gserialized_estimated_extent()

Datum gserialized_estimated_extent

(

PG_FUNCTION_ARGS

)

Definition at line 2314 of file gserialized_estimate.c.

{
        char *nsp = NULL;
        char *tbl = NULL;
        text *col = NULL;
        char *nsp_tbl = NULL;
        Oid tbl_oid, idx_oid = 0;
        ND_STATS *nd_stats;
        GBOX *gbox = NULL;
        bool only_parent = false;
        int key_type, att_num;
        size_t sz;
 
        /* We need to initialize the internal cache to access it later via postgis_oid() */
        postgis_initialize_cache();
 
        if ( PG_NARGS() == 4 )
        {
                nsp = text_to_cstring(PG_GETARG_TEXT_P(0));
                tbl = text_to_cstring(PG_GETARG_TEXT_P(1));
                col = PG_GETARG_TEXT_P(2);
                only_parent = PG_GETARG_BOOL(3);
                sz = strlen(nsp) + strlen(tbl) + 6;
                nsp_tbl = palloc(sz);
                snprintf(nsp_tbl, sz, "\"%s\".\"%s\"", nsp, tbl);
                tbl_oid = DatumGetObjectId(DirectFunctionCall1(regclassin, CStringGetDatum(nsp_tbl)));
                pfree(nsp_tbl);
        }
        else if ( PG_NARGS() == 3 )
        {
                nsp = text_to_cstring(PG_GETARG_TEXT_P(0));
                tbl = text_to_cstring(PG_GETARG_TEXT_P(1));
                col = PG_GETARG_TEXT_P(2);
                sz = strlen(nsp) + strlen(tbl) + 6;
                nsp_tbl = palloc(sz);
                snprintf(nsp_tbl, sz, "\"%s\".\"%s\"", nsp, tbl);
                tbl_oid = DatumGetObjectId(DirectFunctionCall1(regclassin, CStringGetDatum(nsp_tbl)));
                pfree(nsp_tbl);
        }
        else if ( PG_NARGS() == 2 )
        {
                tbl = text_to_cstring(PG_GETARG_TEXT_P(0));
                col = PG_GETARG_TEXT_P(1);
                sz = strlen(tbl) + 3;
                nsp_tbl = palloc(sz);
                snprintf(nsp_tbl, sz, "\"%s\"", tbl);
                tbl_oid = DatumGetObjectId(DirectFunctionCall1(regclassin, CStringGetDatum(nsp_tbl)));
                pfree(nsp_tbl);
        }
        else
        {
                elog(ERROR, "estimated_extent() called with wrong number of arguments");
                PG_RETURN_NULL();
        }
 
        /* Read the extent from the head of the spatial index, if there is one */
 
        idx_oid = table_get_spatial_index(tbl_oid, col, &key_type, &att_num);
        if (idx_oid)
        {
                /* TODO: how about only_parent ? */
                gbox = spatial_index_read_extent(idx_oid, key_type, att_num);
                POSTGIS_DEBUGF(2, "index for \"%s.%s\" exists, reading gbox from there", tbl, text_to_cstring(col));
                if ( ! gbox ) PG_RETURN_NULL();
        }
        else
        {
                POSTGIS_DEBUGF(2, "index for \"%s.%s\" does not exist", tbl, text_to_cstring(col));
 
                /* Fall back to reading the stats, if no index is found */
 
                /* Estimated extent only returns 2D bounds, so use mode 2 */
                nd_stats = pg_get_nd_stats_by_name(tbl_oid, col, 2, only_parent);
 
                /* Error out on no stats */
                if ( ! nd_stats ) {
                        elog(WARNING, "stats for \"%s.%s\" do not exist", tbl, text_to_cstring(col));
                        PG_RETURN_NULL();
                }
 
                /* Construct the box */
                gbox = palloc(sizeof(GBOX));
                FLAGS_SET_GEODETIC(gbox->flags, 0);
                FLAGS_SET_Z(gbox->flags, 0);
                FLAGS_SET_M(gbox->flags, 0);
                gbox->xmin = nd_stats->extent.min[0];
                gbox->xmax = nd_stats->extent.max[0];
                gbox->ymin = nd_stats->extent.min[1];
                gbox->ymax = nd_stats->extent.max[1];
                pfree(nd_stats);
        }
 
        PG_RETURN_POINTER(gbox);
}

References ND_STATS_T::extent, GBOX::flags, FLAGS_SET_GEODETIC, FLAGS_SET_M, FLAGS_SET_Z, ND_BOX_T::max, ND_BOX_T::min, pg_get_nd_stats_by_name(), spatial_index_read_extent(), table_get_spatial_index(), GBOX::xmax, GBOX::xmin, GBOX::ymax, and GBOX::ymin.

Referenced by geometry_estimated_extent().

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