parallel_workers, &cparams, progname, opts.echo,
                            NULL);
    if (conn != NULL)
    {
        ParallelSlotsAdoptConn(sa, conn);
        conn = NULL;
    }
 
    initPQExpBuffer(&sql);
    for (relprogress = 0, cell = relations.head; cell; cell = cell->next)
    {
        ParallelSlot *free_slot;
        RelationInfo *rel;
 
        rel = (RelationInfo *) cell->ptr;
 
        if (CancelRequested)
        {
            failed = true;
            break;
        }
 
        /*
         * The list of relations is in database sorted order.  If this next
         * relation is in a different database than the last one seen, we are
         * about to start checking this database.  Note that other slots may
         * still be working on relations from prior databases.
         */
        latest_datname = rel->datinfo->datname;
 
        progress_report(reltotal, relprogress, pagestotal, pageschecked,
                        latest_datname, false, false);
 
        relprogress++;
        pageschecked += rel->blocks_to_check;
 
        /*
         * Get a parallel slot for the next amcheck command, blocking if
         * necessary until one is available, or until a previously issued slot
         * command fails, indicating that we should abort checking the
         * remaining objects.
         */
        free_slot = ParallelSlotsGetIdle(sa, rel->datinfo->datname);
        if (!free_slot)
        {
            /*
             * Something failed.  We don't need to know what it was, because
             * the handler should already have emitted the necessary error
             * messages.
             */
            failed = true;
            break;
        }
 
        if (opts.verbose)
            PQsetErrorVerbosity(free_slot->connection, PQERRORS_VERBOSE);
 
        /*
         * Execute the appropriate amcheck command for this relation using our
         * slot's database connection.  We do not wait for the command to
         * complete, nor do we perform any error checking, as that is done by
         * the parallel slots and our handler callback functions.
         */
        if (rel->is_heap)
        {
            if (opts.verbose)
            {
                if (opts.show_progress && progress_since_last_stderr)
                    fprintf(stderr, "\n");
                pg_log_info("checking heap table \"%s.%s.%s\"",
                            rel->datinfo->datname, rel->nspname, rel->relname);
                progress_since_last_stderr = false;
            }
            prepare_heap_command(&sql, rel, free_slot->connection);
            rel->sql = pstrdup(sql.data);   /* pg_free'd after command */
            ParallelSlotSetHandler(free_slot, verify_heap_slot_handler, rel);
            run_command(free_slot, rel->sql);
        }
        else
        {
            if (opts.verbose)
            {
                if (opts.show_progress && progress_since_last_stderr)
                    fprintf(stderr, "\n");
 
                pg_log_info("checking btree index \"%s.%s.%s\"",
                            rel->datinfo->datname, rel->nspname, rel->relname);
                progress_since_last_stderr = false;
            }
            prepare_btree_command(&sql, rel, free_slot->connection);
            rel->sql = pstrdup(sql.data);   /* pg_free'd after command */
            ParallelSlotSetHandler(free_slot, verify_btree_slot_handler, rel);
            run_command(free_slot, rel->sql);
        }
    }
    termPQExpBuffer(&sql);
 
    if (!failed)
    {
 
        /*
         * Wait for all slots to complete, or for one to indicate that an
         * error occurred.  Like above, we rely on the handler emitting the
         * necessary error messages.
         */
        if (sa && !ParallelSlotsWaitCompletion(sa))
            failed = true;
 
        progress_report(reltotal, relprogress, pagestotal, pageschecked, NULL, true, true);
    }
 
    if (sa)
    {
        ParallelSlotsTerminate(sa);
        FREE_AND_SET_NULL(sa);
    }
 
    if (failed)
        exit(1);
 
    if (!all_checks_pass)
        exit(2);
}
 
/*
 * prepare_heap_command
 *
 * Creates a SQL command for running amcheck checking on the given heap
 * relation.  The command is phrased as a SQL query, with column order and
 * names matching the expectations of verify_heap_slot_handler, which will
 * receive and handle each row returned from the verify_heapam() function.
 *
 * The constructed SQL command will silently skip temporary tables, as checking
 * them would needlessly draw errors from the underlying amcheck function.
 *
 * sql: buffer into which the heap table checking command will be written
 * rel: relation information for the heap table to be checked
 * conn: the connection to be used, for string escaping purposes
 */
static void
prepare_heap_command(PQExpBuffer sql, RelationInfo *rel, PGconn *conn)
{
    resetPQExpBuffer(sql);
    appendPQExpBuffer(sql,
                      "SELECT v.blkno, v.offnum, v.attnum, v.msg "
                      "FROM pg_catalog.pg_class c, %s.verify_heapam("
                      "\nrelation := c.oid, on_error_stop := %s, check_toast := %s, skip := '%s'",
                      rel->datinfo->amcheck_schema,
                      opts.on_error_stop ? "true" : "false",
                      opts.reconcile_toast ? "true" : "false",
                      opts.skip);
 
    if (opts.startblock >= 0)
        appendPQExpBuffer(sql, ", startblock := " INT64_FORMAT, opts.startblock);
    if (opts.endblock >= 0)
        appendPQExpBuffer(sql, ", endblock := " INT64_FORMAT, opts.endblock);
 
    appendPQExpBuffer(sql,
                      "\n) v WHERE c.oid = %u "
                      "AND c.relpersistence != 't'",
                      rel->reloid);
}
 
/*
 * prepare_btree_command
 *
 * Creates a SQL command for running amcheck checking on the given btree index
 * relation.  The command does not select any columns, as btree checking
 * functions do not return any, but rather return corruption information by
 * raising errors, which verify_btree_slot_handler expects.
 *
 * The constructed SQL command will silently skip temporary indexes, and
 * indexes being reindexed concurrently, as checking them would needlessly draw
 * errors from the underlying amcheck functions.
 *
 * sql: buffer into which the heap table checking command will be written
 * rel: relation information for the index to be checked
 * conn: the connection to be used, for string escaping purposes
 */
static void
prepare_btree_command(PQExpBuffer sql, RelationInfo *rel, PGconn *conn)
{
    resetPQExpBuffer(sql);
 
    if (opts.parent_check)
        appendPQExpBuffer(sql,
                          "SELECT %s.bt_index_parent_check("
                          "index := c.oid, heapallindexed := %s, rootdescend := %s)"
                          "\nFROM pg_catalog.pg_class c, pg_catalog.pg_index i "
                          "WHERE c.oid = %u "
                          "AND c.oid = i.indexrelid "
                          "AND c.relpersistence != 't' "
                          "AND i.indisready AND i.indisvalid AND i.indislive",
                          rel->datinfo->amcheck_schema,
                          (opts.heapallindexed ? "true" : "false"),
                          (opts.rootdescend ? "true" : "false"),
                          rel->reloid);
    else
        appendPQExpBuffer(sql,
                          "SELECT %s.bt_index_check("
                          "index := c.oid, heapallindexed := %s)"
                          "\nFROM pg_catalog.pg_class c, pg_catalog.pg_index i "
                          "WHERE c.oid = %u "
                          "AND c.oid = i.indexrelid "
                          "AND c.relpersistence != 't' "
                          "AND i.indisready AND i.indisvalid AND i.indislive",
                          rel->datinfo->amcheck_schema,
                          (opts.heapallindexed ? "true" : "false"),
                          rel->reloid);
}
 
