diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 7524e2d5809b0e2a78fa9755a0f207d9cc99c194..e2336ea4f21c0cacccb10b29b7e8f8265037f854 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -15,7 +15,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.253 2008/08/25 22:42:34 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.254 2008/09/28 19:51:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -119,6 +119,10 @@
#include "utils/syscache.h"
+/* Hooks for plugins to get control when we ask for stats */
+get_relation_stats_hook_type get_relation_stats_hook = NULL;
+get_index_stats_hook_type get_index_stats_hook = NULL;
+
static double var_eq_const(VariableStatData *vardata, Oid operator,
Datum constval, bool constisnull,
bool varonleft);
@@ -2935,7 +2939,7 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows)
* complicated.
*/
examine_variable(root, groupexpr, 0, &vardata);
- if (vardata.statsTuple != NULL || vardata.isunique)
+ if (HeapTupleIsValid(vardata.statsTuple) || vardata.isunique)
{
varinfos = add_unique_group_var(root, varinfos,
groupexpr, &vardata);
@@ -3942,6 +3946,7 @@ get_join_variables(PlannerInfo *root, List *args, SpecialJoinInfo *sjinfo,
* subquery, not one in the current query).
* statsTuple: the pg_statistic entry for the variable, if one exists;
* otherwise NULL.
+ * freefunc: pointer to a function to release statsTuple with.
* vartype: exposed type of the expression; this should always match
* the declared input type of the operator we are estimating for.
* atttype, atttypmod: type data to pass to get_attstatsslot(). This is
@@ -3986,7 +3991,18 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
rte = root->simple_rte_array[var->varno];
- if (rte->inh)
+ if (get_relation_stats_hook &&
+ (*get_relation_stats_hook) (root, rte, var->varattno, vardata))
+ {
+ /*
+ * The hook took control of acquiring a stats tuple. If it
+ * did supply a tuple, it'd better have supplied a freefunc.
+ */
+ if (HeapTupleIsValid(vardata->statsTuple) &&
+ !vardata->freefunc)
+ elog(ERROR, "no function provided to release variable stats with");
+ }
+ else if (rte->inh)
{
/*
* XXX This means the Var represents a column of an append
@@ -4000,6 +4016,7 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
ObjectIdGetDatum(rte->relid),
Int16GetDatum(var->varattno),
0, 0);
+ vardata->freefunc = ReleaseSysCache;
}
else
{
@@ -4116,10 +4133,28 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
index->indpred == NIL)
vardata->isunique = true;
/* Has it got stats? */
- vardata->statsTuple = SearchSysCache(STATRELATT,
- ObjectIdGetDatum(index->indexoid),
- Int16GetDatum(pos + 1),
- 0, 0);
+ if (get_index_stats_hook &&
+ (*get_index_stats_hook) (root, index->indexoid,
+ pos + 1, vardata))
+ {
+ /*
+ * The hook took control of acquiring a stats
+ * tuple. If it did supply a tuple, it'd better
+ * have supplied a freefunc.
+ */
+ if (HeapTupleIsValid(vardata->statsTuple) &&
+ !vardata->freefunc)
+ elog(ERROR, "no function provided to release variable stats with");
+ }
+ else
+ {
+ vardata->statsTuple =
+ SearchSysCache(STATRELATT,
+ ObjectIdGetDatum(index->indexoid),
+ Int16GetDatum(pos + 1),
+ 0, 0);
+ vardata->freefunc = ReleaseSysCache;
+ }
if (vardata->statsTuple)
break;
}
@@ -5551,7 +5586,7 @@ btcostestimate(PG_FUNCTION_ARGS)
double *indexCorrelation = (double *) PG_GETARG_POINTER(7);
Oid relid;
AttrNumber colnum;
- HeapTuple tuple;
+ VariableStatData vardata;
double numIndexTuples;
List *indexBoundQuals;
int indexcol;
@@ -5756,17 +5791,34 @@ btcostestimate(PG_FUNCTION_ARGS)
colnum = 1;
}
- tuple = SearchSysCache(STATRELATT,
- ObjectIdGetDatum(relid),
- Int16GetDatum(colnum),
- 0, 0);
+ MemSet(&vardata, 0, sizeof(vardata));
- if (HeapTupleIsValid(tuple))
+ if (get_index_stats_hook &&
+ (*get_index_stats_hook) (root, relid, colnum, &vardata))
+ {
+ /*
+ * The hook took control of acquiring a stats tuple. If it did supply
+ * a tuple, it'd better have supplied a freefunc.
+ */
+ if (HeapTupleIsValid(vardata.statsTuple) &&
+ !vardata.freefunc)
+ elog(ERROR, "no function provided to release variable stats with");
+ }
+ else
+ {
+ vardata.statsTuple = SearchSysCache(STATRELATT,
+ ObjectIdGetDatum(relid),
+ Int16GetDatum(colnum),
+ 0, 0);
+ vardata.freefunc = ReleaseSysCache;
+ }
+
+ if (HeapTupleIsValid(vardata.statsTuple))
{
float4 *numbers;
int nnumbers;
- if (get_attstatsslot(tuple, InvalidOid, 0,
+ if (get_attstatsslot(vardata.statsTuple, InvalidOid, 0,
STATISTIC_KIND_CORRELATION,
index->fwdsortop[0],
NULL, NULL, &numbers, &nnumbers))
@@ -5783,7 +5835,7 @@ btcostestimate(PG_FUNCTION_ARGS)
free_attstatsslot(InvalidOid, NULL, 0, numbers, nnumbers);
}
- else if (get_attstatsslot(tuple, InvalidOid, 0,
+ else if (get_attstatsslot(vardata.statsTuple, InvalidOid, 0,
STATISTIC_KIND_CORRELATION,
index->revsortop[0],
NULL, NULL, &numbers, &nnumbers))
@@ -5800,9 +5852,10 @@ btcostestimate(PG_FUNCTION_ARGS)
free_attstatsslot(InvalidOid, NULL, 0, numbers, nnumbers);
}
- ReleaseSysCache(tuple);
}
+ ReleaseVariableStats(vardata);
+
PG_RETURN_VOID();
}
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index ed94af6d494e963dafeb625be7ed731ef673528a..60ec8e5894106af45aa876a36166794b5c82c617 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.159 2008/08/02 21:32:00 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.160 2008/09/28 19:51:40 tgl Exp $
*
* NOTES
* Eventually, the index information should go through here, too.
