vacuumdb.c

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/*-------------------------------------------------------------------------
 *
 * vacuumdb
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/bin/scripts/vacuumdb.c
 *
 *-------------------------------------------------------------------------
 */
 
#include "postgres_fe.h"
 
#include <limits.h>
 
#include "catalog/pg_class_d.h"
#include "common.h"
#include "common/connect.h"
#include "common/logging.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"
 
 
/* vacuum options controlled by user flags */
typedef struct vacuumingOptions
{
    bool        analyze_only;
    bool        verbose;
    bool        and_analyze;
    bool        full;
    bool        freeze;
    bool        disable_page_skipping;
    bool        skip_locked;
    int         min_xid_age;
    int         min_mxid_age;
    int         parallel_workers;   /* >= 0 indicates user specified the
                                     * parallel degree, otherwise -1 */
    bool        no_index_cleanup;
    bool        force_index_cleanup;
    bool        do_truncate;
    bool        process_main;
    bool        process_toast;
    bool        skip_database_stats;
    char       *buffer_usage_limit;
} vacuumingOptions;
 
/* object filter options */
typedef enum
{
    OBJFILTER_NONE = 0,         /* no filter used */
    OBJFILTER_ALL_DBS = (1 << 0),   /* -a | --all */
    OBJFILTER_DATABASE = (1 << 1),  /* -d | --dbname */
    OBJFILTER_TABLE = (1 << 2), /* -t | --table */
    OBJFILTER_SCHEMA = (1 << 3),    /* -n | --schema */
    OBJFILTER_SCHEMA_EXCLUDE = (1 << 4),    /* -N | --exclude-schema */
} VacObjFilter;
 
static VacObjFilter objfilter = OBJFILTER_NONE;
 
static void vacuum_one_database(ConnParams *cparams,
                                vacuumingOptions *vacopts,
                                int stage,
                                SimpleStringList *objects,
                                int concurrentCons,
                                const char *progname, bool echo, bool quiet);
 
static void vacuum_all_databases(ConnParams *cparams,
                                 vacuumingOptions *vacopts,
                                 bool analyze_in_stages,
                                 SimpleStringList *objects,
                                 int concurrentCons,
                                 const char *progname, bool echo, bool quiet);
 
static void prepare_vacuum_command(PQExpBuffer sql, int serverVersion,
                                   vacuumingOptions *vacopts, const char *table);
 
static void run_vacuum_command(PGconn *conn, const char *sql, bool echo,
                               const char *table);
 
static void help(const char *progname);
 
void        check_objfilter(void);
 
static char *escape_quotes(const char *src);
 
/* For analyze-in-stages mode */
#define ANALYZE_NO_STAGE    -1
#define ANALYZE_NUM_STAGES  3
 
 
int
main(int argc, char *argv[])
{
    static struct option long_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'},
        {"echo", no_argument, NULL, 'e'},
        {"quiet", no_argument, NULL, 'q'},
        {"dbname", required_argument, NULL, 'd'},
        {"analyze", no_argument, NULL, 'z'},
        {"analyze-only", no_argument, NULL, 'Z'},
        {"freeze", no_argument, NULL, 'F'},
        {"all", no_argument, NULL, 'a'},
        {"table", required_argument, NULL, 't'},
        {"full", no_argument, NULL, 'f'},
        {"verbose", no_argument, NULL, 'v'},
        {"jobs", required_argument, NULL, 'j'},
        {"parallel", required_argument, NULL, 'P'},
        {"schema", required_argument, NULL, 'n'},
        {"exclude-schema", required_argument, NULL, 'N'},
        {"maintenance-db", required_argument, NULL, 2},
        {"analyze-in-stages", no_argument, NULL, 3},
        {"disable-page-skipping", no_argument, NULL, 4},
        {"skip-locked", no_argument, NULL, 5},
        {"min-xid-age", required_argument, NULL, 6},
        {"min-mxid-age", required_argument, NULL, 7},
        {"no-index-cleanup", no_argument, NULL, 8},
        {"force-index-cleanup", no_argument, NULL, 9},
        {"no-truncate", no_argument, NULL, 10},
        {"no-process-toast", no_argument, NULL, 11},
        {"no-process-main", no_argument, NULL, 12},
        {"buffer-usage-limit", required_argument, NULL, 13},
        {NULL, 0, NULL, 0}
    };
 
    const char *progname;
    int         optindex;
    int         c;
    const char *dbname = NULL;
    const char *maintenance_db = NULL;
    char       *host = NULL;
    char       *port = NULL;
    char       *username = NULL;
    enum trivalue prompt_password = TRI_DEFAULT;
    ConnParams  cparams;
    bool        echo = false;
    bool        quiet = false;
    vacuumingOptions vacopts;
    bool        analyze_in_stages = false;
    SimpleStringList objects = {NULL, NULL};
    int         concurrentCons = 1;
    int         tbl_count = 0;
 
