pgstatfuncs.c

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/*-------------------------------------------------------------------------
 *
 * pgstatfuncs.c
 *    Functions for accessing various forms of statistics data
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/utils/adt/pgstatfuncs.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "access/htup_details.h"
#include "access/xlog.h"
#include "access/xlogprefetcher.h"
#include "catalog/catalog.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_type.h"
#include "common/ip.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/bgworker.h"
#include "replication/logicallauncher.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/timestamp.h"
 
#define UINT32_ACCESS_ONCE(var)      ((uint32)(*((volatile uint32 *)&(var))))
 
#define HAS_PGSTAT_PERMISSIONS(role)     (has_privs_of_role(GetUserId(), ROLE_PG_READ_ALL_STATS) || has_privs_of_role(GetUserId(), role))
 
#define PG_STAT_GET_RELENTRY_INT64(stat)                        \
Datum                                                           \
CppConcat(pg_stat_get_,stat)(PG_FUNCTION_ARGS)                  \
{                                                               \
    Oid         relid = PG_GETARG_OID(0);                       \
    int64       result;                                         \
    PgStat_StatTabEntry *tabentry;                              \
                                                                \
    if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL) \
        result = 0;                                             \
    else                                                        \
        result = (int64) (tabentry->stat);                      \
                                                                \
    PG_RETURN_INT64(result);                                    \
}
 
/* pg_stat_get_analyze_count */
PG_STAT_GET_RELENTRY_INT64(analyze_count)
 
/* pg_stat_get_autoanalyze_count */
PG_STAT_GET_RELENTRY_INT64(autoanalyze_count)
 
/* pg_stat_get_autovacuum_count */
PG_STAT_GET_RELENTRY_INT64(autovacuum_count)
 
/* pg_stat_get_blocks_fetched */
PG_STAT_GET_RELENTRY_INT64(blocks_fetched)
 
/* pg_stat_get_blocks_hit */
PG_STAT_GET_RELENTRY_INT64(blocks_hit)
 
/* pg_stat_get_dead_tuples */
PG_STAT_GET_RELENTRY_INT64(dead_tuples)
 
/* pg_stat_get_ins_since_vacuum */
PG_STAT_GET_RELENTRY_INT64(ins_since_vacuum)
 
/* pg_stat_get_live_tuples */
PG_STAT_GET_RELENTRY_INT64(live_tuples)
 
/* pg_stat_get_mod_since_analyze */
PG_STAT_GET_RELENTRY_INT64(mod_since_analyze)
 
/* pg_stat_get_numscans */
PG_STAT_GET_RELENTRY_INT64(numscans)
 
/* pg_stat_get_tuples_deleted */
PG_STAT_GET_RELENTRY_INT64(tuples_deleted)
 
/* pg_stat_get_tuples_fetched */
PG_STAT_GET_RELENTRY_INT64(tuples_fetched)
 
/* pg_stat_get_tuples_hot_updated */
PG_STAT_GET_RELENTRY_INT64(tuples_hot_updated)
 
/* pg_stat_get_tuples_newpage_updated */
PG_STAT_GET_RELENTRY_INT64(tuples_newpage_updated)
 
/* pg_stat_get_tuples_inserted */
PG_STAT_GET_RELENTRY_INT64(tuples_inserted)
 
/* pg_stat_get_tuples_returned */
PG_STAT_GET_RELENTRY_INT64(tuples_returned)
 
/* pg_stat_get_tuples_updated */
PG_STAT_GET_RELENTRY_INT64(tuples_updated)
 
/* pg_stat_get_vacuum_count */
PG_STAT_GET_RELENTRY_INT64(vacuum_count)
 
#define PG_STAT_GET_RELENTRY_TIMESTAMPTZ(stat)                  \
Datum                                                           \
CppConcat(pg_stat_get_,stat)(PG_FUNCTION_ARGS)                  \
{                                                               \
    Oid         relid = PG_GETARG_OID(0);                       \
    TimestampTz result;                                         \
    PgStat_StatTabEntry *tabentry;                              \
                                                                \
    if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL) \
        result = 0;                                             \
    else                                                        \
        result = tabentry->stat;                                \
                                                                \
    if (result == 0)                                            \
        PG_RETURN_NULL();                                       \
    else                                                        \
        PG_RETURN_TIMESTAMPTZ(result);                          \
}
 
/* pg_stat_get_last_analyze_time */
PG_STAT_GET_RELENTRY_TIMESTAMPTZ(last_analyze_time)
 
/* pg_stat_get_last_autoanalyze_time */
PG_STAT_GET_RELENTRY_TIMESTAMPTZ(last_autoanalyze_time)
 
/* pg_stat_get_last_autovacuum_time */
PG_STAT_GET_RELENTRY_TIMESTAMPTZ(last_autovacuum_time)
 
/* pg_stat_get_last_vacuum_time */
PG_STAT_GET_RELENTRY_TIMESTAMPTZ(last_vacuum_time)
 
/* pg_stat_get_lastscan */
PG_STAT_GET_RELENTRY_TIMESTAMPTZ(lastscan)
 
Datum
pg_stat_get_function_calls(PG_FUNCTION_ARGS)
{
    Oid         funcid = PG_GETARG_OID(0);
    PgStat_StatFuncEntry *funcentry;
 
    if ((funcentry = pgstat_fetch_stat_funcentry(funcid)) == NULL)
        PG_RETURN_NULL();
    PG_RETURN_INT64(funcentry->numcalls);
}
 
/* convert counter from microsec to millisec for display */
#define PG_STAT_GET_FUNCENTRY_FLOAT8_MS(stat)                       \
Datum                                                               \
CppConcat(pg_stat_get_function_,stat)(PG_FUNCTION_ARGS)             \
{                                                                   \
    Oid         funcid = PG_GETARG_OID(0);                          \
    double      result;                                             \
    PgStat_StatFuncEntry *funcentry;                                \
                                                                    \
    if ((funcentry = pgstat_fetch_stat_funcentry(funcid)) == NULL)  \
        PG_RETURN_NULL();                                           \
    result = ((double) funcentry->stat) / 1000.0;                   \
    PG_RETURN_FLOAT8(result);                                       \
}
 
/* pg_stat_get_function_total_time */
PG_STAT_GET_FUNCENTRY_FLOAT8_MS(total_time)
 
/* pg_stat_get_function_self_time */
PG_STAT_GET_FUNCENTRY_FLOAT8_MS(self_time)
 
Datum
pg_stat_get_backend_idset(PG_FUNCTION_ARGS)
{
    FuncCallContext *funcctx;
    int        *fctx;
 
    /* stuff done only on the first call of the function */
    if (SRF_IS_FIRSTCALL())
    {
        /* create a function context for cross-call persistence */
        funcctx = SRF_FIRSTCALL_INIT();
 
        fctx = MemoryContextAlloc(funcctx->multi_call_memory_ctx,
                                  sizeof(int));
        funcctx->user_fctx = fctx;
 
        fctx[0] = 0;
    }
 
    /* stuff done on every call of the function */
    funcctx = SRF_PERCALL_SETUP();
    fctx = funcctx->user_fctx;
 
    fctx[0] += 1;
 
    /*
     * We recheck pgstat_fetch_stat_numbackends() each time through, just in
     * case the local status data has been refreshed since we started.  It's
     * plenty cheap enough if not.  If a refresh does happen, we'll likely
     * miss or duplicate some backend IDs, but we're content not to crash.
     * (Refreshing midway through such a query would be problematic usage
     * anyway, since the backend IDs we've already returned might no longer
     * refer to extant sessions.)
     */
    if (fctx[0] <= pgstat_fetch_stat_numbackends())
    {
        /* do when there is more left to send */
        LocalPgBackendStatus *local_beentry = pgstat_get_local_beentry_by_index(fctx[0]);
 
        SRF_RETURN_NEXT(funcctx, Int32GetDatum(local_beentry->proc_number));
    }
    else
    {
        /* do when there is no more left */
        SRF_RETURN_DONE(funcctx);
    }
}
 
/*
 * Returns command progress information for the named command.
 */
Datum
pg_stat_get_progress_info(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_PROGRESS_COLS   PGSTAT_NUM_PROGRESS_PARAM + 3
    int         num_backends = pgstat_fetch_stat_numbackends();
    int         curr_backend;
    char       *cmd = text_to_cstring(PG_GETARG_TEXT_PP(0));
    ProgressCommandType cmdtype;
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 
    /* Translate command name into command type code. */
    if (pg_strcasecmp(cmd, "VACUUM") == 0)
        cmdtype = PROGRESS_COMMAND_VACUUM;
    else if (pg_strcasecmp(cmd, "ANALYZE") == 0)
        cmdtype = PROGRESS_COMMAND_ANALYZE;
    else if (pg_strcasecmp(cmd, "CLUSTER") == 0)
        cmdtype = PROGRESS_COMMAND_CLUSTER;
    else if (pg_strcasecmp(cmd, "CREATE INDEX") == 0)
        cmdtype = PROGRESS_COMMAND_CREATE_INDEX;
    else if (pg_strcasecmp(cmd, "BASEBACKUP") == 0)
        cmdtype = PROGRESS_COMMAND_BASEBACKUP;
    else if (pg_strcasecmp(cmd, "COPY") == 0)
        cmdtype = PROGRESS_COMMAND_COPY;
    else
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("invalid command name: \"%s\"", cmd)));
 
