pg_get_nd_stats()

static ND_STATS* pg_get_nd_stats ( const Oid  table_oid, AttrNumber  att_num, int  mode, bool  only_parent  )

static

Pull the stats object from the PgSQL system catalogs.

Used by the selectivity functions and the debugging functions.

Definition at line 951 of file gserialized_estimate.c.

{
        HeapTuple stats_tuple = NULL;
        ND_STATS *nd_stats;
 
        /* First pull the stats tuple for the whole tree */
        if ( ! only_parent )
        {
                POSTGIS_DEBUGF(2, "searching whole tree stats for \"%s\"", get_rel_name(table_oid)? get_rel_name(table_oid) : "NULL");
                stats_tuple = SearchSysCache3(STATRELATTINH, ObjectIdGetDatum(table_oid), Int16GetDatum(att_num), BoolGetDatum(true));
                if ( stats_tuple )
                        POSTGIS_DEBUGF(2, "found whole tree stats for \"%s\"", get_rel_name(table_oid)? get_rel_name(table_oid) : "NULL");
        }
        /* Fall-back to main table stats only, if not found for whole tree or explicitly ignored */
        if ( only_parent || ! stats_tuple )
        {
                POSTGIS_DEBUGF(2, "searching parent table stats for \"%s\"", get_rel_name(table_oid)? get_rel_name(table_oid) : "NULL");
                stats_tuple = SearchSysCache3(STATRELATTINH, ObjectIdGetDatum(table_oid), Int16GetDatum(att_num), BoolGetDatum(false));
                if ( stats_tuple )
                        POSTGIS_DEBUGF(2, "found parent table stats for \"%s\"", get_rel_name(table_oid)? get_rel_name(table_oid) : "NULL");
        }
        if ( ! stats_tuple )
        {
                POSTGIS_DEBUGF(2, "stats for \"%s\" do not exist", get_rel_name(table_oid)? get_rel_name(table_oid) : "NULL");
                return NULL;
        }
 
        nd_stats = pg_nd_stats_from_tuple(stats_tuple, mode);
        ReleaseSysCache(stats_tuple);
        if ( ! nd_stats )
        {
                POSTGIS_DEBUGF(2,
                        "histogram for attribute %d of table \"%s\" does not exist?",
                        att_num, get_rel_name(table_oid));
        }
 
        return nd_stats;
}

References pg_nd_stats_from_tuple().

Referenced by gserialized_gist_joinsel(), and pg_get_nd_stats_by_name().

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