pgstatfuncs.c

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/*-------------------------------------------------------------------------
 *
 * pgstatfuncs.c
 *    Functions for accessing the statistics collector data
 *
 * Portions Copyright (c) 1996-2013, 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 "catalog/pg_type.h"
#include "funcapi.h"
#include "libpq/ip.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "utils/builtins.h"
#include "utils/inet.h"
#include "utils/timestamp.h"

/* bogus ... these externs should be in a header file */
extern Datum pg_stat_get_numscans(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_tuples_returned(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_tuples_fetched(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_tuples_inserted(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_tuples_updated(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_tuples_deleted(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_tuples_hot_updated(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_live_tuples(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_dead_tuples(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_blocks_fetched(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_blocks_hit(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_last_vacuum_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_last_autovacuum_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_last_analyze_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_last_autoanalyze_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_vacuum_count(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_autovacuum_count(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_analyze_count(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_autoanalyze_count(PG_FUNCTION_ARGS);

extern Datum pg_stat_get_function_calls(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_function_total_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_function_self_time(PG_FUNCTION_ARGS);

extern Datum pg_stat_get_backend_idset(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_activity(PG_FUNCTION_ARGS);
extern Datum pg_backend_pid(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_pid(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_dbid(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_userid(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_activity(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_waiting(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_activity_start(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_xact_start(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_start(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_backend_client_port(PG_FUNCTION_ARGS);

extern Datum pg_stat_get_db_numbackends(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_xact_commit(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_xact_rollback(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_blocks_fetched(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_blocks_hit(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_tuples_returned(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_tuples_fetched(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_tuples_inserted(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_tuples_updated(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_tuples_deleted(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_conflict_tablespace(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_conflict_lock(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_conflict_snapshot(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_conflict_bufferpin(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_conflict_startup_deadlock(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_conflict_all(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_deadlocks(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_stat_reset_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_temp_files(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_temp_bytes(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_blk_read_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_db_blk_write_time(PG_FUNCTION_ARGS);

extern Datum pg_stat_get_bgwriter_timed_checkpoints(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_bgwriter_requested_checkpoints(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_checkpoint_write_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_checkpoint_sync_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_bgwriter_buf_written_checkpoints(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_bgwriter_buf_written_clean(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_bgwriter_maxwritten_clean(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_bgwriter_stat_reset_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_buf_written_backend(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_buf_fsync_backend(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_buf_alloc(PG_FUNCTION_ARGS);

extern Datum pg_stat_get_xact_numscans(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_tuples_returned(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_tuples_fetched(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_tuples_inserted(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_tuples_updated(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_tuples_deleted(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_tuples_hot_updated(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_blocks_fetched(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_blocks_hit(PG_FUNCTION_ARGS);

extern Datum pg_stat_get_xact_function_calls(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_function_total_time(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_function_self_time(PG_FUNCTION_ARGS);

extern Datum pg_stat_clear_snapshot(PG_FUNCTION_ARGS);
extern Datum pg_stat_reset(PG_FUNCTION_ARGS);
extern Datum pg_stat_reset_shared(PG_FUNCTION_ARGS);
extern Datum pg_stat_reset_single_table_counters(PG_FUNCTION_ARGS);
extern Datum pg_stat_reset_single_function_counters(PG_FUNCTION_ARGS);

/* Global bgwriter statistics, from bgwriter.c */
extern PgStat_MsgBgWriter bgwriterStats;

Datum
pg_stat_get_numscans(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->numscans);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_tuples_returned(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->tuples_returned);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_tuples_fetched(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->tuples_fetched);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_tuples_inserted(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->tuples_inserted);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_tuples_updated(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->tuples_updated);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_tuples_deleted(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->tuples_deleted);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_tuples_hot_updated(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->tuples_hot_updated);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_live_tuples(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->n_live_tuples);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_dead_tuples(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->n_dead_tuples);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_blocks_fetched(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->blocks_fetched);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_blocks_hit(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->blocks_hit);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_last_vacuum_time(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->vacuum_timestamp;

    if (result == 0)
        PG_RETURN_NULL();
    else
        PG_RETURN_TIMESTAMPTZ(result);
}