    InitMaterializedSRF(fcinfo, 0);
 
    /* 1-based index */
    for (curr_backend = 1; curr_backend <= num_backends; curr_backend++)
    {
        LocalPgBackendStatus *local_beentry;
        PgBackendStatus *beentry;
        Datum       values[PG_STAT_GET_PROGRESS_COLS] = {0};
        bool        nulls[PG_STAT_GET_PROGRESS_COLS] = {0};
        int         i;
 
        local_beentry = pgstat_get_local_beentry_by_index(curr_backend);
        beentry = &local_beentry->backendStatus;
 
        /*
         * Report values for only those backends which are running the given
         * command.
         */
        if (beentry->st_progress_command != cmdtype)
            continue;
 
        /* Value available to all callers */
        values[0] = Int32GetDatum(beentry->st_procpid);
        values[1] = ObjectIdGetDatum(beentry->st_databaseid);
 
        /* show rest of the values including relid only to role members */
        if (HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        {
            values[2] = ObjectIdGetDatum(beentry->st_progress_command_target);
            for (i = 0; i < PGSTAT_NUM_PROGRESS_PARAM; i++)
                values[i + 3] = Int64GetDatum(beentry->st_progress_param[i]);
        }
        else
        {
            nulls[2] = true;
            for (i = 0; i < PGSTAT_NUM_PROGRESS_PARAM; i++)
                nulls[i + 3] = true;
        }
 
        tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
    }
 
    return (Datum) 0;
}
 
/*
 * Returns activity of PG backends.
 */
Datum
pg_stat_get_activity(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_ACTIVITY_COLS   31
    int         num_backends = pgstat_fetch_stat_numbackends();
    int         curr_backend;
    int         pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0);
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 
    InitMaterializedSRF(fcinfo, 0);
 
    /* 1-based index */
    for (curr_backend = 1; curr_backend <= num_backends; curr_backend++)
    {
        /* for each row */
        Datum       values[PG_STAT_GET_ACTIVITY_COLS] = {0};
        bool        nulls[PG_STAT_GET_ACTIVITY_COLS] = {0};
        LocalPgBackendStatus *local_beentry;
        PgBackendStatus *beentry;
        PGPROC     *proc;
        const char *wait_event_type = NULL;
        const char *wait_event = NULL;
 
        /* Get the next one in the list */
        local_beentry = pgstat_get_local_beentry_by_index(curr_backend);
        beentry = &local_beentry->backendStatus;
 
        /* If looking for specific PID, ignore all the others */
        if (pid != -1 && beentry->st_procpid != pid)
            continue;
 
        /* Values available to all callers */
        if (beentry->st_databaseid != InvalidOid)
            values[0] = ObjectIdGetDatum(beentry->st_databaseid);
        else
            nulls[0] = true;
 
        values[1] = Int32GetDatum(beentry->st_procpid);
 
        if (beentry->st_userid != InvalidOid)
            values[2] = ObjectIdGetDatum(beentry->st_userid);
        else
            nulls[2] = true;
 
        if (beentry->st_appname)
            values[3] = CStringGetTextDatum(beentry->st_appname);
        else
            nulls[3] = true;
 
        if (TransactionIdIsValid(local_beentry->backend_xid))
            values[15] = TransactionIdGetDatum(local_beentry->backend_xid);
        else
            nulls[15] = true;
 
        if (TransactionIdIsValid(local_beentry->backend_xmin))
            values[16] = TransactionIdGetDatum(local_beentry->backend_xmin);
        else
            nulls[16] = true;
 
        /* Values only available to role member or pg_read_all_stats */
        if (HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        {
            char       *clipped_activity;
 
            switch (beentry->st_state)
            {
                case STATE_IDLE:
                    values[4] = CStringGetTextDatum("idle");
                    break;
                case STATE_RUNNING:
                    values[4] = CStringGetTextDatum("active");
                    break;
                case STATE_IDLEINTRANSACTION:
                    values[4] = CStringGetTextDatum("idle in transaction");
                    break;
                case STATE_FASTPATH:
                    values[4] = CStringGetTextDatum("fastpath function call");
                    break;
                case STATE_IDLEINTRANSACTION_ABORTED:
                    values[4] = CStringGetTextDatum("idle in transaction (aborted)");
                    break;
                case STATE_DISABLED:
                    values[4] = CStringGetTextDatum("disabled");
                    break;
                case STATE_UNDEFINED:
                    nulls[4] = true;
                    break;
            }
 
            clipped_activity = pgstat_clip_activity(beentry->st_activity_raw);
            values[5] = CStringGetTextDatum(clipped_activity);
            pfree(clipped_activity);
 
            /* leader_pid */
            nulls[29] = true;
 
            proc = BackendPidGetProc(beentry->st_procpid);
 
            if (proc == NULL && (beentry->st_backendType != B_BACKEND))
            {
                /*
                 * For an auxiliary process, retrieve process info from
                 * AuxiliaryProcs stored in shared-memory.
                 */
                proc = AuxiliaryPidGetProc(beentry->st_procpid);
            }
 
            /*
             * If a PGPROC entry was retrieved, display wait events and lock
             * group leader or apply leader information if any.  To avoid
             * extra overhead, no extra lock is being held, so there is no
             * guarantee of consistency across multiple rows.
             */
            if (proc != NULL)
            {
                uint32      raw_wait_event;
                PGPROC     *leader;
 
                raw_wait_event = UINT32_ACCESS_ONCE(proc->wait_event_info);
                wait_event_type = pgstat_get_wait_event_type(raw_wait_event);
                wait_event = pgstat_get_wait_event(raw_wait_event);
 
                leader = proc->lockGroupLeader;
 
                /*
                 * Show the leader only for active parallel workers.  This
                 * leaves the field as NULL for the leader of a parallel group
                 * or the leader of parallel apply workers.
                 */
                if (leader && leader->pid != beentry->st_procpid)
                {
                    values[29] = Int32GetDatum(leader->pid);
                    nulls[29] = false;
                }
                else if (beentry->st_backendType == B_BG_WORKER)
                {
                    int         leader_pid = GetLeaderApplyWorkerPid(beentry->st_procpid);
 
                    if (leader_pid != InvalidPid)
                    {
                        values[29] = Int32GetDatum(leader_pid);
                        nulls[29] = false;
                    }
                }
            }
 
            if (wait_event_type)
                values[6] = CStringGetTextDatum(wait_event_type);
            else
                nulls[6] = true;
 
            if (wait_event)
                values[7] = CStringGetTextDatum(wait_event);
            else
                nulls[7] = true;
 
            /*
             * Don't expose transaction time for walsenders; it confuses
             * monitoring, particularly because we don't keep the time up-to-
             * date.
             */
            if (beentry->st_xact_start_timestamp != 0 &&
                beentry->st_backendType != B_WAL_SENDER)
                values[8] = TimestampTzGetDatum(beentry->st_xact_start_timestamp);
            else
                nulls[8] = true;
 
            if (beentry->st_activity_start_timestamp != 0)
                values[9] = TimestampTzGetDatum(beentry->st_activity_start_timestamp);
            else
                nulls[9] = true;
 
            if (beentry->st_proc_start_timestamp != 0)
                values[10] = TimestampTzGetDatum(beentry->st_proc_start_timestamp);
            else
                nulls[10] = true;
 
            if (beentry->st_state_start_timestamp != 0)
                values[11] = TimestampTzGetDatum(beentry->st_state_start_timestamp);
            else
                nulls[11] = true;
 