    /* initialize options */
    memset(&vacopts, 0, sizeof(vacopts));
    vacopts.parallel_workers = -1;
    vacopts.buffer_usage_limit = NULL;
    vacopts.no_index_cleanup = false;
    vacopts.force_index_cleanup = false;
    vacopts.do_truncate = true;
    vacopts.process_main = true;
    vacopts.process_toast = true;
 
    pg_logging_init(argv[0]);
    progname = get_progname(argv[0]);
    set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pgscripts"));
 
    handle_help_version_opts(argc, argv, "vacuumdb", help);
 
    while ((c = getopt_long(argc, argv, "ad:efFh:j:n:N:p:P:qt:U:vwWzZ", long_options, &optindex)) != -1)
    {
        switch (c)
        {
            case 'a':
                objfilter |= OBJFILTER_ALL_DBS;
                break;
            case 'd':
                objfilter |= OBJFILTER_DATABASE;
                dbname = pg_strdup(optarg);
                break;
            case 'e':
                echo = true;
                break;
            case 'f':
                vacopts.full = true;
                break;
            case 'F':
                vacopts.freeze = true;
                break;
            case 'h':
                host = pg_strdup(optarg);
                break;
            case 'j':
                if (!option_parse_int(optarg, "-j/--jobs", 1, INT_MAX,
                                      &concurrentCons))
                    exit(1);
                break;
            case 'n':
                objfilter |= OBJFILTER_SCHEMA;
                simple_string_list_append(&objects, optarg);
                break;
            case 'N':
                objfilter |= OBJFILTER_SCHEMA_EXCLUDE;
                simple_string_list_append(&objects, optarg);
                break;
            case 'p':
                port = pg_strdup(optarg);
                break;
            case 'P':
                if (!option_parse_int(optarg, "-P/--parallel", 0, INT_MAX,
                                      &vacopts.parallel_workers))
                    exit(1);
                break;
            case 'q':
                quiet = true;
                break;
            case 't':
                objfilter |= OBJFILTER_TABLE;
                simple_string_list_append(&objects, optarg);
                tbl_count++;
                break;
            case 'U':
                username = pg_strdup(optarg);
                break;
            case 'v':
                vacopts.verbose = true;
                break;
            case 'w':
                prompt_password = TRI_NO;
                break;
            case 'W':
                prompt_password = TRI_YES;
                break;
            case 'z':
                vacopts.and_analyze = true;
                break;
            case 'Z':
                vacopts.analyze_only = true;
                break;
            case 2:
                maintenance_db = pg_strdup(optarg);
                break;
            case 3:
                analyze_in_stages = vacopts.analyze_only = true;
                break;
            case 4:
                vacopts.disable_page_skipping = true;
                break;
            case 5:
                vacopts.skip_locked = true;
                break;
            case 6:
                if (!option_parse_int(optarg, "--min-xid-age", 1, INT_MAX,
                                      &vacopts.min_xid_age))
                    exit(1);
                break;
            case 7:
                if (!option_parse_int(optarg, "--min-mxid-age", 1, INT_MAX,
                                      &vacopts.min_mxid_age))
                    exit(1);
                break;
            case 8:
                vacopts.no_index_cleanup = true;
                break;
            case 9:
                vacopts.force_index_cleanup = true;
                break;
            case 10:
                vacopts.do_truncate = false;
                break;
            case 11:
                vacopts.process_toast = false;
                break;
            case 12:
                vacopts.process_main = false;
                break;
            case 13:
                vacopts.buffer_usage_limit = escape_quotes(optarg);
                break;
            default:
                /* getopt_long already emitted a complaint */
                pg_log_error_hint("Try \"%s --help\" for more information.", progname);
                exit(1);
        }
    }
 
    /*
     * Non-option argument specifies database name as long as it wasn't
     * already specified with -d / --dbname
     */
    if (optind < argc && dbname == NULL)
    {
        objfilter |= OBJFILTER_DATABASE;
        dbname = 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);
    }
 
    /*
     * Validate the combination of filters specified in the command-line
     * options.
     */
    check_objfilter();
 
    if (vacopts.analyze_only)
    {
        if (vacopts.full)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "full");
        if (vacopts.freeze)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "freeze");
        if (vacopts.disable_page_skipping)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "disable-page-skipping");
        if (vacopts.no_index_cleanup)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "no-index-cleanup");
        if (vacopts.force_index_cleanup)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "force-index-cleanup");
        if (!vacopts.do_truncate)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "no-truncate");
        if (!vacopts.process_main)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "no-process-main");
        if (!vacopts.process_toast)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "no-process-toast");
        /* allow 'and_analyze' with 'analyze_only' */
    }
 