/*
 * run_command
 *
 * Sends a command to the server without waiting for the command to complete.
 * Logs an error if the command cannot be sent, but otherwise any errors are
 * expected to be handled by a ParallelSlotHandler.
 *
 * If reconnecting to the database is necessary, the cparams argument may be
 * modified.
 *
 * slot: slot with connection to the server we should use for the command
 * sql: query to send
 */
static void
run_command(ParallelSlot *slot, const char *sql)
{
    if (opts.echo)
        printf("%s\n", sql);
 
    if (PQsendQuery(slot->connection, sql) == 0)
    {
        pg_log_error("error sending command to database \"%s\": %s",
                     PQdb(slot->connection),
                     PQerrorMessage(slot->connection));
        pg_log_error_detail("Command was: %s", sql);
        exit(1);
    }
}
 
/*
 * should_processing_continue
 *
 * Checks a query result returned from a query (presumably issued on a slot's
 * connection) to determine if parallel slots should continue issuing further
 * commands.
 *
 * Note: Heap relation corruption is reported by verify_heapam() via the result
 * set, rather than an ERROR, but running verify_heapam() on a corrupted heap
 * table may still result in an error being returned from the server due to
 * missing relation files, bad checksums, etc.  The btree corruption checking
 * functions always use errors to communicate corruption messages.  We can't
 * just abort processing because we got a mere ERROR.
 *
 * res: result from an executed sql query
 */
static bool
should_processing_continue(PGresult *res)
{
    const char *severity;
 
    switch (PQresultStatus(res))
    {
            /* These are expected and ok */
        case PGRES_COMMAND_OK:
        case PGRES_TUPLES_OK:
        case PGRES_NONFATAL_ERROR:
            break;
 
            /* This is expected but requires closer scrutiny */
        case PGRES_FATAL_ERROR:
            severity = PQresultErrorField(res, PG_DIAG_SEVERITY_NONLOCALIZED);
            if (severity == NULL)
                return false;   /* libpq failure, probably lost connection */
            if (strcmp(severity, "FATAL") == 0)
                return false;
            if (strcmp(severity, "PANIC") == 0)
                return false;
            break;
 
            /* These are unexpected */
        case PGRES_BAD_RESPONSE:
        case PGRES_EMPTY_QUERY:
        case PGRES_COPY_OUT:
        case PGRES_COPY_IN:
        case PGRES_COPY_BOTH:
        case PGRES_SINGLE_TUPLE:
        case PGRES_PIPELINE_SYNC:
        case PGRES_PIPELINE_ABORTED:
            return false;
    }
    return true;
}
 
/*
 * Returns a copy of the argument string with all lines indented four spaces.
 *
 * The caller should pg_free the result when finished with it.
 */
static char *
indent_lines(const char *str)
{
    PQExpBufferData buf;
    const char *c;
    char       *result;
 
    initPQExpBuffer(&buf);
    appendPQExpBufferStr(&buf, "    ");
    for (c = str; *c; c++)
    {
        appendPQExpBufferChar(&buf, *c);
        if (c[0] == '\n' && c[1] != '\0')
            appendPQExpBufferStr(&buf, "    ");
    }
    result = pstrdup(buf.data);
    termPQExpBuffer(&buf);
 
    return result;
}
 
/*
 * verify_heap_slot_handler
 *
 * ParallelSlotHandler that receives results from a heap table checking command
 * created by prepare_heap_command and outputs the results for the user.
 *
 * res: result from an executed sql query
 * conn: connection on which the sql query was executed
 * context: the sql query being handled, as a cstring
 */
static bool
verify_heap_slot_handler(PGresult *res, PGconn *conn, void *context)
{
    RelationInfo *rel = (RelationInfo *) context;
 
    if (PQresultStatus(res) == PGRES_TUPLES_OK)
    {
        int         i;
        int         ntups = PQntuples(res);
 
        if (ntups > 0)
            all_checks_pass = false;
 
        for (i = 0; i < ntups; i++)
        {
            const char *msg;
 
            /* The message string should never be null, but check */
            if (PQgetisnull(res, i, 3))
                msg = "NO MESSAGE";
            else
                msg = PQgetvalue(res, i, 3);
 
            if (!PQgetisnull(res, i, 2))
                printf(_("heap table \"%s.%s.%s\", block %s, offset %s, attribute %s:\n"),
                       rel->datinfo->datname, rel->nspname, rel->relname,
                       PQgetvalue(res, i, 0),   /* blkno */
                       PQgetvalue(res, i, 1),   /* offnum */
                       PQgetvalue(res, i, 2));  /* attnum */
 
            else if (!PQgetisnull(res, i, 1))
                printf(_("heap table \"%s.%s.%s\", block %s, offset %s:\n"),
                       rel->datinfo->datname, rel->nspname, rel->relname,
                       PQgetvalue(res, i, 0),   /* blkno */
                       PQgetvalue(res, i, 1));  /* offnum */
 
            else if (!PQgetisnull(res, i, 0))
                printf(_("heap table \"%s.%s.%s\", block %s:\n"),
                       rel->datinfo->datname, rel->nspname, rel->relname,
                       PQgetvalue(res, i, 0));  /* blkno */
 
            else
                printf(_("heap table \"%s.%s.%s\":\n"),
                       rel->datinfo->datname, rel->nspname, rel->relname);
 
            printf("    %s\n", msg);
        }
    }
    else if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        char       *msg = indent_lines(PQerrorMessage(conn));
 
        all_checks_pass = false;
        printf(_("heap table \"%s.%s.%s\":\n"),
               rel->datinfo->datname, rel->nspname, rel->relname);
        printf("%s", msg);
        if (opts.verbose)
            printf(_("query was: %s\n"), rel->sql);
        FREE_AND_SET_NULL(msg);
    }
 
    FREE_AND_SET_NULL(rel->sql);
    FREE_AND_SET_NULL(rel->nspname);
    FREE_AND_SET_NULL(rel->relname);
 
    return should_processing_continue(res);
}
 
/*
 * verify_btree_slot_handler
 *
 * ParallelSlotHandler that receives results from a btree checking command
 * created by prepare_btree_command and outputs them for the user.  The results
 * from the btree checking command is assumed to be empty, but when the results
 * are an error code, the useful information about the corruption is expected
 * in the connection's error message.
 *
 * res: result from an executed sql query
 * conn: connection on which the sql query was executed
 * context: unused
 */
static bool
verify_btree_slot_handler(PGresult *res, PGconn *conn, void *context)
{
    RelationInfo *rel = (RelationInfo *) context;
 
    if (PQresultStatus(res) == PGRES_TUPLES_OK)
    {
        int         ntups = PQntuples(res);
 