            /* A zeroed client addr means we don't know */
            if (pg_memory_is_all_zeros(&beentry->st_clientaddr,
                                       sizeof(beentry->st_clientaddr)))
            {
                nulls[12] = true;
                nulls[13] = true;
                nulls[14] = true;
            }
            else
            {
                if (beentry->st_clientaddr.addr.ss_family == AF_INET ||
                    beentry->st_clientaddr.addr.ss_family == AF_INET6)
                {
                    char        remote_host[NI_MAXHOST];
                    char        remote_port[NI_MAXSERV];
                    int         ret;
 
                    remote_host[0] = '\0';
                    remote_port[0] = '\0';
                    ret = pg_getnameinfo_all(&beentry->st_clientaddr.addr,
                                             beentry->st_clientaddr.salen,
                                             remote_host, sizeof(remote_host),
                                             remote_port, sizeof(remote_port),
                                             NI_NUMERICHOST | NI_NUMERICSERV);
                    if (ret == 0)
                    {
                        clean_ipv6_addr(beentry->st_clientaddr.addr.ss_family, remote_host);
                        values[12] = DirectFunctionCall1(inet_in,
                                                         CStringGetDatum(remote_host));
                        if (beentry->st_clienthostname &&
                            beentry->st_clienthostname[0])
                            values[13] = CStringGetTextDatum(beentry->st_clienthostname);
                        else
                            nulls[13] = true;
                        values[14] = Int32GetDatum(atoi(remote_port));
                    }
                    else
                    {
                        nulls[12] = true;
                        nulls[13] = true;
                        nulls[14] = true;
                    }
                }
                else if (beentry->st_clientaddr.addr.ss_family == AF_UNIX)
                {
                    /*
                     * Unix sockets always reports NULL for host and -1 for
                     * port, so it's possible to tell the difference to
                     * connections we have no permissions to view, or with
                     * errors.
                     */
                    nulls[12] = true;
                    nulls[13] = true;
                    values[14] = Int32GetDatum(-1);
                }
                else
                {
                    /* Unknown address type, should never happen */
                    nulls[12] = true;
                    nulls[13] = true;
                    nulls[14] = true;
                }
            }
            /* Add backend type */
            if (beentry->st_backendType == B_BG_WORKER)
            {
                const char *bgw_type;
 
                bgw_type = GetBackgroundWorkerTypeByPid(beentry->st_procpid);
                if (bgw_type)
                    values[17] = CStringGetTextDatum(bgw_type);
                else
                    nulls[17] = true;
            }
            else
                values[17] =
                    CStringGetTextDatum(GetBackendTypeDesc(beentry->st_backendType));
 
            /* SSL information */
            if (beentry->st_ssl)
            {
                values[18] = BoolGetDatum(true);    /* ssl */
                values[19] = CStringGetTextDatum(beentry->st_sslstatus->ssl_version);
                values[20] = CStringGetTextDatum(beentry->st_sslstatus->ssl_cipher);
                values[21] = Int32GetDatum(beentry->st_sslstatus->ssl_bits);
 
                if (beentry->st_sslstatus->ssl_client_dn[0])
                    values[22] = CStringGetTextDatum(beentry->st_sslstatus->ssl_client_dn);
                else
                    nulls[22] = true;
 
                if (beentry->st_sslstatus->ssl_client_serial[0])
                    values[23] = DirectFunctionCall3(numeric_in,
                                                     CStringGetDatum(beentry->st_sslstatus->ssl_client_serial),
                                                     ObjectIdGetDatum(InvalidOid),
                                                     Int32GetDatum(-1));
                else
                    nulls[23] = true;
 
                if (beentry->st_sslstatus->ssl_issuer_dn[0])
                    values[24] = CStringGetTextDatum(beentry->st_sslstatus->ssl_issuer_dn);
                else
                    nulls[24] = true;
            }
            else
            {
                values[18] = BoolGetDatum(false);   /* ssl */
                nulls[19] = nulls[20] = nulls[21] = nulls[22] = nulls[23] = nulls[24] = true;
            }
 
            /* GSSAPI information */
            if (beentry->st_gss)
            {
                values[25] = BoolGetDatum(beentry->st_gssstatus->gss_auth); /* gss_auth */
                values[26] = CStringGetTextDatum(beentry->st_gssstatus->gss_princ);
                values[27] = BoolGetDatum(beentry->st_gssstatus->gss_enc);  /* GSS Encryption in use */
                values[28] = BoolGetDatum(beentry->st_gssstatus->gss_delegation);   /* GSS credentials
                                                                                     * delegated */
            }
            else
            {
                values[25] = BoolGetDatum(false);   /* gss_auth */
                nulls[26] = true;   /* No GSS principal */
                values[27] = BoolGetDatum(false);   /* GSS Encryption not in
                                                     * use */
                values[28] = BoolGetDatum(false);   /* GSS credentials not
                                                     * delegated */
            }
            if (beentry->st_query_id == 0)
                nulls[30] = true;
            else
                values[30] = UInt64GetDatum(beentry->st_query_id);
        }
        else
        {
            /* No permissions to view data about this session */
            values[5] = CStringGetTextDatum("<insufficient privilege>");
            nulls[4] = true;
            nulls[6] = true;
            nulls[7] = true;
            nulls[8] = true;
            nulls[9] = true;
            nulls[10] = true;
            nulls[11] = true;
            nulls[12] = true;
            nulls[13] = true;
            nulls[14] = true;
            nulls[17] = true;
            nulls[18] = true;
            nulls[19] = true;
            nulls[20] = true;
            nulls[21] = true;
            nulls[22] = true;
            nulls[23] = true;
            nulls[24] = true;
            nulls[25] = true;
            nulls[26] = true;
            nulls[27] = true;
            nulls[28] = true;
            nulls[29] = true;
            nulls[30] = true;
        }
 
        tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 
        /* If only a single backend was requested, and we found it, break. */
        if (pid != -1)
            break;
    }
 
    return (Datum) 0;
}
 
 
Datum
pg_backend_pid(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT32(MyProcPid);
}
 
 
Datum
pg_stat_get_backend_pid(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        PG_RETURN_NULL();
 
    PG_RETURN_INT32(beentry->st_procpid);
}
 
 
Datum
pg_stat_get_backend_dbid(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        PG_RETURN_NULL();
 
    PG_RETURN_OID(beentry->st_databaseid);
}
 
 
Datum
pg_stat_get_backend_userid(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        PG_RETURN_NULL();
 
    PG_RETURN_OID(beentry->st_userid);
}
 
Datum
pg_stat_get_backend_subxact(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_SUBXACT_COLS    2
    TupleDesc   tupdesc;
    Datum       values[PG_STAT_GET_SUBXACT_COLS] = {0};
    bool        nulls[PG_STAT_GET_SUBXACT_COLS] = {0};
    int32       procNumber = PG_GETARG_INT32(0);
    LocalPgBackendStatus *local_beentry;
 
    /* Initialise attributes information in the tuple descriptor */
    tupdesc = CreateTemplateTupleDesc(PG_STAT_GET_SUBXACT_COLS);
    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "subxact_count",
                       INT4OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 2, "subxact_overflow",
                       BOOLOID, -1, 0);
 
    BlessTupleDesc(tupdesc);
 
    if ((local_beentry = pgstat_get_local_beentry_by_proc_number(procNumber)) != NULL)
    {
        /* Fill values and NULLs */
        values[0] = Int32GetDatum(local_beentry->backend_subxact_count);
        values[1] = BoolGetDatum(local_beentry->backend_subxact_overflowed);
    }
    else
    {
        nulls[0] = true;
        nulls[1] = true;
    }
 
    /* Returns the record as Datum */
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
 
Datum
pg_stat_get_backend_activity(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
    const char *activity;
    char       *clipped_activity;
    text       *ret;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        activity = "<backend information not available>";
    else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        activity = "<insufficient privilege>";
    else if (*(beentry->st_activity_raw) == '\0')
        activity = "<command string not enabled>";
    else
        activity = beentry->st_activity_raw;
 
    clipped_activity = pgstat_clip_activity(activity);
    ret = cstring_to_text(activity);
    pfree(clipped_activity);
 
    PG_RETURN_TEXT_P(ret);
}
 
Datum
pg_stat_get_backend_wait_event_type(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
    PGPROC     *proc;
    const char *wait_event_type = NULL;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        wait_event_type = "<backend information not available>";
    else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        wait_event_type = "<insufficient privilege>";
    else if ((proc = BackendPidGetProc(beentry->st_procpid)) != NULL)
        wait_event_type = pgstat_get_wait_event_type(proc->wait_event_info);
 
    if (!wait_event_type)
        PG_RETURN_NULL();
 
    PG_RETURN_TEXT_P(cstring_to_text(wait_event_type));
}
 
Datum
pg_stat_get_backend_wait_event(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
    PGPROC     *proc;
    const char *wait_event = NULL;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        wait_event = "<backend information not available>";
    else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        wait_event = "<insufficient privilege>";
    else if ((proc = BackendPidGetProc(beentry->st_procpid)) != NULL)
        wait_event = pgstat_get_wait_event(proc->wait_event_info);
 
    if (!wait_event)
        PG_RETURN_NULL();
 
    PG_RETURN_TEXT_P(cstring_to_text(wait_event));
}
 
 
Datum
pg_stat_get_backend_activity_start(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    TimestampTz result;
    PgBackendStatus *beentry;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        PG_RETURN_NULL();
 
    else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        PG_RETURN_NULL();
 
    result = beentry->st_activity_start_timestamp;
 
    /*
     * No time recorded for start of current query -- this is the case if the
     * user hasn't enabled query-level stats collection.
     */
    if (result == 0)
        PG_RETURN_NULL();
 