    /* Prohibit full and analyze_only options with parallel option */
    if (vacopts.parallel_workers >= 0)
    {
        if (vacopts.analyze_only)
            pg_fatal("cannot use the \"%s\" option when performing only analyze",
                     "parallel");
        if (vacopts.full)
            pg_fatal("cannot use the \"%s\" option when performing full vacuum",
                     "parallel");
    }
 
    /* Prohibit --no-index-cleanup and --force-index-cleanup together */
    if (vacopts.no_index_cleanup && vacopts.force_index_cleanup)
        pg_fatal("cannot use the \"%s\" option with the \"%s\" option",
                 "no-index-cleanup", "force-index-cleanup");
 
    /*
     * buffer-usage-limit is not allowed with VACUUM FULL unless ANALYZE is
     * included too.
     */
    if (vacopts.buffer_usage_limit && vacopts.full && !vacopts.and_analyze)
        pg_fatal("cannot use the \"%s\" option with the \"%s\" option",
                 "buffer-usage-limit", "full");
 
    /* fill cparams except for dbname, which is set below */
    cparams.pghost = host;
    cparams.pgport = port;
    cparams.pguser = username;
    cparams.prompt_password = prompt_password;
    cparams.override_dbname = NULL;
 
    setup_cancel_handler(NULL);
 
    /* Avoid opening extra connections. */
    if (tbl_count && (concurrentCons > tbl_count))
        concurrentCons = tbl_count;
 
    if (objfilter & OBJFILTER_ALL_DBS)
    {
        cparams.dbname = maintenance_db;
 
        vacuum_all_databases(&cparams, &vacopts,
                             analyze_in_stages,
                             &objects,
                             concurrentCons,
                             progname, echo, quiet);
    }
    else
    {
        if (dbname == NULL)
        {
            if (getenv("PGDATABASE"))
                dbname = getenv("PGDATABASE");
            else if (getenv("PGUSER"))
                dbname = getenv("PGUSER");
            else
                dbname = get_user_name_or_exit(progname);
        }
 
        cparams.dbname = dbname;
 
        if (analyze_in_stages)
        {
            int         stage;
 
            for (stage = 0; stage < ANALYZE_NUM_STAGES; stage++)
            {
                vacuum_one_database(&cparams, &vacopts,
                                    stage,
                                    &objects,
                                    concurrentCons,
                                    progname, echo, quiet);
            }
        }
        else
            vacuum_one_database(&cparams, &vacopts,
                                ANALYZE_NO_STAGE,
                                &objects,
                                concurrentCons,
                                progname, echo, quiet);
    }
 
    exit(0);
}
 
/*
 * Verify that the filters used at command line are compatible.
 */
void
check_objfilter(void)
{
    if ((objfilter & OBJFILTER_ALL_DBS) &&
        (objfilter & OBJFILTER_DATABASE))
        pg_fatal("cannot vacuum all databases and a specific one at the same time");
 
    if ((objfilter & OBJFILTER_TABLE) &&
        (objfilter & OBJFILTER_SCHEMA))
        pg_fatal("cannot vacuum all tables in schema(s) and specific table(s) at the same time");
 
    if ((objfilter & OBJFILTER_TABLE) &&
        (objfilter & OBJFILTER_SCHEMA_EXCLUDE))
        pg_fatal("cannot vacuum specific table(s) and exclude schema(s) at the same time");
 
    if ((objfilter & OBJFILTER_SCHEMA) &&
        (objfilter & OBJFILTER_SCHEMA_EXCLUDE))
        pg_fatal("cannot vacuum all tables in schema(s) and exclude schema(s) at the same time");
}
 
/*
 * Returns a newly malloc'd version of 'src' with escaped single quotes and
 * backslashes.
 */
static char *
escape_quotes(const char *src)
{
    char       *result = escape_single_quotes_ascii(src);
 
    if (!result)
        pg_fatal("out of memory");
    return result;
}
 
/*
 * vacuum_one_database
 *
 * Process tables in the given database.  If the 'objects' list is empty,
 * process all tables in the database.
 *
 * Note that this function is only concerned with running exactly one stage
 * when in analyze-in-stages mode; caller must iterate on us if necessary.
 *
 * If concurrentCons is > 1, multiple connections are used to vacuum tables
 * in parallel.
 */
static void
vacuum_one_database(ConnParams *cparams,
                    vacuumingOptions *vacopts,
                    int stage,
                    SimpleStringList *objects,
                    int concurrentCons,
                    const char *progname, bool echo, bool quiet)
{
    PQExpBufferData sql;
    PQExpBufferData buf;
    PQExpBufferData catalog_query;
    PGresult   *res;
    PGconn     *conn;
    SimpleStringListCell *cell;
    ParallelSlotArray *sa;
    SimpleStringList dbtables = {NULL, NULL};
    int         i;
    int         ntups;
    bool        failed = false;
    bool        objects_listed = false;
    const char *initcmd;
    const char *stage_commands[] = {
        "SET default_statistics_target=1; SET vacuum_cost_delay=0;",
        "SET default_statistics_target=10; RESET vacuum_cost_delay;",
        "RESET default_statistics_target;"
    };
    const char *stage_messages[] = {
        gettext_noop("Generating minimal optimizer statistics (1 target)"),
        gettext_noop("Generating medium optimizer statistics (10 targets)"),
        gettext_noop("Generating default (full) optimizer statistics")
    };
 