        if (ntups > 1)
        {
            /*
             * We expect the btree checking functions to return one void row
             * each, or zero rows if the check was skipped due to the object
             * being in the wrong state to be checked, so we should output
             * some sort of warning if we get anything more, not because it
             * indicates corruption, but because it suggests a mismatch
             * between amcheck and pg_amcheck versions.
             *
             * In conjunction with --progress, anything written to stderr at
             * this time would present strangely to the user without an extra
             * newline, so we print one.  If we were multithreaded, we'd have
             * to avoid splitting this across multiple calls, but we're in an
             * event loop, so it doesn't matter.
             */
            if (opts.show_progress && progress_since_last_stderr)
                fprintf(stderr, "\n");
            pg_log_warning("btree index \"%s.%s.%s\": btree checking function returned unexpected number of rows: %d",
                           rel->datinfo->datname, rel->nspname, rel->relname, ntups);
            if (opts.verbose)
                pg_log_warning_detail("Query was: %s", rel->sql);
            pg_log_warning_hint("Are %s's and amcheck's versions compatible?",
                                progname);
            progress_since_last_stderr = false;
        }
    }
    else
    {
        char       *msg = indent_lines(PQerrorMessage(conn));
 
        all_checks_pass = false;
        printf(_("btree index \"%s.%s.%s\":\n"),
               rel->datinfo->datname, rel->nspname, rel->relname);
        printf("%s", msg);
        if (opts.verbose)
            printf(_("query was: %s\n"), rel->sql);
        FREE_AND_SET_NULL(msg);
    }
 
    FREE_AND_SET_NULL(rel->sql);
    FREE_AND_SET_NULL(rel->nspname);
    FREE_AND_SET_NULL(rel->relname);
 
    return should_processing_continue(res);
}
 
/*
 * help
 *
 * Prints help page for the program
 *
 * progname: the name of the executed program, such as "pg_amcheck"
 */
static void
help(const char *progname)
{
    printf(_("%s checks objects in a PostgreSQL database for corruption.\n\n"), progname);
    printf(_("Usage:\n"));
    printf(_("  %s [OPTION]... [DBNAME]\n"), progname);
    printf(_("\nTarget options:\n"));
    printf(_("  -a, --all                       check all databases\n"));
    printf(_("  -d, --database=PATTERN          check matching database(s)\n"));
    printf(_("  -D, --exclude-database=PATTERN  do NOT check matching database(s)\n"));
    printf(_("  -i, --index=PATTERN             check matching index(es)\n"));
    printf(_("  -I, --exclude-index=PATTERN     do NOT check matching index(es)\n"));
    printf(_("  -r, --relation=PATTERN          check matching relation(s)\n"));
    printf(_("  -R, --exclude-relation=PATTERN  do NOT check matching relation(s)\n"));
    printf(_("  -s, --schema=PATTERN            check matching schema(s)\n"));
    printf(_("  -S, --exclude-schema=PATTERN    do NOT check matching schema(s)\n"));
    printf(_("  -t, --table=PATTERN             check matching table(s)\n"));
    printf(_("  -T, --exclude-table=PATTERN     do NOT check matching table(s)\n"));
    printf(_("      --no-dependent-indexes      do NOT expand list of relations to include indexes\n"));
    printf(_("      --no-dependent-toast        do NOT expand list of relations to include TOAST tables\n"));
    printf(_("      --no-strict-names           do NOT require patterns to match objects\n"));
    printf(_("\nTable checking options:\n"));
    printf(_("      --exclude-toast-pointers    do NOT follow relation TOAST pointers\n"));
    printf(_("      --on-error-stop             stop checking at end of first corrupt page\n"));
    printf(_("      --skip=OPTION               do NOT check \"all-frozen\" or \"all-visible\" blocks\n"));
    printf(_("      --startblock=BLOCK          begin checking table(s) at the given block number\n"));
    printf(_("      --endblock=BLOCK            check table(s) only up to the given block number\n"));
    printf(_("\nB-tree index checking options:\n"));
    printf(_("      --heapallindexed            check that all heap tuples are found within indexes\n"));
    printf(_("      --parent-check              check index parent/child relationships\n"));
    printf(_("      --rootdescend               search from root page to refind tuples\n"));
    printf(_("\nConnection options:\n"));
    printf(_("  -h, --host=HOSTNAME             database server host or socket directory\n"));
    printf(_("  -p, --port=PORT                 database server port\n"));
    printf(_("  -U, --username=USERNAME         user name to connect as\n"));
    printf(_("  -w, --no-password               never prompt for password\n"));
    printf(_("  -W, --password                  force password prompt\n"));
    printf(_("      --maintenance-db=DBNAME     alternate maintenance database\n"));
    printf(_("\nOther options:\n"));
    printf(_("  -e, --echo                      show the commands being sent to the server\n"));
    printf(_("  -j, --jobs=NUM                  use this many concurrent connections to the server\n"));
    printf(_("  -P, --progress                  show progress information\n"));
    printf(_("  -v, --verbose                   write a lot of output\n"));
    printf(_("  -V, --version                   output version information, then exit\n"));
    printf(_("      --install-missing           install missing extensions\n"));
    printf(_("  -?, --help                      show this help, then exit\n"));
 
    printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
}
 
/*
 * Print a progress report based on the global variables.
 *
 * Progress report is written at maximum once per second, unless the force
 * parameter is set to true.
 *
 * If finished is set to true, this is the last progress report. The cursor
 * is moved to the next line.
 */
static void
progress_report(uint64 relations_total, uint64 relations_checked,
                uint64 relpages_total, uint64 relpages_checked,
                const char *datname, bool force, bool finished)
{
    int         percent_rel = 0;
    int         percent_pages = 0;
    char        checked_rel[32];
    char        total_rel[32];
    char        checked_pages[32];
    char        total_pages[32];
    pg_time_t   now;
 
    if (!opts.show_progress)
        return;
 
    now = time(NULL);
    if (now == last_progress_report && !force && !finished)
        return;                 /* Max once per second */
 
    last_progress_report = now;
    if (relations_total)
        percent_rel = (int) (relations_checked * 100 / relations_total);
    if (relpages_total)
        percent_pages = (int) (relpages_checked * 100 / relpages_total);
 
    snprintf(checked_rel, sizeof(checked_rel), UINT64_FORMAT, relations_checked);
    snprintf(total_rel, sizeof(total_rel), UINT64_FORMAT, relations_total);
    snprintf(checked_pages, sizeof(checked_pages), UINT64_FORMAT, relpages_checked);
    snprintf(total_pages, sizeof(total_pages), UINT64_FORMAT, relpages_total);
 
#define VERBOSE_DATNAME_LENGTH 35
    if (opts.verbose)
    {
        if (!datname)
 
