gserialized_gist_sel()

Datum gserialized_gist_sel

(

PG_FUNCTION_ARGS

)

Definition at line 2174 of file gserialized_estimate.c.

References ovdump::args, DEFAULT_ND_SEL, estimate_selectivity(), FALLBACK_ND_SEL, gbox_to_string(), gserialized_estimated_extent(), nd_stats_to_json(), PG_FUNCTION_INFO_V1(), and pg_nd_stats_from_tuple().

Referenced by gserialized_gist_sel_2d(), and gserialized_gist_sel_nd().

{
        PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);
        /* Oid operator_oid = PG_GETARG_OID(1); */
        List *args = (List *) PG_GETARG_POINTER(2);
        /* int varRelid = PG_GETARG_INT32(3); */
        int mode = PG_GETARG_INT32(4);

        VariableStatData vardata;
        ND_STATS *nd_stats = NULL;

        Node *other;
        Var *self;
        GBOX search_box;
        float8 selectivity = 0;

        POSTGIS_DEBUG(2, "gserialized_gist_sel called");

        /*
         * TODO: This is a big one,
         * All this statistics code *only* tries to generate a valid
         * selectivity for && and &&&. That leaves all the other
         * geometry operators with bad stats! The selectivity
         * calculation should take account of the incoming operator
         * type and do the right thing.
         */

        /* Fail if not a binary opclause (probably shouldn't happen) */
        if (list_length(args) != 2)
        {
                POSTGIS_DEBUG(3, "gserialized_gist_sel: not a binary opclause");
                PG_RETURN_FLOAT8(DEFAULT_ND_SEL);
        }

        /* Find the constant part */
        other = (Node *) linitial(args);
        if ( ! IsA(other, Const) )
        {
                self = (Var *)other;
                other = (Node *) lsecond(args);
        }
        else
        {
                self = (Var *) lsecond(args);
        }

        if ( ! IsA(other, Const) )
        {
                POSTGIS_DEBUG(3, " no constant arguments - returning a default selectivity");
                PG_RETURN_FLOAT8(DEFAULT_ND_SEL);
        }

        /* Convert the constant to a BOX */
        if( ! gserialized_datum_get_gbox_p(((Const*)other)->constvalue, &search_box) )
        {
                POSTGIS_DEBUG(3, "search box is EMPTY");
                PG_RETURN_FLOAT8(0.0);
        }
        POSTGIS_DEBUGF(4, " requested search box is: %s", gbox_to_string(&search_box));

        /* Get pg_statistic row */
        examine_variable(root, (Node*)self, 0, &vardata);
        if ( vardata.statsTuple ) {
                nd_stats = pg_nd_stats_from_tuple(vardata.statsTuple, mode);
        }
        ReleaseVariableStats(vardata);

        if ( ! nd_stats )
        {
                POSTGIS_DEBUG(3, " unable to load stats from syscache, not analyzed yet?");
                PG_RETURN_FLOAT8(FALLBACK_ND_SEL);
        }

        POSTGIS_DEBUGF(4, " got stats:\n%s", nd_stats_to_json(nd_stats));

        /* Do the estimation! */
        selectivity = estimate_selectivity(&search_box, nd_stats, mode);
        POSTGIS_DEBUGF(3, " returning computed value: %f", selectivity);

        pfree(nd_stats);
        PG_RETURN_FLOAT8(selectivity);
}

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