    Assert(stage == ANALYZE_NO_STAGE ||
           (stage >= 0 && stage < ANALYZE_NUM_STAGES));
 
    conn = connectDatabase(cparams, progname, echo, false, true);
 
    if (vacopts->disable_page_skipping && PQserverVersion(conn) < 90600)
    {
        PQfinish(conn);
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "disable-page-skipping", "9.6");
    }
 
    if (vacopts->no_index_cleanup && PQserverVersion(conn) < 120000)
    {
        PQfinish(conn);
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "no-index-cleanup", "12");
    }
 
    if (vacopts->force_index_cleanup && PQserverVersion(conn) < 120000)
    {
        PQfinish(conn);
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "force-index-cleanup", "12");
    }
 
    if (!vacopts->do_truncate && PQserverVersion(conn) < 120000)
    {
        PQfinish(conn);
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "no-truncate", "12");
    }
 
    if (!vacopts->process_main && PQserverVersion(conn) < 160000)
    {
        PQfinish(conn);
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "no-process-main", "16");
    }
 
    if (!vacopts->process_toast && PQserverVersion(conn) < 140000)
    {
        PQfinish(conn);
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "no-process-toast", "14");
    }
 
    if (vacopts->skip_locked && PQserverVersion(conn) < 120000)
    {
        PQfinish(conn);
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "skip-locked", "12");
    }
 
    if (vacopts->min_xid_age != 0 && PQserverVersion(conn) < 90600)
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "--min-xid-age", "9.6");
 
    if (vacopts->min_mxid_age != 0 && PQserverVersion(conn) < 90600)
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "--min-mxid-age", "9.6");
 
    if (vacopts->parallel_workers >= 0 && PQserverVersion(conn) < 130000)
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "--parallel", "13");
 
    if (vacopts->buffer_usage_limit && PQserverVersion(conn) < 160000)
        pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
                 "--buffer-usage-limit", "16");
 
    /* skip_database_stats is used automatically if server supports it */
    vacopts->skip_database_stats = (PQserverVersion(conn) >= 160000);
 
    if (!quiet)
    {
        if (stage != ANALYZE_NO_STAGE)
            printf(_("%s: processing database \"%s\": %s\n"),
                   progname, PQdb(conn), _(stage_messages[stage]));
        else
            printf(_("%s: vacuuming database \"%s\"\n"),
                   progname, PQdb(conn));
        fflush(stdout);
    }
 
    /*
     * Prepare the list of tables to process by querying the catalogs.
     *
     * Since we execute the constructed query with the default search_path
     * (which could be unsafe), everything in this query MUST be fully
     * qualified.
     *
     * First, build a WITH clause for the catalog query if any tables were
     * specified, with a set of values made of relation names and their
     * optional set of columns.  This is used to match any provided column
     * lists with the generated qualified identifiers and to filter for the
     * tables provided via --table.  If a listed table does not exist, the
     * catalog query will fail.
     */
    initPQExpBuffer(&catalog_query);
    for (cell = objects ? objects->head : NULL; cell; cell = cell->next)
    {
        char       *just_table = NULL;
        const char *just_columns = NULL;
 
        if (!objects_listed)
        {
            appendPQExpBufferStr(&catalog_query,
                                 "WITH listed_objects (object_oid, column_list) "
                                 "AS (\n  VALUES (");
            objects_listed = true;
        }
        else
            appendPQExpBufferStr(&catalog_query, ",\n  (");
 
        if (objfilter & (OBJFILTER_SCHEMA | OBJFILTER_SCHEMA_EXCLUDE))
        {
            appendStringLiteralConn(&catalog_query, cell->val, conn);
            appendPQExpBufferStr(&catalog_query, "::pg_catalog.regnamespace, ");
        }
 
        if (objfilter & OBJFILTER_TABLE)
        {
            /*
             * Split relation and column names given by the user, this is used
             * to feed the CTE with values on which are performed pre-run
             * validity checks as well.  For now these happen only on the
             * relation name.
             */
            splitTableColumnsSpec(cell->val, PQclientEncoding(conn),
                                  &just_table, &just_columns);
 
            appendStringLiteralConn(&catalog_query, just_table, conn);
            appendPQExpBufferStr(&catalog_query, "::pg_catalog.regclass, ");
        }
 
        if (just_columns && just_columns[0] != '\0')
            appendStringLiteralConn(&catalog_query, just_columns, conn);
        else
            appendPQExpBufferStr(&catalog_query, "NULL");
 