Datum
pg_stat_get_last_autovacuum_time(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->autovac_vacuum_timestamp;

    if (result == 0)
        PG_RETURN_NULL();
    else
        PG_RETURN_TIMESTAMPTZ(result);
}

Datum
pg_stat_get_last_analyze_time(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->analyze_timestamp;

    if (result == 0)
        PG_RETURN_NULL();
    else
        PG_RETURN_TIMESTAMPTZ(result);
}

Datum
pg_stat_get_last_autoanalyze_time(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->autovac_analyze_timestamp;

    if (result == 0)
        PG_RETURN_NULL();
    else
        PG_RETURN_TIMESTAMPTZ(result);
}

Datum
pg_stat_get_vacuum_count(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->vacuum_count);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_autovacuum_count(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->autovac_vacuum_count);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_analyze_count(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->analyze_count);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_autoanalyze_count(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->autovac_analyze_count);

    PG_RETURN_INT64(result);
}

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->f_numcalls);
}

Datum
pg_stat_get_function_total_time(PG_FUNCTION_ARGS)
{
    Oid         funcid = PG_GETARG_OID(0);
    PgStat_StatFuncEntry *funcentry;

    if ((funcentry = pgstat_fetch_stat_funcentry(funcid)) == NULL)
        PG_RETURN_NULL();
    /* convert counter from microsec to millisec for display */
    PG_RETURN_FLOAT8(((double) funcentry->f_total_time) / 1000.0);
}

Datum
pg_stat_get_function_self_time(PG_FUNCTION_ARGS)
{
    Oid         funcid = PG_GETARG_OID(0);
    PgStat_StatFuncEntry *funcentry;

    if ((funcentry = pgstat_fetch_stat_funcentry(funcid)) == NULL)
        PG_RETURN_NULL();
    /* convert counter from microsec to millisec for display */
    PG_RETURN_FLOAT8(((double) funcentry->f_self_time) / 1000.0);
}

Datum
pg_stat_get_backend_idset(PG_FUNCTION_ARGS)
{
    FuncCallContext *funcctx;
    int        *fctx;
    int32       result;

    /* 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,
                                  2 * sizeof(int));
        funcctx->user_fctx = fctx;

        fctx[0] = 0;
        fctx[1] = pgstat_fetch_stat_numbackends();
    }

    /* stuff done on every call of the function */
    funcctx = SRF_PERCALL_SETUP();
    fctx = funcctx->user_fctx;

    fctx[0] += 1;
    result = fctx[0];

    if (result <= fctx[1])
    {
        /* do when there is more left to send */
        SRF_RETURN_NEXT(funcctx, Int32GetDatum(result));
    }
    else
    {
        /* do when there is no more left */
        SRF_RETURN_DONE(funcctx);
    }
}

Datum
pg_stat_get_activity(PG_FUNCTION_ARGS)
{
    FuncCallContext *funcctx;

    if (SRF_IS_FIRSTCALL())
    {
        MemoryContext oldcontext;
        TupleDesc   tupdesc;

        funcctx = SRF_FIRSTCALL_INIT();

        oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

        tupdesc = CreateTemplateTupleDesc(14, false);
        TupleDescInitEntry(tupdesc, (AttrNumber) 1, "datid",
                           OIDOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 2, "pid",
                           INT4OID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 3, "usesysid",
                           OIDOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 4, "application_name",
                           TEXTOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 5, "state",
                           TEXTOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 6, "query",
                           TEXTOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 7, "waiting",
                           BOOLOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 8, "act_start",
                           TIMESTAMPTZOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 9, "query_start",
                           TIMESTAMPTZOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 10, "backend_start",
                           TIMESTAMPTZOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 11, "state_change",
                           TIMESTAMPTZOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 12, "client_addr",
                           INETOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 13, "client_hostname",
                           TEXTOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 14, "client_port",
                           INT4OID, -1, 0);

        funcctx->tuple_desc = BlessTupleDesc(tupdesc);

        funcctx->user_fctx = palloc0(sizeof(int));
        if (PG_ARGISNULL(0))
        {
            /* Get all backends */
            funcctx->max_calls = pgstat_fetch_stat_numbackends();
        }
        else
        {
            /*
             * Get one backend - locate by pid.
             *
             * We lookup the backend early, so we can return zero rows if it
             * doesn't exist, instead of returning a single row full of NULLs.
             */
            int         pid = PG_GETARG_INT32(0);
            int         i;
            int         n = pgstat_fetch_stat_numbackends();

