#include "utils/builtins.h"
#include "utils/syscache.h"
#include "utils/rel.h"
+#include "utils/selfuncs.h"
#include "../postgis_config.h"
return TRUE;
}
+static ND_STATS*
+pg_nd_stats_from_tuple(HeapTuple stats_tuple, int mode)
+{
+ int stats_kind = STATISTIC_KIND_ND;
+ int rv, nvalues;
+ float4 *floatptr;
+ ND_STATS *nd_stats;
+
+ /* If we're in 2D mode, set the kind appropriately */
+ if ( mode == 2 ) stats_kind = STATISTIC_KIND_2D;
+
+ /* Then read the geom status histogram from that */
+ rv = get_attstatsslot(stats_tuple, 0, 0, stats_kind, InvalidOid,
+ NULL, NULL, NULL, &floatptr, &nvalues);
+ if ( ! rv ) {
+ POSTGIS_DEBUGF(2,
+ "no slot of kind %d in stats tuple", stats_kind);
+ return NULL;
+ }
+
+ /* Clone the stats here so we can release the attstatsslot immediately */
+ nd_stats = palloc(sizeof(float) * nvalues);
+ memcpy(nd_stats, floatptr, sizeof(float) * nvalues);
+
+ /* Clean up */
+ free_attstatsslot(0, NULL, 0, floatptr, nvalues);
+
+ return nd_stats;
+}
/**
* Pull the stats object from the PgSQL system catalogs. Used
pg_get_nd_stats(const Oid table_oid, AttrNumber att_num, int mode)
{
HeapTuple stats_tuple;
- float4 *floatptr;
ND_STATS *nd_stats;
- int rv, nvalues;
- int stats_kind = STATISTIC_KIND_ND;
/* First pull the stats tuple */
stats_tuple = SearchSysCache2(STATRELATT, table_oid, att_num);
POSTGIS_DEBUGF(2, "stats for \"%s\" do not exist", get_rel_name(table_oid)? get_rel_name(table_oid) : "NULL");
return NULL;
}
-
- /* If we're in 2D mode, set the kind appropriately */
- if ( mode == 2 )
- stats_kind = STATISTIC_KIND_2D;
-
- /* Then read the geom status histogram from that */
- rv = get_attstatsslot(stats_tuple, 0, 0, stats_kind, InvalidOid, NULL, NULL, NULL, &floatptr, &nvalues);
- if ( ! rv )
+
+ nd_stats = pg_nd_stats_from_tuple(stats_tuple, mode);
+ ReleaseSysCache(stats_tuple);
+ if ( ! nd_stats )
{
- ReleaseSysCache(stats_tuple);
- POSTGIS_DEBUGF(2, "histogram for \"%s\" does not exist?", get_rel_name(table_oid));
- return NULL;
+ POSTGIS_DEBUGF(2,
+ "histogram for attribute %d of table \"%s\" does not exist?",
+ att_num, get_rel_name(table_oid));
}
- /* Clone the stats here so we can release the attstatsslot immediately */
- nd_stats = palloc(sizeof(float) * nvalues);
- memcpy(nd_stats, floatptr, sizeof(float) * nvalues);
-
- /* Clean up */
- free_attstatsslot(0, NULL, 0, floatptr, nvalues);
- ReleaseSysCache(stats_tuple);
-
return nd_stats;
}
-
/**
* Pull the stats object from the PgSQL system catalogs. The
* debugging functions are taking human input (table names)
/* int varRelid = PG_GETARG_INT32(3); */
int mode = PG_GETARG_INT32(4);
- Oid relid;
- ND_STATS *nd_stats;
+ VariableStatData vardata;
+ ND_STATS *nd_stats = NULL;
Node *other;
Var *self;
PG_RETURN_FLOAT8(DEFAULT_ND_SEL);
}
- /*
- * We don't have a nice <const> && <var> or <var> && <const>
- * situation here. <const> && <const> would probably get evaluated
- * away by PgSQL earlier on. <func> && <const> is harder, and the
- * case we get often is <const> && ST_Expand(<var>), which does
- * actually have a subtly different selectivity than a bae
- * <const> && <var> call. It's calculatable though, by expanding
- * every cell in the histgram appropriately.
- *
- * Discussion: http://trac.osgeo.org/postgis/ticket/1828
- *
- * To do? Do variable selectivity based on the <func> node.
- */
- if ( ! IsA(self, Var) )
- {
- POSTGIS_DEBUG(3, " no bare variable argument ? - returning a moderate selectivity");
- PG_RETURN_FLOAT8(FALLBACK_ND_SEL);
- }
-
/* Convert the constant to a BOX */
if( ! gserialized_datum_get_gbox_p(((Const*)other)->constvalue, &search_box) )
{
POSTGIS_DEBUGF(4, " requested search box is: %s", gbox_to_string(&search_box));
/* Get pg_statistic row */
- relid = getrelid(self->varno, root->parse->rtable);
- nd_stats = pg_get_nd_stats(relid, self->varattno, mode);
+ 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! */
-- There are 50000 points in the table with full extent being
-- BOX(0.0439142361 0.0197799355,999.955261 999.993652)
+CREATE TABLE sample_queries AS
+SELECT 1 as id, 5 as tol, 'ST_MakeEnvelope(125,125,135,135)' as box
+ UNION ALL
+SELECT 2, 60, 'ST_MakeEnvelope(0,0,135,135)'
+ UNION ALL
+SELECT 3, 500, 'ST_MakeEnvelope(0,0,500,500)'
+ UNION ALL
+SELECT 4, 600, 'ST_MakeEnvelope(0,0,1000,1000)'
+;
ANALYZE test;
-SELECT estimate_error('
- select num from test where the_geom && ST_MakeEnvelope(125,125,135,135);
-', 5);
+SELECT estimate_error(
+ 'select num from test where the_geom && ' || box, tol )
+ FROM sample_queries ORDER BY id;
-select estimate_error('
- select num from test where the_geom && ST_MakeEnvelope(0,0,135,135);
-', 50);
+-- Test selectivity estimation of functional indexes
-SELECT estimate_error('
- select num from test where the_geom && ST_MakeEnvelope(0,0,500,500);
-', 500);
+CREATE INDEX expressional_gist on test using gist ( st_centroid(the_geom) );
+ANALYZE test;
-SELECT estimate_error('
- select num from test where the_geom && ST_MakeEnvelope(0,0,1000,1000);
-', 600);
+SELECT 'expr', estimate_error(
+ 'select num from test where st_centroid(the_geom) && ' || box, tol )
+ FROM sample_queries ORDER BY id;
DROP TABLE test;
+DROP TABLE sample_queries;
DROP FUNCTION estimate_error(text, int);
projects / postgis / commitdiff