Hi,
When we specify column names for ANALYZE, only the statistics for those columns
are collected. Similarly, is it useful if we have a option to specify an index
for ANALYZE to collect only the statistics for expression in the specified
index?
A usecase I suppose is that when a new expression index is created and that
we need only the statistics for the new index. Although ANALYZE of all the
indexes
is usually fast because ANALYZE uses a random sampling of the table rows,
ANALYZE
on the specific index may be still useful if there are other index whose
"statistics
target" is large and/or whose expression takes time to compute, for example.
Attached is the WIP patch to allow to specify a index name as ANALYZE parameter.
Any documatation is not yet included. I would appreciate any feedback!
Regards,
--
Yugo Nagata <nag...@sraoss.co.jp>
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 25194e8..058f242 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -84,7 +84,7 @@ static BufferAccessStrategy vac_strategy;
static void do_analyze_rel(Relation onerel, int options,
VacuumParams *params, List *va_cols,
AcquireSampleRowsFunc acquirefunc, BlockNumber relpages,
- bool inh, bool in_outer_xact, int elevel);
+ bool inh, bool in_outer_xact, int elevel, Oid indexid);
static void compute_index_stats(Relation onerel, double totalrows,
AnlIndexData *indexdata, int nindexes,
HeapTuple *rows, int numrows,
@@ -121,6 +121,7 @@ analyze_rel(Oid relid, RangeVar *relation, int options,
AcquireSampleRowsFunc acquirefunc = NULL;
BlockNumber relpages = 0;
bool rel_lock = true;
+ Oid indexid = InvalidOid;
/* Select logging level */
if (options & VACOPT_VERBOSE)
@@ -253,6 +254,28 @@ analyze_rel(Oid relid, RangeVar *relation, int options,
/* Also get regular table's size */
relpages = RelationGetNumberOfBlocks(onerel);
}
+ else if (onerel->rd_rel->relkind == RELKIND_INDEX)
+ {
+ Relation rel;
+
+ indexid = relid;
+ relid = IndexGetRelation(indexid, true);
+
+ if (va_cols != NIL)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("ANALYZE option must be specified when a column list is provided")));
+
+ rel = try_relation_open(relid, ShareUpdateExclusiveLock);
+ relation_close(onerel, ShareUpdateExclusiveLock);
+
+ onerel = rel;
+
+ /* Regular table, so we'll use the regular row acquisition function */
+ acquirefunc = acquire_sample_rows;
+ /* Also get regular table's size */
+ relpages = RelationGetNumberOfBlocks(onerel);
+ }
else if (onerel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
{
/*
@@ -308,14 +331,14 @@ analyze_rel(Oid relid, RangeVar *relation, int options,
*/
if (onerel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
do_analyze_rel(onerel, options, params, va_cols, acquirefunc,
- relpages, false, in_outer_xact, elevel);
+ relpages, false, in_outer_xact, elevel, indexid);
/*
* If there are child tables, do recursive ANALYZE.
*/
if (onerel->rd_rel->relhassubclass)
do_analyze_rel(onerel, options, params, va_cols, acquirefunc, relpages,
- true, in_outer_xact, elevel);
+ true, in_outer_xact, elevel, InvalidOid);
/*
* Close source relation now, but keep lock so that no one deletes it
@@ -345,7 +368,7 @@ static void
do_analyze_rel(Relation onerel, int options, VacuumParams *params,
List *va_cols, AcquireSampleRowsFunc acquirefunc,
BlockNumber relpages, bool inh, bool in_outer_xact,
- int elevel)
+ int elevel, Oid indexid)
{
int attr_cnt,
tcnt,
@@ -445,7 +468,7 @@ do_analyze_rel(Relation onerel, int options, VacuumParams *params,
}
attr_cnt = tcnt;
}
- else
+ else if (!OidIsValid(indexid))
{
attr_cnt = onerel->rd_att->natts;
vacattrstats = (VacAttrStats **)
@@ -459,6 +482,8 @@ do_analyze_rel(Relation onerel, int options, VacuumParams *params,
}
attr_cnt = tcnt;
}
+ else
+ attr_cnt = 0;
/*
* Open all indexes of the relation, and see if there are any analyzable
@@ -468,7 +493,7 @@ do_analyze_rel(Relation onerel, int options, VacuumParams *params,
* all.
*/
if (!inh)
- vac_open_indexes(onerel, AccessShareLock, &nindexes, &Irel);
+ vac_open_indexes(onerel, AccessShareLock, &nindexes, &Irel, indexid);
else
{
Irel = NULL;
@@ -750,6 +775,7 @@ compute_index_stats(Relation onerel, double totalrows,
int ind,
i;
+
ind_context = AllocSetContextCreate(anl_context,
"Analyze Index",
ALLOCSET_DEFAULT_SIZES);
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d90cb9a..b21811d 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -1606,7 +1606,7 @@ vacuum_rel(Oid relid, RangeVar *relation, int options, VacuumParams *params)
*/
void
vac_open_indexes(Relation relation, LOCKMODE lockmode,
- int *nindexes, Relation **Irel)
+ int *nindexes, Relation **Irel, Oid idx)
{
List *indexoidlist;
ListCell *indexoidscan;
@@ -1614,7 +1614,10 @@ vac_open_indexes(Relation relation, LOCKMODE lockmode,
Assert(lockmode != NoLock);
- indexoidlist = RelationGetIndexList(relation);
+ if (OidIsValid(idx))
+ indexoidlist = list_make1_oid(idx);
+ else
+ indexoidlist = RelationGetIndexList(relation);
/* allocate enough memory for all indexes */
i = list_length(indexoidlist);
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index 5649a70..40e0a31 100644
--- a/src/backend/commands/vacuumlazy.c
+++ b/src/backend/commands/vacuumlazy.c
@@ -258,7 +258,7 @@ lazy_vacuum_rel(Relation onerel, int options, VacuumParams *params,
vacrelstats->lock_waiter_detected = false;
/* Open all indexes of the relation */
- vac_open_indexes(onerel, RowExclusiveLock, &nindexes, &Irel);
+ vac_open_indexes(onerel, RowExclusiveLock, &nindexes, &Irel, InvalidOid);
vacrelstats->hasindex = (nindexes > 0);
/* Do the vacuuming */
diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h
index 85d472f..00719d5 100644
--- a/src/include/commands/vacuum.h
+++ b/src/include/commands/vacuum.h
@@ -160,7 +160,7 @@ extern void ExecVacuum(VacuumStmt *vacstmt, bool isTopLevel);
extern void vacuum(int options, List *relations, VacuumParams *params,
BufferAccessStrategy bstrategy, bool isTopLevel);
extern void vac_open_indexes(Relation relation, LOCKMODE lockmode,
- int *nindexes, Relation **Irel);
+ int *nindexes, Relation **Irel, Oid idx);
extern void vac_close_indexes(int nindexes, Relation *Irel, LOCKMODE lockmode);
extern double vac_estimate_reltuples(Relation relation,
BlockNumber total_pages,