            for (i = 1; i <= n; i++)
            {
                PgBackendStatus *be = pgstat_fetch_stat_beentry(i);

                if (be)
                {
                    if (be->st_procpid == pid)
                    {
                        *(int *) (funcctx->user_fctx) = i;
                        break;
                    }
                }
            }

            if (*(int *) (funcctx->user_fctx) == 0)
                /* Pid not found, return zero rows */
                funcctx->max_calls = 0;
            else
                funcctx->max_calls = 1;
        }

        MemoryContextSwitchTo(oldcontext);
    }

    /* stuff done on every call of the function */
    funcctx = SRF_PERCALL_SETUP();

    if (funcctx->call_cntr < funcctx->max_calls)
    {
        /* for each row */
        Datum       values[14];
        bool        nulls[14];
        HeapTuple   tuple;
        PgBackendStatus *beentry;
        SockAddr    zero_clientaddr;

        MemSet(values, 0, sizeof(values));
        MemSet(nulls, 0, sizeof(nulls));

        if (*(int *) (funcctx->user_fctx) > 0)
        {
            /* Get specific pid slot */
            beentry = pgstat_fetch_stat_beentry(*(int *) (funcctx->user_fctx));
        }
        else
        {
            /* Get the next one in the list */
            beentry = pgstat_fetch_stat_beentry(funcctx->call_cntr + 1);        /* 1-based index */
        }
        if (!beentry)
        {
            int         i;

            for (i = 0; i < sizeof(nulls) / sizeof(nulls[0]); i++)
                nulls[i] = true;

            nulls[5] = false;
            values[5] = CStringGetTextDatum("<backend information not available>");

            tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
            SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
        }

        /* Values available to all callers */
        values[0] = ObjectIdGetDatum(beentry->st_databaseid);
        values[1] = Int32GetDatum(beentry->st_procpid);
        values[2] = ObjectIdGetDatum(beentry->st_userid);
        if (beentry->st_appname)
            values[3] = CStringGetTextDatum(beentry->st_appname);
        else
            nulls[3] = true;

        /* Values only available to same user or superuser */
        if (superuser() || beentry->st_userid == GetUserId())
        {
            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;
            }

            values[5] = CStringGetTextDatum(beentry->st_activity);
            values[6] = BoolGetDatum(beentry->st_waiting);

            if (beentry->st_xact_start_timestamp != 0)
                values[7] = TimestampTzGetDatum(beentry->st_xact_start_timestamp);
            else
                nulls[7] = true;

            if (beentry->st_activity_start_timestamp != 0)
                values[8] = TimestampTzGetDatum(beentry->st_activity_start_timestamp);
            else
                nulls[8] = true;

            if (beentry->st_proc_start_timestamp != 0)
                values[9] = TimestampTzGetDatum(beentry->st_proc_start_timestamp);
            else
                nulls[9] = true;

            if (beentry->st_state_start_timestamp != 0)
                values[10] = TimestampTzGetDatum(beentry->st_state_start_timestamp);
            else
                nulls[10] = true;

            /* A zeroed client addr means we don't know */
            memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
            if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
                       sizeof(zero_clientaddr) == 0))
            {
                nulls[11] = true;
                nulls[12] = true;
                nulls[13] = true;
            }
            else
            {
                if (beentry->st_clientaddr.addr.ss_family == AF_INET
#ifdef HAVE_IPV6
                    || beentry->st_clientaddr.addr.ss_family == AF_INET6
#endif
                    )
                {
                    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[11] = DirectFunctionCall1(inet_in,
                                               CStringGetDatum(remote_host));
                        if (beentry->st_clienthostname)
                            values[12] = CStringGetTextDatum(beentry->st_clienthostname);
                        else
                            nulls[12] = true;
                        values[13] = Int32GetDatum(atoi(remote_port));
                    }
                    else
                    {
                        nulls[11] = true;
                        nulls[12] = true;
                        nulls[13] = 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[11] = true;
                    nulls[12] = true;
                    values[13] = DatumGetInt32(-1);
                }
                else
                {
                    /* Unknown address type, should never happen */
                    nulls[11] = true;
                    nulls[12] = true;
                    nulls[13] = true;
                }
            }
        }
        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;
        }

        tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);

        SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
    }
    else
    {
        /* nothing left */
        SRF_RETURN_DONE(funcctx);
    }
}


Datum
pg_backend_pid(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT32(MyProcPid);
}


Datum
pg_stat_get_backend_pid(PG_FUNCTION_ARGS)
{
    int32       beid = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    PG_RETURN_INT32(beentry->st_procpid);
}


Datum
pg_stat_get_backend_dbid(PG_FUNCTION_ARGS)
{
    int32       beid = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    PG_RETURN_OID(beentry->st_databaseid);
}


Datum
pg_stat_get_backend_userid(PG_FUNCTION_ARGS)
{
    int32       beid = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    PG_RETURN_OID(beentry->st_userid);
}


Datum
pg_stat_get_backend_activity(PG_FUNCTION_ARGS)
{
    int32       beid = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
    const char *activity;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        activity = "<backend information not available>";
    else if (!superuser() && beentry->st_userid != GetUserId())
        activity = "<insufficient privilege>";
    else if (*(beentry->st_activity) == '\0')
        activity = "<command string not enabled>";
    else
        activity = beentry->st_activity;

    PG_RETURN_TEXT_P(cstring_to_text(activity));
}


Datum
pg_stat_get_backend_waiting(PG_FUNCTION_ARGS)
{
    int32       beid = PG_GETARG_INT32(0);
    bool        result;
    PgBackendStatus *beentry;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    if (!superuser() && beentry->st_userid != GetUserId())
        PG_RETURN_NULL();

    result = beentry->st_waiting;

    PG_RETURN_BOOL(result);
}


Datum
pg_stat_get_backend_activity_start(PG_FUNCTION_ARGS)
{
    int32       beid = PG_GETARG_INT32(0);
    TimestampTz result;
    PgBackendStatus *beentry;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    if (!superuser() && beentry->st_userid != GetUserId())
        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       beid = PG_GETARG_INT32(0);
    TimestampTz result;
    PgBackendStatus *beentry;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    if (!superuser() && beentry->st_userid != GetUserId())
        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       beid = PG_GETARG_INT32(0);
    TimestampTz result;
    PgBackendStatus *beentry;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    if (!superuser() && beentry->st_userid != GetUserId())
        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       beid = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
    SockAddr    zero_clientaddr;
    char        remote_host[NI_MAXHOST];
    int         ret;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    if (!superuser() && beentry->st_userid != GetUserId())
        PG_RETURN_NULL();

    /* A zeroed client addr means we don't know */
    memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
    if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
               sizeof(zero_clientaddr) == 0))
        PG_RETURN_NULL();

    switch (beentry->st_clientaddr.addr.ss_family)
    {
        case AF_INET:
#ifdef HAVE_IPV6
        case AF_INET6:
#endif
            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_INET_P(DirectFunctionCall1(inet_in,
                                         CStringGetDatum(remote_host)));
}

Datum
pg_stat_get_backend_client_port(PG_FUNCTION_ARGS)
{
    int32       beid = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
    SockAddr    zero_clientaddr;
    char        remote_port[NI_MAXSERV];
    int         ret;

    if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
        PG_RETURN_NULL();

    if (!superuser() && beentry->st_userid != GetUserId())
        PG_RETURN_NULL();

    /* A zeroed client addr means we don't know */
    memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
    if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
               sizeof(zero_clientaddr) == 0))
        PG_RETURN_NULL();

    switch (beentry->st_clientaddr.addr.ss_family)
    {
        case AF_INET:
#ifdef HAVE_IPV6
        case AF_INET6:
#endif
            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         beid;

    result = 0;
    for (beid = 1; beid <= tot_backends; beid++)
    {
        PgBackendStatus *beentry = pgstat_fetch_stat_beentry(beid);

        if (beentry && beentry->st_databaseid == dbid)
            result++;
    }

    PG_RETURN_INT32(result);
}


Datum
pg_stat_get_db_xact_commit(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->n_xact_commit);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_xact_rollback(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->n_xact_rollback);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_blocks_fetched(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->n_blocks_fetched);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_blocks_hit(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->n_blocks_hit);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_tuples_returned(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->n_tuples_returned);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_tuples_fetched(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->n_tuples_fetched);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_tuples_inserted(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->n_tuples_inserted);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_tuples_updated(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->n_tuples_updated);