    PG_RETURN_TIMESTAMPTZ(result);
}
 
 
Datum
pg_stat_get_backend_xact_start(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    TimestampTz result;
    PgBackendStatus *beentry;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        PG_RETURN_NULL();
 
    else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        PG_RETURN_NULL();
 
    result = beentry->st_xact_start_timestamp;
 
    if (result == 0)            /* not in a transaction */
        PG_RETURN_NULL();
 
    PG_RETURN_TIMESTAMPTZ(result);
}
 
 
Datum
pg_stat_get_backend_start(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    TimestampTz result;
    PgBackendStatus *beentry;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        PG_RETURN_NULL();
 
    else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        PG_RETURN_NULL();
 
    result = beentry->st_proc_start_timestamp;
 
    if (result == 0)            /* probably can't happen? */
        PG_RETURN_NULL();
 
    PG_RETURN_TIMESTAMPTZ(result);
}
 
 
Datum
pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
    char        remote_host[NI_MAXHOST];
    int         ret;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        PG_RETURN_NULL();
 
    else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        PG_RETURN_NULL();
 
    /* A zeroed client addr means we don't know */
    if (pg_memory_is_all_zeros(&beentry->st_clientaddr,
                               sizeof(beentry->st_clientaddr)))
        PG_RETURN_NULL();
 
    switch (beentry->st_clientaddr.addr.ss_family)
    {
        case AF_INET:
        case AF_INET6:
            break;
        default:
            PG_RETURN_NULL();
    }
 
    remote_host[0] = '\0';
    ret = pg_getnameinfo_all(&beentry->st_clientaddr.addr,
                             beentry->st_clientaddr.salen,
                             remote_host, sizeof(remote_host),
                             NULL, 0,
                             NI_NUMERICHOST | NI_NUMERICSERV);
    if (ret != 0)
        PG_RETURN_NULL();
 
    clean_ipv6_addr(beentry->st_clientaddr.addr.ss_family, remote_host);
 
    PG_RETURN_DATUM(DirectFunctionCall1(inet_in,
                                        CStringGetDatum(remote_host)));
}
 
Datum
pg_stat_get_backend_client_port(PG_FUNCTION_ARGS)
{
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
    char        remote_port[NI_MAXSERV];
    int         ret;
 
    if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL)
        PG_RETURN_NULL();
 
    else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        PG_RETURN_NULL();
 
    /* A zeroed client addr means we don't know */
    if (pg_memory_is_all_zeros(&beentry->st_clientaddr,
                               sizeof(beentry->st_clientaddr)))
        PG_RETURN_NULL();
 
    switch (beentry->st_clientaddr.addr.ss_family)
    {
        case AF_INET:
        case AF_INET6:
            break;
        case AF_UNIX:
            PG_RETURN_INT32(-1);
        default:
            PG_RETURN_NULL();
    }
 
    remote_port[0] = '\0';
    ret = pg_getnameinfo_all(&beentry->st_clientaddr.addr,
                             beentry->st_clientaddr.salen,
                             NULL, 0,
                             remote_port, sizeof(remote_port),
                             NI_NUMERICHOST | NI_NUMERICSERV);
    if (ret != 0)
        PG_RETURN_NULL();
 
    PG_RETURN_DATUM(DirectFunctionCall1(int4in,
                                        CStringGetDatum(remote_port)));
}
 
 
Datum
pg_stat_get_db_numbackends(PG_FUNCTION_ARGS)
{
    Oid         dbid = PG_GETARG_OID(0);
    int32       result;
    int         tot_backends = pgstat_fetch_stat_numbackends();
    int         idx;
 
    result = 0;
    for (idx = 1; idx <= tot_backends; idx++)
    {
        LocalPgBackendStatus *local_beentry = pgstat_get_local_beentry_by_index(idx);
 
        if (local_beentry->backendStatus.st_databaseid == dbid)
            result++;
    }
 
    PG_RETURN_INT32(result);
}
 
 
#define PG_STAT_GET_DBENTRY_INT64(stat)                         \
Datum                                                           \
CppConcat(pg_stat_get_db_,stat)(PG_FUNCTION_ARGS)               \
{                                                               \
    Oid         dbid = PG_GETARG_OID(0);                        \
    int64       result;                                         \
    PgStat_StatDBEntry *dbentry;                                \
                                                                \
    if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)    \
        result = 0;                                             \
    else                                                        \
        result = (int64) (dbentry->stat);                       \
                                                                \
    PG_RETURN_INT64(result);                                    \
}
 
/* pg_stat_get_db_blocks_fetched */
PG_STAT_GET_DBENTRY_INT64(blocks_fetched)
 
/* pg_stat_get_db_blocks_hit */
PG_STAT_GET_DBENTRY_INT64(blocks_hit)
 
/* pg_stat_get_db_conflict_bufferpin */
PG_STAT_GET_DBENTRY_INT64(conflict_bufferpin)
 
/* pg_stat_get_db_conflict_lock */
PG_STAT_GET_DBENTRY_INT64(conflict_lock)
 
/* pg_stat_get_db_conflict_snapshot */
PG_STAT_GET_DBENTRY_INT64(conflict_snapshot)
 
/* pg_stat_get_db_conflict_startup_deadlock */
PG_STAT_GET_DBENTRY_INT64(conflict_startup_deadlock)
 
/* pg_stat_get_db_conflict_tablespace */
PG_STAT_GET_DBENTRY_INT64(conflict_tablespace)
 
/* pg_stat_get_db_deadlocks */
PG_STAT_GET_DBENTRY_INT64(deadlocks)
 
/* pg_stat_get_db_sessions */
PG_STAT_GET_DBENTRY_INT64(sessions)
 
/* pg_stat_get_db_sessions_abandoned */
PG_STAT_GET_DBENTRY_INT64(sessions_abandoned)
 
/* pg_stat_get_db_sessions_fatal */
PG_STAT_GET_DBENTRY_INT64(sessions_fatal)
 
/* pg_stat_get_db_sessions_killed */
PG_STAT_GET_DBENTRY_INT64(sessions_killed)
 
/* pg_stat_get_db_parallel_workers_to_launch */
PG_STAT_GET_DBENTRY_INT64(parallel_workers_to_launch)
 
/* pg_stat_get_db_parallel_workers_launched */
PG_STAT_GET_DBENTRY_INT64(parallel_workers_launched)
 
/* pg_stat_get_db_temp_bytes */
PG_STAT_GET_DBENTRY_INT64(temp_bytes)
 
/* pg_stat_get_db_temp_files */
PG_STAT_GET_DBENTRY_INT64(temp_files)
 
/* pg_stat_get_db_tuples_deleted */
PG_STAT_GET_DBENTRY_INT64(tuples_deleted)
 
/* pg_stat_get_db_tuples_fetched */
PG_STAT_GET_DBENTRY_INT64(tuples_fetched)
 
/* pg_stat_get_db_tuples_inserted */
PG_STAT_GET_DBENTRY_INT64(tuples_inserted)
 
/* pg_stat_get_db_tuples_returned */
PG_STAT_GET_DBENTRY_INT64(tuples_returned)
 
/* pg_stat_get_db_tuples_updated */
PG_STAT_GET_DBENTRY_INT64(tuples_updated)
 
/* pg_stat_get_db_xact_commit */
PG_STAT_GET_DBENTRY_INT64(xact_commit)
 
/* pg_stat_get_db_xact_rollback */
PG_STAT_GET_DBENTRY_INT64(xact_rollback)
 
/* pg_stat_get_db_conflict_logicalslot */
PG_STAT_GET_DBENTRY_INT64(conflict_logicalslot)
 
Datum
pg_stat_get_db_stat_reset_time(PG_FUNCTION_ARGS)
{
    Oid         dbid = PG_GETARG_OID(0);
    TimestampTz result;
    PgStat_StatDBEntry *dbentry;
 
    if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
        result = 0;
    else
        result = dbentry->stat_reset_timestamp;
 
    if (result == 0)
        PG_RETURN_NULL();
    else
        PG_RETURN_TIMESTAMPTZ(result);
}
 
 
Datum
pg_stat_get_db_conflict_all(PG_FUNCTION_ARGS)
{
    Oid         dbid = PG_GETARG_OID(0);
    int64       result;
    PgStat_StatDBEntry *dbentry;
 
    if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
        result = 0;
    else
        result = (int64) (dbentry->conflict_tablespace +
                          dbentry->conflict_lock +
                          dbentry->conflict_snapshot +
                          dbentry->conflict_logicalslot +
                          dbentry->conflict_bufferpin +
                          dbentry->conflict_startup_deadlock);
 
    PG_RETURN_INT64(result);
}
 
Datum
pg_stat_get_db_checksum_failures(PG_FUNCTION_ARGS)
{
    Oid         dbid = PG_GETARG_OID(0);
    int64       result;
    PgStat_StatDBEntry *dbentry;
 
    if (!DataChecksumsEnabled())
        PG_RETURN_NULL();
 
    if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
        result = 0;
    else
        result = (int64) (dbentry->checksum_failures);
 
