open-dsi
/
postgres
mirror of https://github.com/postgres/postgres
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add hooks to let plugins override the planner's lookups in pg_statistic.

Browse Source 
Simon Riggs, with some editorialization by me.
REL8_5_ALPHA1_BRANCH
Tom Lane 17 years ago
parent bc965e840a
commit 7b7df9f0b1
4 changed files with 109 additions and 23 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 85
      src/backend/utils/adt/selfuncs.c
  2. 22
      src/backend/utils/cache/lsyscache.c
  3. 6
      src/include/utils/lsyscache.h
  4. 19
      src/include/utils/selfuncs.h

85
src/backend/utils/adt/selfuncs.c
Unescape View File

@ -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();
}

22
src/backend/utils/cache/lsyscache.c vendored
Unescape View File

@ -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).

6
src/include/utils/lsyscache.h
Unescape View File

@ -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,

19
src/include/utils/selfuncs.h
Unescape View File

@ -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,

Write Preview
Loading…
Cancel
Save