        appendPQExpBufferStr(&catalog_query, "::pg_catalog.text)");
 
        pg_free(just_table);
    }
 
    /* Finish formatting the CTE */
    if (objects_listed)
        appendPQExpBufferStr(&catalog_query, "\n)\n");
 
    appendPQExpBufferStr(&catalog_query, "SELECT c.relname, ns.nspname");
 
    if (objects_listed)
        appendPQExpBufferStr(&catalog_query, ", listed_objects.column_list");
 
    appendPQExpBufferStr(&catalog_query,
                         " FROM pg_catalog.pg_class c\n"
                         " JOIN pg_catalog.pg_namespace ns"
                         " ON c.relnamespace OPERATOR(pg_catalog.=) ns.oid\n"
                         " LEFT JOIN pg_catalog.pg_class t"
                         " ON c.reltoastrelid OPERATOR(pg_catalog.=) t.oid\n");
 
    /*
     * Used to match the tables or schemas listed by the user, completing the
     * JOIN clause.
     */
    if (objects_listed)
    {
        appendPQExpBufferStr(&catalog_query, " LEFT JOIN listed_objects"
                             " ON listed_objects.object_oid"
                             " OPERATOR(pg_catalog.=) ");
 
        if (objfilter & OBJFILTER_TABLE)
            appendPQExpBufferStr(&catalog_query, "c.oid\n");
        else
            appendPQExpBufferStr(&catalog_query, "ns.oid\n");
    }
 
    /*
     * Exclude temporary tables, beginning the WHERE clause.
     */
    appendPQExpBufferStr(&catalog_query,
                         " WHERE c.relpersistence OPERATOR(pg_catalog.!=) "
                         CppAsString2(RELPERSISTENCE_TEMP) "\n");
 
    /*
     * Used to match the tables or schemas listed by the user, for the WHERE
     * clause.
     */
    if (objects_listed)
    {
        if (objfilter & OBJFILTER_SCHEMA_EXCLUDE)
            appendPQExpBuffer(&catalog_query,
                              " AND listed_objects.object_oid IS NULL\n");
        else
            appendPQExpBuffer(&catalog_query,
                              " AND listed_objects.object_oid IS NOT NULL\n");
    }
 
    /*
     * If no tables were listed, filter for the relevant relation types.  If
     * tables were given via --table, don't bother filtering by relation type.
     * Instead, let the server decide whether a given relation can be
     * processed in which case the user will know about it.
     */
    if ((objfilter & OBJFILTER_TABLE) == 0)
    {
        appendPQExpBuffer(&catalog_query,
                          " AND c.relkind OPERATOR(pg_catalog.=) ANY (array["
                          CppAsString2(RELKIND_RELATION) ", "
                          CppAsString2(RELKIND_MATVIEW) "])\n");
    }
 
    /*
     * For --min-xid-age and --min-mxid-age, the age of the relation is the
     * greatest of the ages of the main relation and its associated TOAST
     * table.  The commands generated by vacuumdb will also process the TOAST
     * table for the relation if necessary, so it does not need to be
     * considered separately.
     */
    if (vacopts->min_xid_age != 0)
    {
        appendPQExpBuffer(&catalog_query,
                          " AND GREATEST(pg_catalog.age(c.relfrozenxid),"
                          " pg_catalog.age(t.relfrozenxid)) "
                          " OPERATOR(pg_catalog.>=) '%d'::pg_catalog.int4\n"
                          " AND c.relfrozenxid OPERATOR(pg_catalog.!=)"
                          " '0'::pg_catalog.xid\n",
                          vacopts->min_xid_age);
    }
 
    if (vacopts->min_mxid_age != 0)
    {
        appendPQExpBuffer(&catalog_query,
                          " AND GREATEST(pg_catalog.mxid_age(c.relminmxid),"
                          " pg_catalog.mxid_age(t.relminmxid)) OPERATOR(pg_catalog.>=)"
                          " '%d'::pg_catalog.int4\n"
                          " AND c.relminmxid OPERATOR(pg_catalog.!=)"
                          " '0'::pg_catalog.xid\n",
                          vacopts->min_mxid_age);
    }
 
    /*
     * Execute the catalog query.  We use the default search_path for this
     * query for consistency with table lookups done elsewhere by the user.
     */
    appendPQExpBufferStr(&catalog_query, " ORDER BY c.relpages DESC;");
    executeCommand(conn, "RESET search_path;", echo);
    res = executeQuery(conn, catalog_query.data, echo);
    termPQExpBuffer(&catalog_query);
    PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL, echo));
 
    /*
     * If no rows are returned, there are no matching tables, so we are done.
     */
    ntups = PQntuples(res);
    if (ntups == 0)
    {
        PQclear(res);
        PQfinish(conn);
        return;
    }
 