    PG_RETURN_INT64(result);
}
 
Datum
pg_stat_get_db_checksum_last_failure(PG_FUNCTION_ARGS)
{
    Oid         dbid = PG_GETARG_OID(0);
    TimestampTz result;
    PgStat_StatDBEntry *dbentry;
 
    if (!DataChecksumsEnabled())
        PG_RETURN_NULL();
 
    if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
        result = 0;
    else
        result = dbentry->last_checksum_failure;
 
    if (result == 0)
        PG_RETURN_NULL();
    else
        PG_RETURN_TIMESTAMPTZ(result);
}
 
/* convert counter from microsec to millisec for display */
#define PG_STAT_GET_DBENTRY_FLOAT8_MS(stat)                     \
Datum                                                           \
CppConcat(pg_stat_get_db_,stat)(PG_FUNCTION_ARGS)               \
{                                                               \
    Oid         dbid = PG_GETARG_OID(0);                        \
    double      result;                                         \
    PgStat_StatDBEntry *dbentry;                                \
                                                                \
    if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)    \
        result = 0;                                             \
    else                                                        \
        result = ((double) dbentry->stat) / 1000.0;             \
                                                                \
    PG_RETURN_FLOAT8(result);                                   \
}
 
/* pg_stat_get_db_active_time */
PG_STAT_GET_DBENTRY_FLOAT8_MS(active_time)
 
/* pg_stat_get_db_blk_read_time */
PG_STAT_GET_DBENTRY_FLOAT8_MS(blk_read_time)
 
/* pg_stat_get_db_blk_write_time */
PG_STAT_GET_DBENTRY_FLOAT8_MS(blk_write_time)
 
/* pg_stat_get_db_idle_in_transaction_time */
PG_STAT_GET_DBENTRY_FLOAT8_MS(idle_in_transaction_time)
 
/* pg_stat_get_db_session_time */
PG_STAT_GET_DBENTRY_FLOAT8_MS(session_time)
 
Datum
pg_stat_get_checkpointer_num_timed(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->num_timed);
}
 
Datum
pg_stat_get_checkpointer_num_requested(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->num_requested);
}
 
Datum
pg_stat_get_checkpointer_num_performed(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->num_performed);
}
 
Datum
pg_stat_get_checkpointer_restartpoints_timed(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->restartpoints_timed);
}
 
Datum
pg_stat_get_checkpointer_restartpoints_requested(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->restartpoints_requested);
}
 
Datum
pg_stat_get_checkpointer_restartpoints_performed(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->restartpoints_performed);
}
 
Datum
pg_stat_get_checkpointer_buffers_written(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->buffers_written);
}
 
Datum
pg_stat_get_checkpointer_slru_written(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->slru_written);
}
 
Datum
pg_stat_get_bgwriter_buf_written_clean(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_bgwriter()->buf_written_clean);
}
 
Datum
pg_stat_get_bgwriter_maxwritten_clean(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_bgwriter()->maxwritten_clean);
}
 
Datum
pg_stat_get_checkpointer_write_time(PG_FUNCTION_ARGS)
{
    /* time is already in msec, just convert to double for presentation */
    PG_RETURN_FLOAT8((double)
                     pgstat_fetch_stat_checkpointer()->write_time);
}
 
Datum
pg_stat_get_checkpointer_sync_time(PG_FUNCTION_ARGS)
{
    /* time is already in msec, just convert to double for presentation */
    PG_RETURN_FLOAT8((double)
                     pgstat_fetch_stat_checkpointer()->sync_time);
}
 
Datum
pg_stat_get_checkpointer_stat_reset_time(PG_FUNCTION_ARGS)
{
    PG_RETURN_TIMESTAMPTZ(pgstat_fetch_stat_checkpointer()->stat_reset_timestamp);
}
 
Datum
pg_stat_get_bgwriter_stat_reset_time(PG_FUNCTION_ARGS)
{
    PG_RETURN_TIMESTAMPTZ(pgstat_fetch_stat_bgwriter()->stat_reset_timestamp);
}
 
Datum
pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_stat_bgwriter()->buf_alloc);
}
 
/*
* When adding a new column to the pg_stat_io view and the
* pg_stat_get_backend_io() function, add a new enum value here above
* IO_NUM_COLUMNS.
*/
typedef enum io_stat_col
{
    IO_COL_INVALID = -1,
    IO_COL_BACKEND_TYPE,
    IO_COL_OBJECT,
    IO_COL_CONTEXT,
    IO_COL_READS,
    IO_COL_READ_BYTES,
    IO_COL_READ_TIME,
    IO_COL_WRITES,
    IO_COL_WRITE_BYTES,
    IO_COL_WRITE_TIME,
    IO_COL_WRITEBACKS,
    IO_COL_WRITEBACK_TIME,
    IO_COL_EXTENDS,
    IO_COL_EXTEND_BYTES,
    IO_COL_EXTEND_TIME,
    IO_COL_HITS,
    IO_COL_EVICTIONS,
    IO_COL_REUSES,
    IO_COL_FSYNCS,
    IO_COL_FSYNC_TIME,
    IO_COL_RESET_TIME,
    IO_NUM_COLUMNS,
} io_stat_col;
 
/*
 * When adding a new IOOp, add a new io_stat_col and add a case to this
 * function returning the corresponding io_stat_col.
 */
static io_stat_col
pgstat_get_io_op_index(IOOp io_op)
{
    switch (io_op)
    {
        case IOOP_EVICT:
            return IO_COL_EVICTIONS;
        case IOOP_EXTEND:
            return IO_COL_EXTENDS;
        case IOOP_FSYNC:
            return IO_COL_FSYNCS;
        case IOOP_HIT:
            return IO_COL_HITS;
        case IOOP_READ:
            return IO_COL_READS;
        case IOOP_REUSE:
            return IO_COL_REUSES;
        case IOOP_WRITE:
            return IO_COL_WRITES;
        case IOOP_WRITEBACK:
            return IO_COL_WRITEBACKS;
    }
 
    elog(ERROR, "unrecognized IOOp value: %d", io_op);
    pg_unreachable();
}
 
/*
 * Get the number of the column containing IO bytes for the specified IOOp.
 * If an IOOp is not tracked in bytes, IO_COL_INVALID is returned.
 */
static io_stat_col
pgstat_get_io_byte_index(IOOp io_op)
{
    switch (io_op)
    {
        case IOOP_EXTEND:
            return IO_COL_EXTEND_BYTES;
        case IOOP_READ:
            return IO_COL_READ_BYTES;
        case IOOP_WRITE:
            return IO_COL_WRITE_BYTES;
        case IOOP_EVICT:
        case IOOP_FSYNC:
        case IOOP_HIT:
        case IOOP_REUSE:
        case IOOP_WRITEBACK:
            return IO_COL_INVALID;
    }
 
    elog(ERROR, "unrecognized IOOp value: %d", io_op);
    pg_unreachable();
}
 
/*
 * Get the number of the column containing IO times for the specified IOOp.
 * If an op has no associated time, IO_COL_INVALID is returned.
 */
static io_stat_col
pgstat_get_io_time_index(IOOp io_op)
{
    switch (io_op)
    {
        case IOOP_READ:
            return IO_COL_READ_TIME;
        case IOOP_WRITE:
            return IO_COL_WRITE_TIME;
        case IOOP_WRITEBACK:
            return IO_COL_WRITEBACK_TIME;
        case IOOP_EXTEND:
            return IO_COL_EXTEND_TIME;
        case IOOP_FSYNC:
            return IO_COL_FSYNC_TIME;
        case IOOP_EVICT:
        case IOOP_HIT:
        case IOOP_REUSE:
            return IO_COL_INVALID;
    }
 
    elog(ERROR, "unrecognized IOOp value: %d", io_op);
    pg_unreachable();
}
 
static inline double
pg_stat_us_to_ms(PgStat_Counter val_ms)
{
    return val_ms * (double) 0.001;
}
 
/*
 * pg_stat_io_build_tuples
 *
 * Helper routine for pg_stat_get_io() and pg_stat_get_backend_io()
 * filling a result tuplestore with one tuple for each object and each
 * context supported by the caller, based on the contents of bktype_stats.
 */
static void
pg_stat_io_build_tuples(ReturnSetInfo *rsinfo,
                        PgStat_BktypeIO *bktype_stats,
                        BackendType bktype,
                        TimestampTz stat_reset_timestamp)
{
    Datum       bktype_desc = CStringGetTextDatum(GetBackendTypeDesc(bktype));
 
    for (int io_obj = 0; io_obj < IOOBJECT_NUM_TYPES; io_obj++)
    {
        const char *obj_name = pgstat_get_io_object_name(io_obj);
 
        for (int io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
        {
            const char *context_name = pgstat_get_io_context_name(io_context);
 
            Datum       values[IO_NUM_COLUMNS] = {0};
            bool        nulls[IO_NUM_COLUMNS] = {0};
 