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_tuples_deleted(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->n_tuples_deleted);

    PG_RETURN_INT64(result);
}

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_temp_files(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 = dbentry->n_temp_files;

    PG_RETURN_INT64(result);
}


Datum
pg_stat_get_db_temp_bytes(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 = dbentry->n_temp_bytes;

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_db_conflict_tablespace(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->n_conflict_tablespace);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_db_conflict_lock(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->n_conflict_lock);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_db_conflict_snapshot(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->n_conflict_snapshot);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_db_conflict_bufferpin(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->n_conflict_bufferpin);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_db_conflict_startup_deadlock(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->n_conflict_startup_deadlock);

    PG_RETURN_INT64(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->n_conflict_tablespace +
                          dbentry->n_conflict_lock +
                          dbentry->n_conflict_snapshot +
                          dbentry->n_conflict_bufferpin +
                          dbentry->n_conflict_startup_deadlock);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_db_deadlocks(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->n_deadlocks);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_db_blk_read_time(PG_FUNCTION_ARGS)
{
    Oid         dbid = PG_GETARG_OID(0);
    double      result;
    PgStat_StatDBEntry *dbentry;

    /* convert counter from microsec to millisec for display */
    if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
        result = 0;
    else
        result = ((double) dbentry->n_block_read_time) / 1000.0;

    PG_RETURN_FLOAT8(result);
}

Datum
pg_stat_get_db_blk_write_time(PG_FUNCTION_ARGS)
{
    Oid         dbid = PG_GETARG_OID(0);
    double      result;
    PgStat_StatDBEntry *dbentry;

    /* convert counter from microsec to millisec for display */
    if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
        result = 0;
    else
        result = ((double) dbentry->n_block_write_time) / 1000.0;

    PG_RETURN_FLOAT8(result);
}

Datum
pg_stat_get_bgwriter_timed_checkpoints(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_global()->timed_checkpoints);
}

Datum
pg_stat_get_bgwriter_requested_checkpoints(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_global()->requested_checkpoints);
}

Datum
pg_stat_get_bgwriter_buf_written_checkpoints(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_global()->buf_written_checkpoints);
}

Datum
pg_stat_get_bgwriter_buf_written_clean(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_global()->buf_written_clean);
}

Datum
pg_stat_get_bgwriter_maxwritten_clean(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_global()->maxwritten_clean);
}

Datum
pg_stat_get_checkpoint_write_time(PG_FUNCTION_ARGS)
{
    /* time is already in msec, just convert to double for presentation */
    PG_RETURN_FLOAT8((double) pgstat_fetch_global()->checkpoint_write_time);
}

Datum
pg_stat_get_checkpoint_sync_time(PG_FUNCTION_ARGS)
{
    /* time is already in msec, just convert to double for presentation */
    PG_RETURN_FLOAT8((double) pgstat_fetch_global()->checkpoint_sync_time);
}

Datum
pg_stat_get_bgwriter_stat_reset_time(PG_FUNCTION_ARGS)
{
    PG_RETURN_TIMESTAMPTZ(pgstat_fetch_global()->stat_reset_timestamp);
}

Datum
pg_stat_get_buf_written_backend(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_global()->buf_written_backend);
}

Datum
pg_stat_get_buf_fsync_backend(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_global()->buf_fsync_backend);
}

Datum
pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
{
    PG_RETURN_INT64(pgstat_fetch_global()->buf_alloc);
}