            /*
             * No datname given, so clear the status line (used for first and
             * last call)
             */
            fprintf(stderr,
                    _("%*s/%s relations (%d%%), %*s/%s pages (%d%%) %*s"),
                    (int) strlen(total_rel),
                    checked_rel, total_rel, percent_rel,
                    (int) strlen(total_pages),
                    checked_pages, total_pages, percent_pages,
                    VERBOSE_DATNAME_LENGTH + 2, "");
        else
        {
            bool        truncate = (strlen(datname) > VERBOSE_DATNAME_LENGTH);
 
            fprintf(stderr,
                    _("%*s/%s relations (%d%%), %*s/%s pages (%d%%) (%s%-*.*s)"),
                    (int) strlen(total_rel),
                    checked_rel, total_rel, percent_rel,
                    (int) strlen(total_pages),
                    checked_pages, total_pages, percent_pages,
            /* Prefix with "..." if we do leading truncation */
                    truncate ? "..." : "",
                    truncate ? VERBOSE_DATNAME_LENGTH - 3 : VERBOSE_DATNAME_LENGTH,
                    truncate ? VERBOSE_DATNAME_LENGTH - 3 : VERBOSE_DATNAME_LENGTH,
            /* Truncate datname at beginning if it's too long */
                    truncate ? datname + strlen(datname) - VERBOSE_DATNAME_LENGTH + 3 : datname);
        }
    }
    else
        fprintf(stderr,
                _("%*s/%s relations (%d%%), %*s/%s pages (%d%%)"),
                (int) strlen(total_rel),
                checked_rel, total_rel, percent_rel,
                (int) strlen(total_pages),
                checked_pages, total_pages, percent_pages);
 
    /*
     * Stay on the same line if reporting to a terminal and we're not done
     * yet.
     */
    if (!finished && isatty(fileno(stderr)))
    {
        fputc('\r', stderr);
        progress_since_last_stderr = true;
    }
    else
        fputc('\n', stderr);
}
 
/*
 * Extend the pattern info array to hold one additional initialized pattern
 * info entry.
 *
 * Returns a pointer to the new entry.
 */
static PatternInfo *
extend_pattern_info_array(PatternInfoArray *pia)
{
    PatternInfo *result;
 
    pia->len++;
    pia->data = (PatternInfo *) pg_realloc(pia->data, pia->len * sizeof(PatternInfo));
    result = &pia->data[pia->len - 1];
    memset(result, 0, sizeof(*result));
 
    return result;
}
 
/*
 * append_database_pattern
 *
 * Adds the given pattern interpreted as a database name pattern.
 *
 * pia: the pattern info array to be appended
 * pattern: the database name pattern
 * encoding: client encoding for parsing the pattern
 */
static void
append_database_pattern(PatternInfoArray *pia, const char *pattern, int encoding)
{
    PQExpBufferData buf;
    int         dotcnt;
    PatternInfo *info = extend_pattern_info_array(pia);
 
    initPQExpBuffer(&buf);
    patternToSQLRegex(encoding, NULL, NULL, &buf, pattern, false, false,
                      &dotcnt);
    if (dotcnt > 0)
    {
        pg_log_error("improper qualified name (too many dotted names): %s", pattern);
        exit(2);
    }
    info->pattern = pattern;
    info->db_regex = pstrdup(buf.data);
 
    termPQExpBuffer(&buf);
}
 
/*
 * append_schema_pattern
 *
 * Adds the given pattern interpreted as a schema name pattern.
 *
 * pia: the pattern info array to be appended
 * pattern: the schema name pattern
 * encoding: client encoding for parsing the pattern
 */
static void
append_schema_pattern(PatternInfoArray *pia, const char *pattern, int encoding)
{
    PQExpBufferData dbbuf;
    PQExpBufferData nspbuf;
    int         dotcnt;
    PatternInfo *info = extend_pattern_info_array(pia);
 
    initPQExpBuffer(&dbbuf);
    initPQExpBuffer(&nspbuf);
 
    patternToSQLRegex(encoding, NULL, &dbbuf, &nspbuf, pattern, false, false,
                      &dotcnt);
    if (dotcnt > 1)
    {
        pg_log_error("improper qualified name (too many dotted names): %s", pattern);
        exit(2);
    }
    info->pattern = pattern;
    if (dbbuf.data[0])
    {
        opts.dbpattern = true;
        info->db_regex = pstrdup(dbbuf.data);
    }
    if (nspbuf.data[0])
        info->nsp_regex = pstrdup(nspbuf.data);
 
    termPQExpBuffer(&dbbuf);
    termPQExpBuffer(&nspbuf);
}
 
/*
 * append_relation_pattern_helper
 *
 * Adds to a list the given pattern interpreted as a relation pattern.
 *
 * pia: the pattern info array to be appended
 * pattern: the relation name pattern
 * encoding: client encoding for parsing the pattern
 * heap_only: whether the pattern should only be matched against heap tables
 * btree_only: whether the pattern should only be matched against btree indexes
 */
static void
append_relation_pattern_helper(PatternInfoArray *pia, const char *pattern,
                               int encoding, bool heap_only, bool btree_only)
{
    PQExpBufferData dbbuf;
    PQExpBufferData nspbuf;
    PQExpBufferData relbuf;
    int         dotcnt;
    PatternInfo *info = extend_pattern_info_array(pia);
 
    initPQExpBuffer(&dbbuf);
    initPQExpBuffer(&nspbuf);
    initPQExpBuffer(&relbuf);
 
    patternToSQLRegex(encoding, &dbbuf, &nspbuf, &relbuf, pattern, false,
                      false, &dotcnt);
    if (dotcnt > 2)
    {
        pg_log_error("improper relation name (too many dotted names): %s", pattern);
        exit(2);
    }
    info->pattern = pattern;
    if (dbbuf.data[0])
    {
        opts.dbpattern = true;
        info->db_regex = pstrdup(dbbuf.data);
    }
    if (nspbuf.data[0])
        info->nsp_regex = pstrdup(nspbuf.data);
    if (relbuf.data[0])
        info->rel_regex = pstrdup(relbuf.data);
 
    termPQExpBuffer(&dbbuf);
    termPQExpBuffer(&nspbuf);
    termPQExpBuffer(&relbuf);
 
    info->heap_only = heap_only;
    info->btree_only = btree_only;
}
 
/*
 * append_relation_pattern
 *
 * Adds the given pattern interpreted as a relation pattern, to be matched
 * against both heap tables and btree indexes.
 *
 * pia: the pattern info array to be appended
 * pattern: the relation name pattern
 * encoding: client encoding for parsing the pattern
 */
static void
append_relation_pattern(PatternInfoArray *pia, const char *pattern, int encoding)
{
    append_relation_pattern_helper(pia, pattern, encoding, false, false);
}
 
/*
 * append_heap_pattern
 *
 * Adds the given pattern interpreted as a relation pattern, to be matched only
 * against heap tables.
 *
 * pia: the pattern info array to be appended
 * pattern: the relation name pattern
 * encoding: client encoding for parsing the pattern
 */
static void
append_heap_pattern(PatternInfoArray *pia, const char *pattern, int encoding)
{
    append_relation_pattern_helper(pia, pattern, encoding, true, false);
}
 
/*
 * append_btree_pattern
 *
 * Adds the given pattern interpreted as a relation pattern, to be matched only
 * against btree indexes.
 *
 * pia: the pattern info array to be appended
 * pattern: the relation name pattern
 * encoding: client encoding for parsing the pattern
 */
static void
append_btree_pattern(PatternInfoArray *pia, const char *pattern, int encoding)
{
    append_relation_pattern_helper(pia, pattern, encoding, false, true);
}
 