            /*
             * Some combinations of BackendType, IOObject, and IOContext are
             * not valid for any type of IOOp. In such cases, omit the entire
             * row from the view.
             */
            if (!pgstat_tracks_io_object(bktype, io_obj, io_context))
                continue;
 
            values[IO_COL_BACKEND_TYPE] = bktype_desc;
            values[IO_COL_CONTEXT] = CStringGetTextDatum(context_name);
            values[IO_COL_OBJECT] = CStringGetTextDatum(obj_name);
            if (stat_reset_timestamp != 0)
                values[IO_COL_RESET_TIME] = TimestampTzGetDatum(stat_reset_timestamp);
            else
                nulls[IO_COL_RESET_TIME] = true;
 
            for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
            {
                int         op_idx = pgstat_get_io_op_index(io_op);
                int         time_idx = pgstat_get_io_time_index(io_op);
                int         byte_idx = pgstat_get_io_byte_index(io_op);
 
                /*
                 * Some combinations of BackendType and IOOp, of IOContext and
                 * IOOp, and of IOObject and IOOp are not tracked. Set these
                 * cells in the view NULL.
                 */
                if (pgstat_tracks_io_op(bktype, io_obj, io_context, io_op))
                {
                    PgStat_Counter count =
                        bktype_stats->counts[io_obj][io_context][io_op];
 
                    values[op_idx] = Int64GetDatum(count);
                }
                else
                    nulls[op_idx] = true;
 
                if (!nulls[op_idx])
                {
                    /* not every operation is timed */
                    if (time_idx != IO_COL_INVALID)
                    {
                        PgStat_Counter time =
                            bktype_stats->times[io_obj][io_context][io_op];
 
                        values[time_idx] = Float8GetDatum(pg_stat_us_to_ms(time));
                    }
 
                    /* not every IO is tracked in bytes */
                    if (byte_idx != IO_COL_INVALID)
                    {
                        char        buf[256];
                        PgStat_Counter byte =
                            bktype_stats->bytes[io_obj][io_context][io_op];
 
                        /* Convert to numeric */
                        snprintf(buf, sizeof buf, UINT64_FORMAT, byte);
                        values[byte_idx] = DirectFunctionCall3(numeric_in,
                                                               CStringGetDatum(buf),
                                                               ObjectIdGetDatum(0),
                                                               Int32GetDatum(-1));
                    }
                }
                else
                {
                    if (time_idx != IO_COL_INVALID)
                        nulls[time_idx] = true;
                    if (byte_idx != IO_COL_INVALID)
                        nulls[byte_idx] = true;
                }
            }
 
            tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
                                 values, nulls);
        }
    }
}
 
Datum
pg_stat_get_io(PG_FUNCTION_ARGS)
{
    ReturnSetInfo *rsinfo;
    PgStat_IO  *backends_io_stats;
 
    InitMaterializedSRF(fcinfo, 0);
    rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 
    backends_io_stats = pgstat_fetch_stat_io();
 
    for (int bktype = 0; bktype < BACKEND_NUM_TYPES; bktype++)
    {
        PgStat_BktypeIO *bktype_stats = &backends_io_stats->stats[bktype];
 
        /*
         * In Assert builds, we can afford an extra loop through all of the
         * counters (in pg_stat_io_build_tuples()), checking that only
         * expected stats are non-zero, since it keeps the non-Assert code
         * cleaner.
         */
        Assert(pgstat_bktype_io_stats_valid(bktype_stats, bktype));
 
        /*
         * For those BackendTypes without IO Operation stats, skip
         * representing them in the view altogether.
         */
        if (!pgstat_tracks_io_bktype(bktype))
            continue;
 
        /* save tuples with data from this PgStat_BktypeIO */
        pg_stat_io_build_tuples(rsinfo, bktype_stats, bktype,
                                backends_io_stats->stat_reset_timestamp);
    }
 
    return (Datum) 0;
}
 
/*
 * Returns I/O statistics for a backend with given PID.
 */
Datum
pg_stat_get_backend_io(PG_FUNCTION_ARGS)
{
    ReturnSetInfo *rsinfo;
    BackendType bktype;
    int         pid;
    PGPROC     *proc;
    ProcNumber  procNumber;
    PgStat_Backend *backend_stats;
    PgStat_BktypeIO *bktype_stats;
    PgBackendStatus *beentry;
 
    InitMaterializedSRF(fcinfo, 0);
    rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 
    pid = PG_GETARG_INT32(0);
    proc = BackendPidGetProc(pid);
 
    /*
     * This could be an auxiliary process but these do not report backend
     * statistics due to pgstat_tracks_backend_bktype(), so there is no need
     * for an extra call to AuxiliaryPidGetProc().
     */
    if (!proc)
        return (Datum) 0;
 
    procNumber = GetNumberFromPGProc(proc);
 
    beentry = pgstat_get_beentry_by_proc_number(procNumber);
    if (!beentry)
        return (Datum) 0;
 
    backend_stats = pgstat_fetch_stat_backend(procNumber);
    if (!backend_stats)
        return (Datum) 0;
 
    bktype = beentry->st_backendType;
 
    /* if PID does not match, leave */
    if (beentry->st_procpid != pid)
        return (Datum) 0;
 
    /* backend may be gone, so recheck in case */
    if (bktype == B_INVALID)
        return (Datum) 0;
 
    bktype_stats = &backend_stats->io_stats;
 
    /*
     * In Assert builds, we can afford an extra loop through all of the
     * counters (in pg_stat_io_build_tuples()), checking that only expected
     * stats are non-zero, since it keeps the non-Assert code cleaner.
     */
    Assert(pgstat_bktype_io_stats_valid(bktype_stats, bktype));
 
    /* save tuples with data from this PgStat_BktypeIO */
    pg_stat_io_build_tuples(rsinfo, bktype_stats, bktype,
                            backend_stats->stat_reset_timestamp);
    return (Datum) 0;
}
 
/*
 * Returns statistics of WAL activity
 */
Datum
pg_stat_get_wal(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_WAL_COLS    9
    TupleDesc   tupdesc;
    Datum       values[PG_STAT_GET_WAL_COLS] = {0};
    bool        nulls[PG_STAT_GET_WAL_COLS] = {0};
    char        buf[256];
    PgStat_WalStats *wal_stats;
 
    /* Initialise attributes information in the tuple descriptor */
    tupdesc = CreateTemplateTupleDesc(PG_STAT_GET_WAL_COLS);
    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "wal_records",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 2, "wal_fpi",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 3, "wal_bytes",
                       NUMERICOID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 4, "wal_buffers_full",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 5, "wal_write",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 6, "wal_sync",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 7, "wal_write_time",
                       FLOAT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 8, "wal_sync_time",
                       FLOAT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 9, "stats_reset",
                       TIMESTAMPTZOID, -1, 0);
 
    BlessTupleDesc(tupdesc);
 
    /* Get statistics about WAL activity */
    wal_stats = pgstat_fetch_stat_wal();
 
    /* Fill values and NULLs */
    values[0] = Int64GetDatum(wal_stats->wal_records);
    values[1] = Int64GetDatum(wal_stats->wal_fpi);
 
    /* Convert to numeric. */
    snprintf(buf, sizeof buf, UINT64_FORMAT, wal_stats->wal_bytes);
    values[2] = DirectFunctionCall3(numeric_in,
                                    CStringGetDatum(buf),
                                    ObjectIdGetDatum(0),
                                    Int32GetDatum(-1));
 
    values[3] = Int64GetDatum(wal_stats->wal_buffers_full);
    values[4] = Int64GetDatum(wal_stats->wal_write);
    values[5] = Int64GetDatum(wal_stats->wal_sync);
 
    /* Convert counters from microsec to millisec for display */
    values[6] = Float8GetDatum(((double) wal_stats->wal_write_time) / 1000.0);
    values[7] = Float8GetDatum(((double) wal_stats->wal_sync_time) / 1000.0);
 
    values[8] = TimestampTzGetDatum(wal_stats->stat_reset_timestamp);
 
    /* Returns the record as Datum */
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
 
/*
 * Returns statistics of SLRU caches.
 */
Datum
pg_stat_get_slru(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_SLRU_COLS   9
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    int         i;
    PgStat_SLRUStats *stats;
 
    InitMaterializedSRF(fcinfo, 0);
 
