Datum gserialized_gist_joinsel

(

PG_FUNCTION_ARGS

)

Definition at line 1126 of file gserialized_estimate.c.

References DEFAULT_ND_JOINSEL, estimate_join_selectivity(), and pg_get_nd_stats().

Referenced by gserialized_gist_joinsel_2d(), and gserialized_gist_joinsel_nd().

{
        PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);
        /* Oid operator = PG_GETARG_OID(1); */
        List *args = (List *) PG_GETARG_POINTER(2);
        JoinType jointype = (JoinType) PG_GETARG_INT16(3);
        int mode = PG_GETARG_INT32(4);

        Node *arg1, *arg2;
        Var *var1, *var2;
        Oid relid1, relid2;
        
        ND_STATS *stats1, *stats2;
        float8 selectivity;

        /* Only respond to an inner join/unknown context join */
        if (jointype != JOIN_INNER)
        {
                elog(NOTICE, "gserialized_gist_joinsel: jointype %d not supported", jointype);
                PG_RETURN_FLOAT8(DEFAULT_ND_JOINSEL);
        }

        /* Find Oids of the geometry columns we are working with */
        arg1 = (Node*) linitial(args);
        arg2 = (Node*) lsecond(args);
        var1 = (Var*) arg1;
        var2 = (Var*) arg2;

        /* We only do column joins right now, no functional joins */
        /* TODO: handle g1 && ST_Expand(g2) */
        if (!IsA(arg1, Var) || !IsA(arg2, Var))
        {
                elog(DEBUG1, "gserialized_gist_joinsel called with arguments that are not column references");
                PG_RETURN_FLOAT8(DEFAULT_ND_JOINSEL);
        }

        /* What are the Oids of our tables/relations? */
        relid1 = getrelid(var1->varno, root->parse->rtable);
        relid2 = getrelid(var2->varno, root->parse->rtable);

        POSTGIS_DEBUGF(3, "using relations \"%s\" Oid(%d), \"%s\" Oid(%d)", 
                         get_rel_name(relid1) ? get_rel_name(relid1) : "NULL", relid1, get_rel_name(relid2) ? get_rel_name(relid2) : "NULL", relid2); 

        /* Pull the stats from the stats system. */
        stats1 = pg_get_nd_stats(relid1, var1->varattno, mode);
        stats2 = pg_get_nd_stats(relid2, var2->varattno, mode);

        /* If we can't get stats, we have to stop here! */
        if ( ! stats1 )
        {
                POSTGIS_DEBUGF(3, "unable to retrieve stats for \"%s\" Oid(%d)", get_rel_name(relid1) ? get_rel_name(relid1) : "NULL" , relid1);
                PG_RETURN_FLOAT8(DEFAULT_ND_JOINSEL);
        }
        else if ( ! stats2 )
        {
                POSTGIS_DEBUGF(3, "unable to retrieve stats for \"%s\" Oid(%d)", get_rel_name(relid2) ? get_rel_name(relid2) : "NULL", relid2);
                PG_RETURN_FLOAT8(DEFAULT_ND_JOINSEL);
        }

        selectivity = estimate_join_selectivity(stats1, stats2);
        POSTGIS_DEBUGF(2, "got selectivity %g", selectivity);
        
        pfree(stats1);
        pfree(stats2);
        PG_RETURN_FLOAT8(selectivity);
}

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