/*
 * append_db_pattern_cte
 *
 * Appends to the buffer the body of a Common Table Expression (CTE) containing
 * the database portions filtered from the list of patterns expressed as two
 * columns:
 *
 *     pattern_id: the index of this pattern in pia->data[]
 *     rgx: the database regular expression parsed from the pattern
 *
 * Patterns without a database portion are skipped.  Patterns with more than
 * just a database portion are optionally skipped, depending on argument
 * 'inclusive'.
 *
 * buf: the buffer to be appended
 * pia: the array of patterns to be inserted into the CTE
 * conn: the database connection
 * inclusive: whether to include patterns with schema and/or relation parts
 *
 * Returns whether any database patterns were appended.
 */
static bool
append_db_pattern_cte(PQExpBuffer buf, const PatternInfoArray *pia,
                      PGconn *conn, bool inclusive)
{
    int         pattern_id;
    const char *comma;
    bool        have_values;
 
    comma = "";
    have_values = false;
    for (pattern_id = 0; pattern_id < pia->len; pattern_id++)
    {
        PatternInfo *info = &pia->data[pattern_id];
 
        if (info->db_regex != NULL &&
            (inclusive || (info->nsp_regex == NULL && info->rel_regex == NULL)))
        {
            if (!have_values)
                appendPQExpBufferStr(buf, "\nVALUES");
            have_values = true;
            appendPQExpBuffer(buf, "%s\n(%d, ", comma, pattern_id);
            appendStringLiteralConn(buf, info->db_regex, conn);
            appendPQExpBufferChar(buf, ')');
            comma = ",";
        }
    }
 
    if (!have_values)
        appendPQExpBufferStr(buf, "\nSELECT NULL, NULL, NULL WHERE false");
 
    return have_values;
}
 
/*
 * compile_database_list
 *
 * If any database patterns exist, or if --all was given, compiles a distinct
 * list of databases to check using a SQL query based on the patterns plus the
 * literal initial database name, if given.  If no database patterns exist and
 * --all was not given, the query is not necessary, and only the initial
 * database name (if any) is added to the list.
 *
 * conn: connection to the initial database
 * databases: the list onto which databases should be appended
 * initial_dbname: an optional extra database name to include in the list
 */
static void
compile_database_list(PGconn *conn, SimplePtrList *databases,
                      const char *initial_dbname)
{
    PGresult   *res;
    PQExpBufferData sql;
    int         ntups;
    int         i;
    bool        fatal;
 
    if (initial_dbname)
    {
        DatabaseInfo *dat = (DatabaseInfo *) pg_malloc0(sizeof(DatabaseInfo));
 
        /* This database is included.  Add to list */
        if (opts.verbose)
            pg_log_info("including database \"%s\"", initial_dbname);
 
        dat->datname = pstrdup(initial_dbname);
        simple_ptr_list_append(databases, dat);
    }
 
    initPQExpBuffer(&sql);
 
    /* Append the include patterns CTE. */
    appendPQExpBufferStr(&sql, "WITH include_raw (pattern_id, rgx) AS (");
    if (!append_db_pattern_cte(&sql, &opts.include, conn, true) &&
        !opts.alldb)
    {
        /*
         * None of the inclusion patterns (if any) contain database portions,
         * so there is no need to query the database to resolve database
         * patterns.
         *
         * Since we're also not operating under --all, we don't need to query
         * the exhaustive list of connectable databases, either.
         */
        termPQExpBuffer(&sql);
        return;
    }
 
    /* Append the exclude patterns CTE. */
    appendPQExpBufferStr(&sql, "),\nexclude_raw (pattern_id, rgx) AS (");
    append_db_pattern_cte(&sql, &opts.exclude, conn, false);
    appendPQExpBufferStr(&sql, "),");
 
    /*
     * Append the database CTE, which includes whether each database is
     * connectable and also joins against exclude_raw to determine whether
     * each database is excluded.
     */
    appendPQExpBufferStr(&sql,
                         "\ndatabase (datname) AS ("
                         "\nSELECT d.datname "
                         "FROM pg_catalog.pg_database d "
                         "LEFT OUTER JOIN exclude_raw e "
                         "ON d.datname ~ e.rgx "
                         "\nWHERE d.datallowconn AND datconnlimit != -2 "
                         "AND e.pattern_id IS NULL"
                         "),"
 
    /*
     * Append the include_pat CTE, which joins the include_raw CTE against the
     * databases CTE to determine if all the inclusion patterns had matches,
     * and whether each matched pattern had the misfortune of only matching
     * excluded or unconnectable databases.
     */
                         "\ninclude_pat (pattern_id, checkable) AS ("
                         "\nSELECT i.pattern_id, "
                         "COUNT(*) FILTER ("
                         "WHERE d IS NOT NULL"
                         ") AS checkable"
                         "\nFROM include_raw i "
                         "LEFT OUTER JOIN database d "
                         "ON d.datname ~ i.rgx"
                         "\nGROUP BY i.pattern_id"
                         "),"
 
    /*
     * Append the filtered_databases CTE, which selects from the database CTE
     * optionally joined against the include_raw CTE to only select databases
     * that match an inclusion pattern.  This appears to duplicate what the
     * include_pat CTE already did above, but here we want only databases, and
     * there we wanted patterns.
     */
                         "\nfiltered_databases (datname) AS ("
                         "\nSELECT DISTINCT d.datname "
                         "FROM database d");
    if (!opts.alldb)
        appendPQExpBufferStr(&sql,
                             " INNER JOIN include_raw i "
                             "ON d.datname ~ i.rgx");
    appendPQExpBufferStr(&sql,
                         ")"
 
    /*
     * Select the checkable databases and the unmatched inclusion patterns.
     */
                         "\nSELECT pattern_id, datname FROM ("
                         "\nSELECT pattern_id, NULL::TEXT AS datname "
                         "FROM include_pat "
                         "WHERE checkable = 0 "
                         "UNION ALL"
                         "\nSELECT NULL, datname "
                         "FROM filtered_databases"
                         ") AS combined_records"
                         "\nORDER BY pattern_id NULLS LAST, datname");
 
    res = executeQuery(conn, sql.data, opts.echo);
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        pg_log_error("query failed: %s", PQerrorMessage(conn));
        pg_log_error_detail("Query was: %s", sql.data);
        disconnectDatabase(conn);
        exit(1);
    }
    termPQExpBuffer(&sql);
 
    ntups = PQntuples(res);
    for (fatal = false, i = 0; i < ntups; i++)
    {
        int         pattern_id = -1;
        const char *datname = NULL;
 
        if (!PQgetisnull(res, i, 0))
            pattern_id = atoi(PQgetvalue(res, i, 0));
        if (!PQgetisnull(res, i, 1))
            datname = PQgetvalue(res, i, 1);
 
        if (pattern_id >= 0)
        {
            /*
             * Current record pertains to an inclusion pattern that matched no
             * checkable databases.
             */
            fatal = opts.strict_names;
            if (pattern_id >= opts.include.len)
                pg_fatal("internal error: received unexpected database pattern_id %d",
                         pattern_id);
            log_no_match("no connectable databases to check matching \"%s\"",
                         opts.include.data[pattern_id].pattern);
        }
        else
        {
            DatabaseInfo *dat;
 