    /* request SLRU stats from the cumulative stats system */
    stats = pgstat_fetch_slru();
 
    for (i = 0;; i++)
    {
        /* for each row */
        Datum       values[PG_STAT_GET_SLRU_COLS] = {0};
        bool        nulls[PG_STAT_GET_SLRU_COLS] = {0};
        PgStat_SLRUStats stat;
        const char *name;
 
        name = pgstat_get_slru_name(i);
 
        if (!name)
            break;
 
        stat = stats[i];
 
        values[0] = PointerGetDatum(cstring_to_text(name));
        values[1] = Int64GetDatum(stat.blocks_zeroed);
        values[2] = Int64GetDatum(stat.blocks_hit);
        values[3] = Int64GetDatum(stat.blocks_read);
        values[4] = Int64GetDatum(stat.blocks_written);
        values[5] = Int64GetDatum(stat.blocks_exists);
        values[6] = Int64GetDatum(stat.flush);
        values[7] = Int64GetDatum(stat.truncate);
        values[8] = TimestampTzGetDatum(stat.stat_reset_timestamp);
 
        tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
    }
 
    return (Datum) 0;
}
 
#define PG_STAT_GET_XACT_RELENTRY_INT64(stat)           \
Datum                                                   \
CppConcat(pg_stat_get_xact_,stat)(PG_FUNCTION_ARGS)     \
{                                                       \
    Oid         relid = PG_GETARG_OID(0);               \
    int64       result;                                 \
    PgStat_TableStatus *tabentry;                       \
                                                        \
    if ((tabentry = find_tabstat_entry(relid)) == NULL) \
        result = 0;                                     \
    else                                                \
        result = (int64) (tabentry->counts.stat);       \
                                                        \
    PG_RETURN_INT64(result);                            \
}
 
/* pg_stat_get_xact_numscans */
PG_STAT_GET_XACT_RELENTRY_INT64(numscans)
 
/* pg_stat_get_xact_tuples_returned */
PG_STAT_GET_XACT_RELENTRY_INT64(tuples_returned)
 
/* pg_stat_get_xact_tuples_fetched */
PG_STAT_GET_XACT_RELENTRY_INT64(tuples_fetched)
 
/* pg_stat_get_xact_tuples_hot_updated */
PG_STAT_GET_XACT_RELENTRY_INT64(tuples_hot_updated)
 
/* pg_stat_get_xact_tuples_newpage_updated */
PG_STAT_GET_XACT_RELENTRY_INT64(tuples_newpage_updated)
 
/* pg_stat_get_xact_blocks_fetched */
PG_STAT_GET_XACT_RELENTRY_INT64(blocks_fetched)
 
/* pg_stat_get_xact_blocks_hit */
PG_STAT_GET_XACT_RELENTRY_INT64(blocks_hit)
 
/* pg_stat_get_xact_tuples_inserted */
PG_STAT_GET_XACT_RELENTRY_INT64(tuples_inserted)
 
/* pg_stat_get_xact_tuples_updated */
PG_STAT_GET_XACT_RELENTRY_INT64(tuples_updated)
 
/* pg_stat_get_xact_tuples_deleted */
PG_STAT_GET_XACT_RELENTRY_INT64(tuples_deleted)
 
Datum
pg_stat_get_xact_function_calls(PG_FUNCTION_ARGS)
{
    Oid         funcid = PG_GETARG_OID(0);
    PgStat_FunctionCounts *funcentry;
 
    if ((funcentry = find_funcstat_entry(funcid)) == NULL)
        PG_RETURN_NULL();
    PG_RETURN_INT64(funcentry->numcalls);
}
 
#define PG_STAT_GET_XACT_FUNCENTRY_FLOAT8_MS(stat)              \
Datum                                                           \
CppConcat(pg_stat_get_xact_function_,stat)(PG_FUNCTION_ARGS)    \
{                                                               \
    Oid         funcid = PG_GETARG_OID(0);                      \
    PgStat_FunctionCounts *funcentry;                           \
                                                                \
    if ((funcentry = find_funcstat_entry(funcid)) == NULL)      \
        PG_RETURN_NULL();                                       \
    PG_RETURN_FLOAT8(INSTR_TIME_GET_MILLISEC(funcentry->stat)); \
}
 
/* pg_stat_get_xact_function_total_time */
PG_STAT_GET_XACT_FUNCENTRY_FLOAT8_MS(total_time)
 
/* pg_stat_get_xact_function_self_time */
PG_STAT_GET_XACT_FUNCENTRY_FLOAT8_MS(self_time)
 
/* Get the timestamp of the current statistics snapshot */
Datum
pg_stat_get_snapshot_timestamp(PG_FUNCTION_ARGS)
{
    bool        have_snapshot;
    TimestampTz ts;
 
    ts = pgstat_get_stat_snapshot_timestamp(&have_snapshot);
 
    if (!have_snapshot)
        PG_RETURN_NULL();
 
    PG_RETURN_TIMESTAMPTZ(ts);
}
 
/* Discard the active statistics snapshot */
Datum
pg_stat_clear_snapshot(PG_FUNCTION_ARGS)
{
    pgstat_clear_snapshot();
 
    PG_RETURN_VOID();
}
 
 
/* Force statistics to be reported at the next occasion */
Datum
pg_stat_force_next_flush(PG_FUNCTION_ARGS)
{
    pgstat_force_next_flush();
 
    PG_RETURN_VOID();
}
 
 
/* Reset all counters for the current database */
Datum
pg_stat_reset(PG_FUNCTION_ARGS)
{
    pgstat_reset_counters();
 
    PG_RETURN_VOID();
}
 
/*
 * Reset some shared cluster-wide counters
 *
 * When adding a new reset target, ideally the name should match that in
 * pgstat_kind_builtin_infos, if relevant.
 */
Datum
pg_stat_reset_shared(PG_FUNCTION_ARGS)
{
    char       *target = NULL;
 
    if (PG_ARGISNULL(0))
    {
        /* Reset all the statistics when nothing is specified */
        pgstat_reset_of_kind(PGSTAT_KIND_ARCHIVER);
        pgstat_reset_of_kind(PGSTAT_KIND_BGWRITER);
        pgstat_reset_of_kind(PGSTAT_KIND_CHECKPOINTER);
        pgstat_reset_of_kind(PGSTAT_KIND_IO);
        XLogPrefetchResetStats();
        pgstat_reset_of_kind(PGSTAT_KIND_SLRU);
        pgstat_reset_of_kind(PGSTAT_KIND_WAL);
 
        PG_RETURN_VOID();
    }
 
    target = text_to_cstring(PG_GETARG_TEXT_PP(0));
 
    if (strcmp(target, "archiver") == 0)
        pgstat_reset_of_kind(PGSTAT_KIND_ARCHIVER);
    else if (strcmp(target, "bgwriter") == 0)
        pgstat_reset_of_kind(PGSTAT_KIND_BGWRITER);
    else if (strcmp(target, "checkpointer") == 0)
        pgstat_reset_of_kind(PGSTAT_KIND_CHECKPOINTER);
    else if (strcmp(target, "io") == 0)
        pgstat_reset_of_kind(PGSTAT_KIND_IO);
    else if (strcmp(target, "recovery_prefetch") == 0)
        XLogPrefetchResetStats();
    else if (strcmp(target, "slru") == 0)
        pgstat_reset_of_kind(PGSTAT_KIND_SLRU);
    else if (strcmp(target, "wal") == 0)
        pgstat_reset_of_kind(PGSTAT_KIND_WAL);
    else
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("unrecognized reset target: \"%s\"", target),
                 errhint("Target must be \"archiver\", \"bgwriter\", \"checkpointer\", \"io\", \"recovery_prefetch\", \"slru\", or \"wal\".")));
 
    PG_RETURN_VOID();
}
 
/*
 * Reset a statistics for a single object, which may be of current
 * database or shared across all databases in the cluster.
 */
Datum
pg_stat_reset_single_table_counters(PG_FUNCTION_ARGS)
{
    Oid         taboid = PG_GETARG_OID(0);
    Oid         dboid = (IsSharedRelation(taboid) ? InvalidOid : MyDatabaseId);
 
    pgstat_reset(PGSTAT_KIND_RELATION, dboid, taboid);
 
    PG_RETURN_VOID();
}
 
Datum
pg_stat_reset_single_function_counters(PG_FUNCTION_ARGS)
{
    Oid         funcoid = PG_GETARG_OID(0);
 
    pgstat_reset(PGSTAT_KIND_FUNCTION, MyDatabaseId, funcoid);
 
    PG_RETURN_VOID();
}
 
/*
 * Reset statistics of backend with given PID.
 */
Datum
pg_stat_reset_backend_stats(PG_FUNCTION_ARGS)
{
    PGPROC     *proc;
    int         backend_pid = PG_GETARG_INT32(0);
 
    proc = BackendPidGetProc(backend_pid);
 
    /*
     * This could be an auxiliary process but these do not report backend
     * statistics due to pgstat_tracks_backend_bktype(), so there is no need
     * for an extra call to AuxiliaryPidGetProc().
     */
    if (!proc)
        PG_RETURN_VOID();
 
    pgstat_reset(PGSTAT_KIND_BACKEND, InvalidOid, GetNumberFromPGProc(proc));
 
    PG_RETURN_VOID();
}
 
/* Reset SLRU counters (a specific one or all of them). */
Datum
pg_stat_reset_slru(PG_FUNCTION_ARGS)
{
    char       *target = NULL;
 
    if (PG_ARGISNULL(0))
        pgstat_reset_of_kind(PGSTAT_KIND_SLRU);
    else
    {
        target = text_to_cstring(PG_GETARG_TEXT_PP(0));
        pgstat_reset_slru(target);
    }
 