Datum
pg_stat_get_xact_numscans(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->t_counts.t_numscans);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_tuples_returned(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->t_counts.t_tuples_returned);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_tuples_fetched(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->t_counts.t_tuples_fetched);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_tuples_inserted(PG_FUNCTION_ARGS)
{
    Oid         relid = PG_GETARG_OID(0);
    int64       result;
    PgStat_TableStatus *tabentry;
    PgStat_TableXactStatus *trans;

    if ((tabentry = find_tabstat_entry(relid)) == NULL)
        result = 0;
    else
    {
        result = tabentry->t_counts.t_tuples_inserted;
        /* live subtransactions' counts aren't in t_tuples_inserted yet */
        for (trans = tabentry->trans; trans != NULL; trans = trans->upper)
            result += trans->tuples_inserted;
    }

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_tuples_updated(PG_FUNCTION_ARGS)
{
    Oid         relid = PG_GETARG_OID(0);
    int64       result;
    PgStat_TableStatus *tabentry;
    PgStat_TableXactStatus *trans;

    if ((tabentry = find_tabstat_entry(relid)) == NULL)
        result = 0;
    else
    {
        result = tabentry->t_counts.t_tuples_updated;
        /* live subtransactions' counts aren't in t_tuples_updated yet */
        for (trans = tabentry->trans; trans != NULL; trans = trans->upper)
            result += trans->tuples_updated;
    }

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_tuples_deleted(PG_FUNCTION_ARGS)
{
    Oid         relid = PG_GETARG_OID(0);
    int64       result;
    PgStat_TableStatus *tabentry;
    PgStat_TableXactStatus *trans;

    if ((tabentry = find_tabstat_entry(relid)) == NULL)
        result = 0;
    else
    {
        result = tabentry->t_counts.t_tuples_deleted;
        /* live subtransactions' counts aren't in t_tuples_deleted yet */
        for (trans = tabentry->trans; trans != NULL; trans = trans->upper)
            result += trans->tuples_deleted;
    }

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_tuples_hot_updated(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->t_counts.t_tuples_hot_updated);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_blocks_fetched(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->t_counts.t_blocks_fetched);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_blocks_hit(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->t_counts.t_blocks_hit);

    PG_RETURN_INT64(result);
}

Datum
pg_stat_get_xact_function_calls(PG_FUNCTION_ARGS)
{
    Oid         funcid = PG_GETARG_OID(0);
    PgStat_BackendFunctionEntry *funcentry;

    if ((funcentry = find_funcstat_entry(funcid)) == NULL)
        PG_RETURN_NULL();
    PG_RETURN_INT64(funcentry->f_counts.f_numcalls);
}

Datum
pg_stat_get_xact_function_total_time(PG_FUNCTION_ARGS)
{
    Oid         funcid = PG_GETARG_OID(0);
    PgStat_BackendFunctionEntry *funcentry;

    if ((funcentry = find_funcstat_entry(funcid)) == NULL)
        PG_RETURN_NULL();
    PG_RETURN_FLOAT8(INSTR_TIME_GET_MILLISEC(funcentry->f_counts.f_total_time));
}

Datum
pg_stat_get_xact_function_self_time(PG_FUNCTION_ARGS)
{
    Oid         funcid = PG_GETARG_OID(0);
    PgStat_BackendFunctionEntry *funcentry;

    if ((funcentry = find_funcstat_entry(funcid)) == NULL)
        PG_RETURN_NULL();
    PG_RETURN_FLOAT8(INSTR_TIME_GET_MILLISEC(funcentry->f_counts.f_self_time));
}


/* Discard the active statistics snapshot */
Datum
pg_stat_clear_snapshot(PG_FUNCTION_ARGS)
{
    pgstat_clear_snapshot();

    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 */
Datum
pg_stat_reset_shared(PG_FUNCTION_ARGS)
{
    char       *target = text_to_cstring(PG_GETARG_TEXT_PP(0));

    pgstat_reset_shared_counters(target);

    PG_RETURN_VOID();
}

/* Reset a a single counter in the current database */
Datum
pg_stat_reset_single_table_counters(PG_FUNCTION_ARGS)
{
    Oid         taboid = PG_GETARG_OID(0);

    pgstat_reset_single_counter(taboid, RESET_TABLE);

    PG_RETURN_VOID();
}

Datum
pg_stat_reset_single_function_counters(PG_FUNCTION_ARGS)
{
    Oid         funcoid = PG_GETARG_OID(0);

    pgstat_reset_single_counter(funcoid, RESET_FUNCTION);

    PG_RETURN_VOID();
}