            /* Current record pertains to a database */
            Assert(datname != NULL);
 
            /* Avoid entering a duplicate entry matching the initial_dbname */
            if (initial_dbname != NULL && strcmp(initial_dbname, datname) == 0)
                continue;
 
            /* This database is included.  Add to list */
            if (opts.verbose)
                pg_log_info("including database \"%s\"", datname);
 
            dat = (DatabaseInfo *) pg_malloc0(sizeof(DatabaseInfo));
            dat->datname = pstrdup(datname);
            simple_ptr_list_append(databases, dat);
        }
    }
    PQclear(res);
 
    if (fatal)
    {
        if (conn != NULL)
            disconnectDatabase(conn);
        exit(1);
    }
}
 
/*
 * append_rel_pattern_raw_cte
 *
 * Appends to the buffer the body of a Common Table Expression (CTE) containing
 * the given patterns as six columns:
 *
 *     pattern_id: the index of this pattern in pia->data[]
 *     db_regex: the database regexp parsed from the pattern, or NULL if the
 *               pattern had no database part
 *     nsp_regex: the namespace regexp parsed from the pattern, or NULL if the
 *                pattern had no namespace part
 *     rel_regex: the relname regexp parsed from the pattern, or NULL if the
 *                pattern had no relname part
 *     heap_only: true if the pattern applies only to heap tables (not indexes)
 *     btree_only: true if the pattern applies only to btree indexes (not tables)
 *
 * buf: the buffer to be appended
 * patterns: the array of patterns to be inserted into the CTE
 * conn: the database connection
 */
static void
append_rel_pattern_raw_cte(PQExpBuffer buf, const PatternInfoArray *pia,
                           PGconn *conn)
{
    int         pattern_id;
    const char *comma;
    bool        have_values;
 
    comma = "";
    have_values = false;
    for (pattern_id = 0; pattern_id < pia->len; pattern_id++)
    {
        PatternInfo *info = &pia->data[pattern_id];
 
        if (!have_values)
            appendPQExpBufferStr(buf, "\nVALUES");
        have_values = true;
        appendPQExpBuffer(buf, "%s\n(%d::INTEGER, ", comma, pattern_id);
        if (info->db_regex == NULL)
            appendPQExpBufferStr(buf, "NULL");
        else
            appendStringLiteralConn(buf, info->db_regex, conn);
        appendPQExpBufferStr(buf, "::TEXT, ");
        if (info->nsp_regex == NULL)
            appendPQExpBufferStr(buf, "NULL");
        else
            appendStringLiteralConn(buf, info->nsp_regex, conn);
        appendPQExpBufferStr(buf, "::TEXT, ");
        if (info->rel_regex == NULL)
            appendPQExpBufferStr(buf, "NULL");
        else
            appendStringLiteralConn(buf, info->rel_regex, conn);
        if (info->heap_only)
            appendPQExpBufferStr(buf, "::TEXT, true::BOOLEAN");
        else
            appendPQExpBufferStr(buf, "::TEXT, false::BOOLEAN");
        if (info->btree_only)
            appendPQExpBufferStr(buf, ", true::BOOLEAN");
        else
            appendPQExpBufferStr(buf, ", false::BOOLEAN");
        appendPQExpBufferChar(buf, ')');
        comma = ",";
    }
 
    if (!have_values)
        appendPQExpBufferStr(buf,
                             "\nSELECT NULL::INTEGER, NULL::TEXT, NULL::TEXT, "
                             "NULL::TEXT, NULL::BOOLEAN, NULL::BOOLEAN "
                             "WHERE false");
}
 
/*
 * append_rel_pattern_filtered_cte
 *
 * Appends to the buffer a Common Table Expression (CTE) which selects
 * all patterns from the named raw CTE, filtered by database.  All patterns
 * which have no database portion or whose database portion matches our
 * connection's database name are selected, with other patterns excluded.
 *
 * The basic idea here is that if we're connected to database "foo" and we have
 * patterns "foo.bar.baz", "alpha.beta" and "one.two.three", we only want to
 * use the first two while processing relations in this database, as the third
 * one is not relevant.
 *
 * buf: the buffer to be appended
 * raw: the name of the CTE to select from
 * filtered: the name of the CTE to create
 * conn: the database connection
 */
static void
append_rel_pattern_filtered_cte(PQExpBuffer buf, const char *raw,
                                const char *filtered, PGconn *conn)
{
    appendPQExpBuffer(buf,
                      "\n%s (pattern_id, nsp_regex, rel_regex, heap_only, btree_only) AS ("
                      "\nSELECT pattern_id, nsp_regex, rel_regex, heap_only, btree_only "
                      "FROM %s r"
                      "\nWHERE (r.db_regex IS NULL "
                      "OR ",
                      filtered, raw);
    appendStringLiteralConn(buf, PQdb(conn), conn);
    appendPQExpBufferStr(buf, " ~ r.db_regex)");
    appendPQExpBufferStr(buf,
                         " AND (r.nsp_regex IS NOT NULL"
                         " OR r.rel_regex IS NOT NULL)"
                         "),");
}
 
/*
 * compile_relation_list_one_db
 *
 * Compiles a list of relations to check within the currently connected
 * database based on the user supplied options, sorted by descending size,
 * and appends them to the given list of relations.
 *
 * The cells of the constructed list contain all information about the relation
 * necessary to connect to the database and check the object, including which
 * database to connect to, where contrib/amcheck is installed, and the Oid and
 * type of object (heap table vs. btree index).  Rather than duplicating the
 * database details per relation, the relation structs use references to the
 * same database object, provided by the caller.
 *
 * conn: connection to this next database, which should be the same as in 'dat'
 * relations: list onto which the relations information should be appended
 * dat: the database info struct for use by each relation
 * pagecount: gets incremented by the number of blocks to check in all
 * relations added
 */
static void
compile_relation_list_one_db(PGconn *conn, SimplePtrList *relations,
                             const DatabaseInfo *dat,
                             uint64 *pagecount)
{
    PGresult   *res;
    PQExpBufferData sql;
    int         ntups;
    int         i;
 
    initPQExpBuffer(&sql);
    appendPQExpBufferStr(&sql, "WITH");
 
    /* Append CTEs for the relation inclusion patterns, if any */
    if (!opts.allrel)
    {
        appendPQExpBufferStr(&sql,
                             " include_raw (pattern_id, db_regex, nsp_regex, rel_regex, heap_only, btree_only) AS (");
        append_rel_pattern_raw_cte(&sql, &opts.include, conn);
        appendPQExpBufferStr(&sql, "\n),");
        append_rel_pattern_filtered_cte(&sql, "include_raw", "include_pat", conn);
    }
 
    /* Append CTEs for the relation exclusion patterns, if any */
    if (opts.excludetbl || opts.excludeidx || opts.excludensp)
    {
        appendPQExpBufferStr(&sql,
                             " exclude_raw (pattern_id, db_regex, nsp_regex, rel_regex, heap_only, btree_only) AS (");
        append_rel_pattern_raw_cte(&sql, &opts.exclude, conn);
        appendPQExpBufferStr(&sql, "\n),");
        append_rel_pattern_filtered_cte(&sql, "exclude_raw", "exclude_pat", conn);
    }
 