    /*
     * Build qualified identifiers for each table, including the column list
     * if given.
     */
    initPQExpBuffer(&buf);
    for (i = 0; i < ntups; i++)
    {
        appendPQExpBufferStr(&buf,
                             fmtQualifiedId(PQgetvalue(res, i, 1),
                                            PQgetvalue(res, i, 0)));
 
        if (objects_listed && !PQgetisnull(res, i, 2))
            appendPQExpBufferStr(&buf, PQgetvalue(res, i, 2));
 
        simple_string_list_append(&dbtables, buf.data);
        resetPQExpBuffer(&buf);
    }
    termPQExpBuffer(&buf);
    PQclear(res);
 
    /*
     * Ensure concurrentCons is sane.  If there are more connections than
     * vacuumable relations, we don't need to use them all.
     */
    if (concurrentCons > ntups)
        concurrentCons = ntups;
    if (concurrentCons <= 0)
        concurrentCons = 1;
 
    /*
     * All slots need to be prepared to run the appropriate analyze stage, if
     * caller requested that mode.  We have to prepare the initial connection
     * ourselves before setting up the slots.
     */
    if (stage == ANALYZE_NO_STAGE)
        initcmd = NULL;
    else
    {
        initcmd = stage_commands[stage];
        executeCommand(conn, initcmd, echo);
    }
 
    /*
     * Setup the database connections. We reuse the connection we already have
     * for the first slot.  If not in parallel mode, the first slot in the
     * array contains the connection.
     */
    sa = ParallelSlotsSetup(concurrentCons, cparams, progname, echo, initcmd);
    ParallelSlotsAdoptConn(sa, conn);
 
    initPQExpBuffer(&sql);
 
    cell = dbtables.head;
    do
    {
        const char *tabname = cell->val;
        ParallelSlot *free_slot;
 
        if (CancelRequested)
        {
            failed = true;
            goto finish;
        }
 
        free_slot = ParallelSlotsGetIdle(sa, NULL);
        if (!free_slot)
        {
            failed = true;
            goto finish;
        }
 
        prepare_vacuum_command(&sql, PQserverVersion(free_slot->connection),
                               vacopts, tabname);
 
        /*
         * Execute the vacuum.  All errors are handled in processQueryResult
         * through ParallelSlotsGetIdle.
         */
        ParallelSlotSetHandler(free_slot, TableCommandResultHandler, NULL);
        run_vacuum_command(free_slot->connection, sql.data,
                           echo, tabname);
 
        cell = cell->next;
    } while (cell != NULL);
 
    if (!ParallelSlotsWaitCompletion(sa))
    {
        failed = true;
        goto finish;
    }
 
    /* If we used SKIP_DATABASE_STATS, mop up with ONLY_DATABASE_STATS */
    if (vacopts->skip_database_stats && stage == ANALYZE_NO_STAGE)
    {
        const char *cmd = "VACUUM (ONLY_DATABASE_STATS);";
        ParallelSlot *free_slot = ParallelSlotsGetIdle(sa, NULL);
 
        if (!free_slot)
        {
            failed = true;
            goto finish;
        }
 
        ParallelSlotSetHandler(free_slot, TableCommandResultHandler, NULL);
        run_vacuum_command(free_slot->connection, cmd, echo, NULL);
 
        if (!ParallelSlotsWaitCompletion(sa))
            failed = true;
    }
 
finish:
    ParallelSlotsTerminate(sa);
    pg_free(sa);
 
    termPQExpBuffer(&sql);
 
    if (failed)
        exit(1);
}
 
/*
 * Vacuum/analyze all connectable databases.
 *
 * In analyze-in-stages mode, we process all databases in one stage before
 * moving on to the next stage.  That ensure minimal stats are available
 * quickly everywhere before generating more detailed ones.
 */
static void
vacuum_all_databases(ConnParams *cparams,
                     vacuumingOptions *vacopts,
                     bool analyze_in_stages,
                     SimpleStringList *objects,
                     int concurrentCons,
                     const char *progname, bool echo, bool quiet)
{
    PGconn     *conn;
    PGresult   *result;
    int         stage;
    int         i;
 
    conn = connectMaintenanceDatabase(cparams, progname, echo);
    result = executeQuery(conn,
                          "SELECT datname FROM pg_database WHERE datallowconn AND datconnlimit <> -2 ORDER BY 1;",
                          echo);
    PQfinish(conn);
 
    if (analyze_in_stages)
    {
        /*
         * When analyzing all databases in stages, we analyze them all in the
         * fastest stage first, so that initial statistics become available
         * for all of them as soon as possible.
         *
         * This means we establish several times as many connections, but
         * that's a secondary consideration.
         */
        for (stage = 0; stage < ANALYZE_NUM_STAGES; stage++)
        {
            for (i = 0; i < PQntuples(result); i++)
            {
                cparams->override_dbname = PQgetvalue(result, i, 0);
 
                vacuum_one_database(cparams, vacopts,
                                    stage,
                                    objects,
                                    concurrentCons,
                                    progname, echo, quiet);
            }
        }
    }
    else
    {
        for (i = 0; i < PQntuples(result); i++)
        {
            cparams->override_dbname = PQgetvalue(result, i, 0);
 
            vacuum_one_database(cparams, vacopts,
                                ANALYZE_NO_STAGE,
                                objects,
                                concurrentCons,
                                progname, echo, quiet);
        }
    }
 