@@ -35,6 +35,9 @@
#include "utils/lsyscache.h"
#include "utils/syscache.h"
+/* Hook for plugins to get control in get_attavgwidth() */
+get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
+
/* ---------- AMOP CACHES ---------- */
@@ -2492,20 +2495,30 @@ get_typmodout(Oid typid)
*
* Given the table and attribute number of a column, get the average
* width of entries in the column. Return zero if no data available.
+ *
+ * Calling a hook at this point looks somewhat strange, but is required
+ * because the optimizer calls this function without any other way for
+ * plug-ins to control the result.
*/
int32
get_attavgwidth(Oid relid, AttrNumber attnum)
{
HeapTuple tp;
+ int32 stawidth;
+ if (get_attavgwidth_hook)
+ {
+ stawidth = (*get_attavgwidth_hook) (relid, attnum);
+ if (stawidth > 0)
+ return stawidth;
+ }
tp = SearchSysCache(STATRELATT,
ObjectIdGetDatum(relid),
Int16GetDatum(attnum),
0, 0);
if (HeapTupleIsValid(tp))
{
- int32 stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
-
+ stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
ReleaseSysCache(tp);
if (stawidth > 0)
return stawidth;
@@ -2523,6 +2536,9 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
* already-looked-up tuple in the pg_statistic cache. We do this since
* most callers will want to extract more than one value from the cache
* entry, and we don't want to repeat the cache lookup unnecessarily.
+ * Also, this API allows this routine to be used with statistics tuples
+ * that have been provided by a stats hook and didn't really come from
+ * pg_statistic.
*
* statstuple: pg_statistics tuple to be examined.
* atttype: type OID of attribute (can be InvalidOid if values == NULL).
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index 0538e0ff56989ff2904d4ce34079239785eff41f..48ecd276c7390883458171fa2ece84f769197838 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.125 2008/08/02 21:32:01 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.126 2008/09/28 19:51:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -26,6 +26,10 @@ typedef enum IOFuncSelector
IOFunc_send
} IOFuncSelector;
+/* Hook for plugins to get control in get_attavgwidth() */
+typedef int32 (*get_attavgwidth_hook_type) (Oid relid, AttrNumber attnum);
+extern PGDLLIMPORT get_attavgwidth_hook_type get_attavgwidth_hook;
+
extern bool op_in_opfamily(Oid opno, Oid opfamily);
extern int get_op_opfamily_strategy(Oid opno, Oid opfamily);
extern void get_op_opfamily_properties(Oid opno, Oid opfamily,
diff --git a/src/include/utils/selfuncs.h b/src/include/utils/selfuncs.h
index 120269eee5dcf6a8b8a4c7499d37a136487218fb..74ee9cd197eba6f0899d2812a970fa2e08b500ae 100644
--- a/src/include/utils/selfuncs.h
+++ b/src/include/utils/selfuncs.h
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.46 2008/08/16 00:01:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.47 2008/09/28 19:51:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -64,12 +64,13 @@
/* Return data from examine_variable and friends */
-typedef struct
+typedef struct VariableStatData
{
Node *var; /* the Var or expression tree */
RelOptInfo *rel; /* Relation, or NULL if not identifiable */
HeapTuple statsTuple; /* pg_statistic tuple, or NULL if none */
/* NB: if statsTuple!=NULL, it must be freed when caller is done */
+ void (*freefunc) (HeapTuple tuple); /* how to free statsTuple */
Oid vartype; /* exposed type of expression */
Oid atttype; /* type to pass to get_attstatsslot */
int32 atttypmod; /* typmod to pass to get_attstatsslot */
@@ -79,7 +80,7 @@ typedef struct
#define ReleaseVariableStats(vardata) \
do { \
if (HeapTupleIsValid((vardata).statsTuple)) \
- ReleaseSysCache((vardata).statsTuple); \
+ (* (vardata).freefunc) ((vardata).statsTuple); \
} while(0)
@@ -97,6 +98,18 @@ typedef enum
/* selfuncs.c */
+/* Hooks for plugins to get control when we ask for stats */
+typedef bool (*get_relation_stats_hook_type) (PlannerInfo *root,
+ RangeTblEntry *rte,
+ AttrNumber attnum,
+ VariableStatData *vardata);
+extern PGDLLIMPORT get_relation_stats_hook_type get_relation_stats_hook;
+typedef bool (*get_index_stats_hook_type) (PlannerInfo *root,
+ Oid indexOid,
+ AttrNumber indexattnum,
+ VariableStatData *vardata);
+extern PGDLLIMPORT get_index_stats_hook_type get_index_stats_hook;
+
extern void examine_variable(PlannerInfo *root, Node *node, int varRelid,
VariableStatData *vardata);
extern bool get_restriction_variable(PlannerInfo *root, List *args,