    /* Append the relation CTE. */
    appendPQExpBufferStr(&sql,
                         " relation (pattern_id, oid, nspname, relname, reltoastrelid, relpages, is_heap, is_btree) AS ("
                         "\nSELECT DISTINCT ON (c.oid");
    if (!opts.allrel)
        appendPQExpBufferStr(&sql, ", ip.pattern_id) ip.pattern_id,");
    else
        appendPQExpBufferStr(&sql, ") NULL::INTEGER AS pattern_id,");
    appendPQExpBuffer(&sql,
                      "\nc.oid, n.nspname, c.relname, c.reltoastrelid, c.relpages, "
                      "c.relam = %u AS is_heap, "
                      "c.relam = %u AS is_btree"
                      "\nFROM pg_catalog.pg_class c "
                      "INNER JOIN pg_catalog.pg_namespace n "
                      "ON c.relnamespace = n.oid",
                      HEAP_TABLE_AM_OID, BTREE_AM_OID);
    if (!opts.allrel)
        appendPQExpBuffer(&sql,
                          "\nINNER JOIN include_pat ip"
                          "\nON (n.nspname ~ ip.nsp_regex OR ip.nsp_regex IS NULL)"
                          "\nAND (c.relname ~ ip.rel_regex OR ip.rel_regex IS NULL)"
                          "\nAND (c.relam = %u OR NOT ip.heap_only)"
                          "\nAND (c.relam = %u OR NOT ip.btree_only)",
                          HEAP_TABLE_AM_OID, BTREE_AM_OID);
    if (opts.excludetbl || opts.excludeidx || opts.excludensp)
        appendPQExpBuffer(&sql,
                          "\nLEFT OUTER JOIN exclude_pat ep"
                          "\nON (n.nspname ~ ep.nsp_regex OR ep.nsp_regex IS NULL)"
                          "\nAND (c.relname ~ ep.rel_regex OR ep.rel_regex IS NULL)"
                          "\nAND (c.relam = %u OR NOT ep.heap_only OR ep.rel_regex IS NULL)"
                          "\nAND (c.relam = %u OR NOT ep.btree_only OR ep.rel_regex IS NULL)",
                          HEAP_TABLE_AM_OID, BTREE_AM_OID);
 
    /*
     * Exclude temporary tables and indexes, which must necessarily belong to
     * other sessions.  (We don't create any ourselves.)  We must ultimately
     * exclude indexes marked invalid or not ready, but we delay that decision
     * until firing off the amcheck command, as the state of an index may
     * change by then.
     */
    appendPQExpBufferStr(&sql, "\nWHERE c.relpersistence != 't'");
    if (opts.excludetbl || opts.excludeidx || opts.excludensp)
        appendPQExpBufferStr(&sql, "\nAND ep.pattern_id IS NULL");
 
    /*
     * We need to be careful not to break the --no-dependent-toast and
     * --no-dependent-indexes options.  By default, the btree indexes, toast
     * tables, and toast table btree indexes associated with primary heap
     * tables are included, using their own CTEs below.  We implement the
     * --exclude-* options by not creating those CTEs, but that's no use if
     * we've already selected the toast and indexes here.  On the other hand,
     * we want inclusion patterns that match indexes or toast tables to be
     * honored.  So, if inclusion patterns were given, we want to select all
     * tables, toast tables, or indexes that match the patterns.  But if no
     * inclusion patterns were given, and we're simply matching all relations,
     * then we only want to match the primary tables here.
     */
    if (opts.allrel)
        appendPQExpBuffer(&sql,
                          " AND c.relam = %u "
                          "AND c.relkind IN ('r', 'S', 'm', 't') "
                          "AND c.relnamespace != %u",
                          HEAP_TABLE_AM_OID, PG_TOAST_NAMESPACE);
    else
        appendPQExpBuffer(&sql,
                          " AND c.relam IN (%u, %u)"
                          "AND c.relkind IN ('r', 'S', 'm', 't', 'i') "
                          "AND ((c.relam = %u AND c.relkind IN ('r', 'S', 'm', 't')) OR "
                          "(c.relam = %u AND c.relkind = 'i'))",
                          HEAP_TABLE_AM_OID, BTREE_AM_OID,
                          HEAP_TABLE_AM_OID, BTREE_AM_OID);
 
    appendPQExpBufferStr(&sql,
                         "\nORDER BY c.oid)");
 
    if (!opts.no_toast_expansion)
    {
        /*
         * Include a CTE for toast tables associated with primary heap tables
         * selected above, filtering by exclusion patterns (if any) that match
         * toast table names.
         */
        appendPQExpBufferStr(&sql,
                             ", toast (oid, nspname, relname, relpages) AS ("
                             "\nSELECT t.oid, 'pg_toast', t.relname, t.relpages"
                             "\nFROM pg_catalog.pg_class t "
                             "INNER JOIN relation r "
                             "ON r.reltoastrelid = t.oid");
        if (opts.excludetbl || opts.excludensp)
            appendPQExpBufferStr(&sql,
                                 "\nLEFT OUTER JOIN exclude_pat ep"
                                 "\nON ('pg_toast' ~ ep.nsp_regex OR ep.nsp_regex IS NULL)"
                                 "\nAND (t.relname ~ ep.rel_regex OR ep.rel_regex IS NULL)"
                                 "\nAND ep.heap_only"
                                 "\nWHERE ep.pattern_id IS NULL"
                                 "\nAND t.relpersistence != 't'");
        appendPQExpBufferStr(&sql,
                             "\n)");
    }
    if (!opts.no_btree_expansion)
    {
        /*
         * Include a CTE for btree indexes associated with primary heap tables
         * selected above, filtering by exclusion patterns (if any) that match
         * btree index names.
         */
        appendPQExpBufferStr(&sql,
                             ", index (oid, nspname, relname, relpages) AS ("
                             "\nSELECT c.oid, r.nspname, c.relname, c.relpages "
                             "FROM relation r"
                             "\nINNER JOIN pg_catalog.pg_index i "
                             "ON r.oid = i.indrelid "
                             "INNER JOIN pg_catalog.pg_class c "
                             "ON i.indexrelid = c.oid "
                             "AND c.relpersistence != 't'");
        if (opts.excludeidx || opts.excludensp)
            appendPQExpBufferStr(&sql,
                                 "\nINNER JOIN pg_catalog.pg_namespace n "
                                 "ON c.relnamespace = n.oid"
                                 "\nLEFT OUTER JOIN exclude_pat ep "
                                 "ON (n.nspname ~ ep.nsp_regex OR ep.nsp_regex IS NULL) "
                                 "AND (c.relname ~ ep.rel_regex OR ep.rel_regex IS NULL) "
                                 "AND ep.btree_only"
                                 "\nWHERE ep.pattern_id IS NULL");
        else
            appendPQExpBufferStr(&sql,
                                 "\nWHERE true");
        appendPQExpBuffer(&sql,
                          " AND c.relam = %u "
                          "AND c.relkind = 'i'",
                          BTREE_AM_OID);
        if (opts.no_toast_expansion)
            appendPQExpBuffer(&sql,
                              " AND c.relnamespace != %u",
                              PG_TOAST_NAMESPACE);
        appendPQExpBufferStr(&sql, "\n)");
    }
 