    PQclear(result);
}
 
/*
 * Construct a vacuum/analyze command to run based on the given options, in the
 * given string buffer, which may contain previous garbage.
 *
 * The table name used must be already properly quoted.  The command generated
 * depends on the server version involved and it is semicolon-terminated.
 */
static void
prepare_vacuum_command(PQExpBuffer sql, int serverVersion,
                       vacuumingOptions *vacopts, const char *table)
{
    const char *paren = " (";
    const char *comma = ", ";
    const char *sep = paren;
 
    resetPQExpBuffer(sql);
 
    if (vacopts->analyze_only)
    {
        appendPQExpBufferStr(sql, "ANALYZE");
 
        /* parenthesized grammar of ANALYZE is supported since v11 */
        if (serverVersion >= 110000)
        {
            if (vacopts->skip_locked)
            {
                /* SKIP_LOCKED is supported since v12 */
                Assert(serverVersion >= 120000);
                appendPQExpBuffer(sql, "%sSKIP_LOCKED", sep);
                sep = comma;
            }
            if (vacopts->verbose)
            {
                appendPQExpBuffer(sql, "%sVERBOSE", sep);
                sep = comma;
            }
            if (vacopts->buffer_usage_limit)
            {
                Assert(serverVersion >= 160000);
                appendPQExpBuffer(sql, "%sBUFFER_USAGE_LIMIT '%s'", sep,
                                  vacopts->buffer_usage_limit);
                sep = comma;
            }
            if (sep != paren)
                appendPQExpBufferChar(sql, ')');
        }
        else
        {
            if (vacopts->verbose)
                appendPQExpBufferStr(sql, " VERBOSE");
        }
    }
    else
    {
        appendPQExpBufferStr(sql, "VACUUM");
 
        /* parenthesized grammar of VACUUM is supported since v9.0 */
        if (serverVersion >= 90000)
        {
            if (vacopts->disable_page_skipping)
            {
                /* DISABLE_PAGE_SKIPPING is supported since v9.6 */
                Assert(serverVersion >= 90600);
                appendPQExpBuffer(sql, "%sDISABLE_PAGE_SKIPPING", sep);
                sep = comma;
            }
            if (vacopts->no_index_cleanup)
            {
                /* "INDEX_CLEANUP FALSE" has been supported since v12 */
                Assert(serverVersion >= 120000);
                Assert(!vacopts->force_index_cleanup);
                appendPQExpBuffer(sql, "%sINDEX_CLEANUP FALSE", sep);
                sep = comma;
            }
            if (vacopts->force_index_cleanup)
            {
                /* "INDEX_CLEANUP TRUE" has been supported since v12 */
                Assert(serverVersion >= 120000);
                Assert(!vacopts->no_index_cleanup);
                appendPQExpBuffer(sql, "%sINDEX_CLEANUP TRUE", sep);
                sep = comma;
            }
            if (!vacopts->do_truncate)
            {
                /* TRUNCATE is supported since v12 */
                Assert(serverVersion >= 120000);
                appendPQExpBuffer(sql, "%sTRUNCATE FALSE", sep);
                sep = comma;
            }
            if (!vacopts->process_main)
            {
                /* PROCESS_MAIN is supported since v16 */
                Assert(serverVersion >= 160000);
                appendPQExpBuffer(sql, "%sPROCESS_MAIN FALSE", sep);
                sep = comma;
            }
            if (!vacopts->process_toast)
            {
                /* PROCESS_TOAST is supported since v14 */
                Assert(serverVersion >= 140000);
                appendPQExpBuffer(sql, "%sPROCESS_TOAST FALSE", sep);
                sep = comma;
            }
            if (vacopts->skip_database_stats)
            {
                /* SKIP_DATABASE_STATS is supported since v16 */
                Assert(serverVersion >= 160000);
                appendPQExpBuffer(sql, "%sSKIP_DATABASE_STATS", sep);
                sep = comma;
            }
            if (vacopts->skip_locked)
            {
                /* SKIP_LOCKED is supported since v12 */
                Assert(serverVersion >= 120000);
                appendPQExpBuffer(sql, "%sSKIP_LOCKED", sep);
                sep = comma;
            }
            if (vacopts->full)
            {
                appendPQExpBuffer(sql, "%sFULL", sep);
                sep = comma;
            }
            if (vacopts->freeze)
            {
                appendPQExpBuffer(sql, "%sFREEZE", sep);
                sep = comma;
            }
            if (vacopts->verbose)
            {
                appendPQExpBuffer(sql, "%sVERBOSE", sep);
                sep = comma;
            }
            if (vacopts->and_analyze)
            {
                appendPQExpBuffer(sql, "%sANALYZE", sep);
                sep = comma;
            }
            if (vacopts->parallel_workers >= 0)
            {
                /* PARALLEL is supported since v13 */
                Assert(serverVersion >= 130000);
                appendPQExpBuffer(sql, "%sPARALLEL %d", sep,
                                  vacopts->parallel_workers);
                sep = comma;
            }
            if (vacopts->buffer_usage_limit)
            {
                Assert(serverVersion >= 160000);
                appendPQExpBuffer(sql, "%sBUFFER_USAGE_LIMIT '%s'", sep,
                                  vacopts->buffer_usage_limit);
                sep = comma;
            }
            if (sep != paren)
                appendPQExpBufferChar(sql, ')');
        }
        else
        {
            if (vacopts->full)
                appendPQExpBufferStr(sql, " FULL");
            if (vacopts->freeze)
                appendPQExpBufferStr(sql, " FREEZE");
            if (vacopts->verbose)
                appendPQExpBufferStr(sql, " VERBOSE");
            if (vacopts->and_analyze)
                appendPQExpBufferStr(sql, " ANALYZE");
        }
    }
 