    PG_RETURN_VOID();
}
 
/* Reset replication slots stats (a specific one or all of them). */
Datum
pg_stat_reset_replication_slot(PG_FUNCTION_ARGS)
{
    char       *target = NULL;
 
    if (PG_ARGISNULL(0))
        pgstat_reset_of_kind(PGSTAT_KIND_REPLSLOT);
    else
    {
        target = text_to_cstring(PG_GETARG_TEXT_PP(0));
        pgstat_reset_replslot(target);
    }
 
    PG_RETURN_VOID();
}
 
/* Reset subscription stats (a specific one or all of them) */
Datum
pg_stat_reset_subscription_stats(PG_FUNCTION_ARGS)
{
    Oid         subid;
 
    if (PG_ARGISNULL(0))
    {
        /* Clear all subscription stats */
        pgstat_reset_of_kind(PGSTAT_KIND_SUBSCRIPTION);
    }
    else
    {
        subid = PG_GETARG_OID(0);
 
        if (!OidIsValid(subid))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("invalid subscription OID %u", subid)));
        pgstat_reset(PGSTAT_KIND_SUBSCRIPTION, InvalidOid, subid);
    }
 
    PG_RETURN_VOID();
}
 
Datum
pg_stat_get_archiver(PG_FUNCTION_ARGS)
{
    TupleDesc   tupdesc;
    Datum       values[7] = {0};
    bool        nulls[7] = {0};
    PgStat_ArchiverStats *archiver_stats;
 
    /* Initialise attributes information in the tuple descriptor */
    tupdesc = CreateTemplateTupleDesc(7);
    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "archived_count",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 2, "last_archived_wal",
                       TEXTOID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 3, "last_archived_time",
                       TIMESTAMPTZOID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 4, "failed_count",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 5, "last_failed_wal",
                       TEXTOID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 6, "last_failed_time",
                       TIMESTAMPTZOID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stats_reset",
                       TIMESTAMPTZOID, -1, 0);
 
    BlessTupleDesc(tupdesc);
 
    /* Get statistics about the archiver process */
    archiver_stats = pgstat_fetch_stat_archiver();
 
    /* Fill values and NULLs */
    values[0] = Int64GetDatum(archiver_stats->archived_count);
    if (*(archiver_stats->last_archived_wal) == '\0')
        nulls[1] = true;
    else
        values[1] = CStringGetTextDatum(archiver_stats->last_archived_wal);
 
    if (archiver_stats->last_archived_timestamp == 0)
        nulls[2] = true;
    else
        values[2] = TimestampTzGetDatum(archiver_stats->last_archived_timestamp);
 
    values[3] = Int64GetDatum(archiver_stats->failed_count);
    if (*(archiver_stats->last_failed_wal) == '\0')
        nulls[4] = true;
    else
        values[4] = CStringGetTextDatum(archiver_stats->last_failed_wal);
 
    if (archiver_stats->last_failed_timestamp == 0)
        nulls[5] = true;
    else
        values[5] = TimestampTzGetDatum(archiver_stats->last_failed_timestamp);
 
    if (archiver_stats->stat_reset_timestamp == 0)
        nulls[6] = true;
    else
        values[6] = TimestampTzGetDatum(archiver_stats->stat_reset_timestamp);
 
    /* Returns the record as Datum */
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
 
/*
 * Get the statistics for the replication slot. If the slot statistics is not
 * available, return all-zeroes stats.
 */
Datum
pg_stat_get_replication_slot(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_REPLICATION_SLOT_COLS 10
    text       *slotname_text = PG_GETARG_TEXT_P(0);
    NameData    slotname;
    TupleDesc   tupdesc;
    Datum       values[PG_STAT_GET_REPLICATION_SLOT_COLS] = {0};
    bool        nulls[PG_STAT_GET_REPLICATION_SLOT_COLS] = {0};
    PgStat_StatReplSlotEntry *slotent;
    PgStat_StatReplSlotEntry allzero;
 
    /* Initialise attributes information in the tuple descriptor */
    tupdesc = CreateTemplateTupleDesc(PG_STAT_GET_REPLICATION_SLOT_COLS);
    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "slot_name",
                       TEXTOID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 2, "spill_txns",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 3, "spill_count",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 4, "spill_bytes",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 5, "stream_txns",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 6, "stream_count",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stream_bytes",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 8, "total_txns",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 9, "total_bytes",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 10, "stats_reset",
                       TIMESTAMPTZOID, -1, 0);
    BlessTupleDesc(tupdesc);
 
    namestrcpy(&slotname, text_to_cstring(slotname_text));
    slotent = pgstat_fetch_replslot(slotname);
    if (!slotent)
    {
        /*
         * If the slot is not found, initialise its stats. This is possible if
         * the create slot message is lost.
         */
        memset(&allzero, 0, sizeof(PgStat_StatReplSlotEntry));
        slotent = &allzero;
    }
 
    values[0] = CStringGetTextDatum(NameStr(slotname));
    values[1] = Int64GetDatum(slotent->spill_txns);
    values[2] = Int64GetDatum(slotent->spill_count);
    values[3] = Int64GetDatum(slotent->spill_bytes);
    values[4] = Int64GetDatum(slotent->stream_txns);
    values[5] = Int64GetDatum(slotent->stream_count);
    values[6] = Int64GetDatum(slotent->stream_bytes);
    values[7] = Int64GetDatum(slotent->total_txns);
    values[8] = Int64GetDatum(slotent->total_bytes);
 
    if (slotent->stat_reset_timestamp == 0)
        nulls[9] = true;
    else
        values[9] = TimestampTzGetDatum(slotent->stat_reset_timestamp);
 
    /* Returns the record as Datum */
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
 
/*
 * Get the subscription statistics for the given subscription. If the
 * subscription statistics is not available, return all-zeros stats.
 */
Datum
pg_stat_get_subscription_stats(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_SUBSCRIPTION_STATS_COLS 10
    Oid         subid = PG_GETARG_OID(0);
    TupleDesc   tupdesc;
    Datum       values[PG_STAT_GET_SUBSCRIPTION_STATS_COLS] = {0};
    bool        nulls[PG_STAT_GET_SUBSCRIPTION_STATS_COLS] = {0};
    PgStat_StatSubEntry *subentry;
    PgStat_StatSubEntry allzero;
    int         i = 0;
 
    /* Get subscription stats */
    subentry = pgstat_fetch_stat_subscription(subid);
 
    /* Initialise attributes information in the tuple descriptor */
    tupdesc = CreateTemplateTupleDesc(PG_STAT_GET_SUBSCRIPTION_STATS_COLS);
    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "subid",
                       OIDOID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 2, "apply_error_count",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 3, "sync_error_count",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 4, "confl_insert_exists",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 5, "confl_update_origin_differs",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 6, "confl_update_exists",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 7, "confl_update_missing",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 8, "confl_delete_origin_differs",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 9, "confl_delete_missing",
                       INT8OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 10, "stats_reset",
                       TIMESTAMPTZOID, -1, 0);
    BlessTupleDesc(tupdesc);
 
    if (!subentry)
    {
        /* If the subscription is not found, initialise its stats */
        memset(&allzero, 0, sizeof(PgStat_StatSubEntry));
        subentry = &allzero;
    }
 
    /* subid */
    values[i++] = ObjectIdGetDatum(subid);
 
    /* apply_error_count */
    values[i++] = Int64GetDatum(subentry->apply_error_count);
 
    /* sync_error_count */
    values[i++] = Int64GetDatum(subentry->sync_error_count);
 
    /* conflict count */
    for (int nconflict = 0; nconflict < CONFLICT_NUM_TYPES; nconflict++)
        values[i++] = Int64GetDatum(subentry->conflict_count[nconflict]);
 
    /* stats_reset */
    if (subentry->stat_reset_timestamp == 0)
        nulls[i] = true;
    else
        values[i] = TimestampTzGetDatum(subentry->stat_reset_timestamp);
 
    Assert(i + 1 == PG_STAT_GET_SUBSCRIPTION_STATS_COLS);
 
    /* Returns the record as Datum */
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
 
/*
 * Checks for presence of stats for object with provided kind, database oid,
 * object oid.
 *
 * This is useful for tests, but not really anything else. Therefore not
 * documented.
 */
Datum
pg_stat_have_stats(PG_FUNCTION_ARGS)
{
    char       *stats_type = text_to_cstring(PG_GETARG_TEXT_P(0));
    Oid         dboid = PG_GETARG_OID(1);
    uint64      objid = PG_GETARG_INT64(2);
    PgStat_Kind kind = pgstat_get_kind_from_str(stats_type);
 
    PG_RETURN_BOOL(pgstat_have_entry(kind, dboid, objid));
}