    if (!opts.no_toast_expansion && !opts.no_btree_expansion)
    {
        /*
         * Include a CTE for btree indexes associated with toast tables of
         * primary heap tables selected above, filtering by exclusion patterns
         * (if any) that match the toast index names.
         */
        appendPQExpBufferStr(&sql,
                             ", toast_index (oid, nspname, relname, relpages) AS ("
                             "\nSELECT c.oid, 'pg_toast', c.relname, c.relpages "
                             "FROM toast t "
                             "INNER JOIN pg_catalog.pg_index i "
                             "ON t.oid = i.indrelid"
                             "\nINNER JOIN pg_catalog.pg_class c "
                             "ON i.indexrelid = c.oid "
                             "AND c.relpersistence != 't'");
        if (opts.excludeidx)
            appendPQExpBufferStr(&sql,
                                 "\nLEFT OUTER JOIN exclude_pat ep "
                                 "ON ('pg_toast' ~ ep.nsp_regex OR ep.nsp_regex IS NULL) "
                                 "AND (c.relname ~ ep.rel_regex OR ep.rel_regex IS NULL) "
                                 "AND ep.btree_only "
                                 "WHERE ep.pattern_id IS NULL");
        else
            appendPQExpBufferStr(&sql,
                                 "\nWHERE true");
        appendPQExpBuffer(&sql,
                          " AND c.relam = %u"
                          " AND c.relkind = 'i')",
                          BTREE_AM_OID);
    }
 
    /*
     * Roll-up distinct rows from CTEs.
     *
     * Relations that match more than one pattern may occur more than once in
     * the list, and indexes and toast for primary relations may also have
     * matched in their own right, so we rely on UNION to deduplicate the
     * list.
     */
    appendPQExpBufferStr(&sql,
                         "\nSELECT pattern_id, is_heap, is_btree, oid, nspname, relname, relpages "
                         "FROM (");
    appendPQExpBufferStr(&sql,
    /* Inclusion patterns that failed to match */
                         "\nSELECT pattern_id, is_heap, is_btree, "
                         "NULL::OID AS oid, "
                         "NULL::TEXT AS nspname, "
                         "NULL::TEXT AS relname, "
                         "NULL::INTEGER AS relpages"
                         "\nFROM relation "
                         "WHERE pattern_id IS NOT NULL "
                         "UNION"
    /* Primary relations */
                         "\nSELECT NULL::INTEGER AS pattern_id, "
                         "is_heap, is_btree, oid, nspname, relname, relpages "
                         "FROM relation");
    if (!opts.no_toast_expansion)
        appendPQExpBufferStr(&sql,
                             " UNION"
        /* Toast tables for primary relations */
                             "\nSELECT NULL::INTEGER AS pattern_id, TRUE AS is_heap, "
                             "FALSE AS is_btree, oid, nspname, relname, relpages "
                             "FROM toast");
    if (!opts.no_btree_expansion)
        appendPQExpBufferStr(&sql,
                             " UNION"
        /* Indexes for primary relations */
                             "\nSELECT NULL::INTEGER AS pattern_id, FALSE AS is_heap, "
                             "TRUE AS is_btree, oid, nspname, relname, relpages "
                             "FROM index");
    if (!opts.no_toast_expansion && !opts.no_btree_expansion)
        appendPQExpBufferStr(&sql,
                             " UNION"
        /* Indexes for toast relations */
                             "\nSELECT NULL::INTEGER AS pattern_id, FALSE AS is_heap, "
                             "TRUE AS is_btree, oid, nspname, relname, relpages "
                             "FROM toast_index");
    appendPQExpBufferStr(&sql,
                         "\n) AS combined_records "
                         "ORDER BY relpages DESC NULLS FIRST, oid");
 
    res = executeQuery(conn, sql.data, opts.echo);
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        pg_log_error("query failed: %s", PQerrorMessage(conn));
        pg_log_error_detail("Query was: %s", sql.data);
        disconnectDatabase(conn);
        exit(1);
    }
    termPQExpBuffer(&sql);
 
    ntups = PQntuples(res);
    for (i = 0; i < ntups; i++)
    {
        int         pattern_id = -1;
        bool        is_heap = false;
        bool        is_btree PG_USED_FOR_ASSERTS_ONLY = false;
        Oid         oid = InvalidOid;
        const char *nspname = NULL;
        const char *relname = NULL;
        int         relpages = 0;
 
        if (!PQgetisnull(res, i, 0))
            pattern_id = atoi(PQgetvalue(res, i, 0));
        if (!PQgetisnull(res, i, 1))
            is_heap = (PQgetvalue(res, i, 1)[0] == 't');
        if (!PQgetisnull(res, i, 2))
            is_btree = (PQgetvalue(res, i, 2)[0] == 't');
        if (!PQgetisnull(res, i, 3))
            oid = atooid(PQgetvalue(res, i, 3));
        if (!PQgetisnull(res, i, 4))
            nspname = PQgetvalue(res, i, 4);
        if (!PQgetisnull(res, i, 5))
            relname = PQgetvalue(res, i, 5);
        if (!PQgetisnull(res, i, 6))
            relpages = atoi(PQgetvalue(res, i, 6));
 
        if (pattern_id >= 0)
        {
            /*
             * Current record pertains to an inclusion pattern.  Record that
             * it matched.
             */
 
            if (pattern_id >= opts.include.len)
                pg_fatal("internal error: received unexpected relation pattern_id %d",
                         pattern_id);
 
            opts.include.data[pattern_id].matched = true;
        }
        else
        {
            /* Current record pertains to a relation */
 
            RelationInfo *rel = (RelationInfo *) pg_malloc0(sizeof(RelationInfo));
 
            Assert(OidIsValid(oid));
            Assert((is_heap && !is_btree) || (is_btree && !is_heap));
 
            rel->datinfo = dat;
            rel->reloid = oid;
            rel->is_heap = is_heap;
            rel->nspname = pstrdup(nspname);
            rel->relname = pstrdup(relname);
            rel->relpages = relpages;
            rel->blocks_to_check = relpages;
            if (is_heap && (opts.startblock >= 0 || opts.endblock >= 0))
            {
                /*
                 * We apply --startblock and --endblock to heap tables, but
                 * not btree indexes, and for progress purposes we need to
                 * track how many blocks we expect to check.
                 */
                if (opts.endblock >= 0 && rel->blocks_to_check > opts.endblock)
                    rel->blocks_to_check = opts.endblock + 1;
                if (opts.startblock >= 0)
                {
                    if (rel->blocks_to_check > opts.startblock)
                        rel->blocks_to_check -= opts.startblock;
                    else
                        rel->blocks_to_check = 0;
                }
            }
            *pagecount += rel->blocks_to_check;
 
            simple_ptr_list_append(relations, rel);
        }
    }
    PQclear(res);
}