    appendPQExpBuffer(sql, " %s;", table);
}
 
/*
 * Send a vacuum/analyze command to the server, returning after sending the
 * command.
 *
 * Any errors during command execution are reported to stderr.
 */
static void
run_vacuum_command(PGconn *conn, const char *sql, bool echo,
                   const char *table)
{
    bool        status;
 
    if (echo)
        printf("%s\n", sql);
 
    status = PQsendQuery(conn, sql) == 1;
 
    if (!status)
    {
        if (table)
            pg_log_error("vacuuming of table \"%s\" in database \"%s\" failed: %s",
                         table, PQdb(conn), PQerrorMessage(conn));
        else
            pg_log_error("vacuuming of database \"%s\" failed: %s",
                         PQdb(conn), PQerrorMessage(conn));
    }
}
 
static void
help(const char *progname)
{
    printf(_("%s cleans and analyzes a PostgreSQL database.\n\n"), progname);
    printf(_("Usage:\n"));
    printf(_("  %s [OPTION]... [DBNAME]\n"), progname);
    printf(_("\nOptions:\n"));
    printf(_("  -a, --all                       vacuum all databases\n"));
    printf(_("      --buffer-usage-limit=SIZE   size of ring buffer used for vacuum\n"));
    printf(_("  -d, --dbname=DBNAME             database to vacuum\n"));
    printf(_("      --disable-page-skipping     disable all page-skipping behavior\n"));
    printf(_("  -e, --echo                      show the commands being sent to the server\n"));
    printf(_("  -f, --full                      do full vacuuming\n"));
    printf(_("  -F, --freeze                    freeze row transaction information\n"));
    printf(_("      --force-index-cleanup       always remove index entries that point to dead tuples\n"));
    printf(_("  -j, --jobs=NUM                  use this many concurrent connections to vacuum\n"));
    printf(_("      --min-mxid-age=MXID_AGE     minimum multixact ID age of tables to vacuum\n"));
    printf(_("      --min-xid-age=XID_AGE       minimum transaction ID age of tables to vacuum\n"));
    printf(_("      --no-index-cleanup          don't remove index entries that point to dead tuples\n"));
    printf(_("      --no-process-main           skip the main relation\n"));
    printf(_("      --no-process-toast          skip the TOAST table associated with the table to vacuum\n"));
    printf(_("      --no-truncate               don't truncate empty pages at the end of the table\n"));
    printf(_("  -n, --schema=SCHEMA             vacuum tables in the specified schema(s) only\n"));
    printf(_("  -N, --exclude-schema=SCHEMA     do not vacuum tables in the specified schema(s)\n"));
    printf(_("  -P, --parallel=PARALLEL_WORKERS use this many background workers for vacuum, if available\n"));
    printf(_("  -q, --quiet                     don't write any messages\n"));
    printf(_("      --skip-locked               skip relations that cannot be immediately locked\n"));
    printf(_("  -t, --table='TABLE[(COLUMNS)]'  vacuum specific table(s) only\n"));
    printf(_("  -v, --verbose                   write a lot of output\n"));
    printf(_("  -V, --version                   output version information, then exit\n"));
    printf(_("  -z, --analyze                   update optimizer statistics\n"));
    printf(_("  -Z, --analyze-only              only update optimizer statistics; no vacuum\n"));
    printf(_("      --analyze-in-stages         only update optimizer statistics, in multiple\n"
             "                                  stages for faster results; no vacuum\n"));
    printf(_("  -?, --help                      show this help, then exit\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(_("\nRead the description of the SQL command VACUUM for details.\n"));
    printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
}