On 2021-Apr-08, Tom Lane wrote:
> > So I tend to think that my initial instinct was the better direction: we
> > should not be doing any find_all_inheritors() here at all, but instead
> > rely on pg_class.reltuples to be set for the partitioned table.
>
> +1
This patch does that.
--
Álvaro Herrera 39°49'30"S 73°17'W
"I dream about dreams about dreams", sang the nightingale
under the pale moon (Sandman)
>From a54701552f2ba9295aae4fe0fc22c7bac912bf45 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvhe...@alvh.no-ip.org>
Date: Thu, 8 Apr 2021 11:10:44 -0400
Subject: [PATCH] Set pg_class.reltuples for partitioned tables
---
src/backend/commands/analyze.c | 12 +++++++
src/backend/commands/tablecmds.c | 51 ++++++++++++++++++++++++++++-
src/backend/postmaster/autovacuum.c | 39 +---------------------
3 files changed, 63 insertions(+), 39 deletions(-)
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 5bdaceefd5..2de699d838 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -656,6 +656,18 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
in_outer_xact);
}
}
+ else if (onerel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+ {
+ /*
+ * Partitioned tables don't have storage, so we don't set any fields in
+ * their pg_class entries except for relpages, which is necessary for
+ * auto-analyze to work properly.
+ */
+ vac_update_relstats(onerel, -1, totalrows,
+ 0, false, InvalidTransactionId,
+ InvalidMultiXactId,
+ in_outer_xact);
+ }
/*
* Now report ANALYZE to the stats collector. For regular tables, we do
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1f19629a94..deca860c80 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -337,6 +337,7 @@ typedef struct ForeignTruncateInfo
static void truncate_check_rel(Oid relid, Form_pg_class reltuple);
static void truncate_check_perms(Oid relid, Form_pg_class reltuple);
static void truncate_check_activity(Relation rel);
+static void truncate_update_partedrel_stats(List *parted_rels);
static void RangeVarCallbackForTruncate(const RangeVar *relation,
Oid relId, Oid oldRelId, void *arg);
static List *MergeAttributes(List *schema, List *supers, char relpersistence,
@@ -1755,6 +1756,7 @@ ExecuteTruncateGuts(List *explicit_rels,
{
List *rels;
List *seq_relids = NIL;
+ List *parted_rels = NIL;
HTAB *ft_htab = NULL;
EState *estate;
ResultRelInfo *resultRelInfos;
@@ -1908,9 +1910,15 @@ ExecuteTruncateGuts(List *explicit_rels,
Relation rel = (Relation) lfirst(lc1);
int extra = lfirst_int(lc2);
- /* Skip partitioned tables as there is nothing to do */
+ /*
+ * Save OID of partitioned tables for later; nothing else to do for
+ * them here.
+ */
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+ {
+ parted_rels = lappend_oid(parted_rels, RelationGetRelid(rel));
continue;
+ }
/*
* Build the lists of foreign tables belonging to each foreign server
@@ -2061,6 +2069,9 @@ ExecuteTruncateGuts(List *explicit_rels,
ResetSequence(seq_relid);
}
+ /* Reset partitioned tables' pg_class.reltuples */
+ truncate_update_partedrel_stats(parted_rels);
+
/*
* Write a WAL record to allow this set of actions to be logically
* decoded.
@@ -2207,6 +2218,44 @@ truncate_check_activity(Relation rel)
CheckTableNotInUse(rel, "TRUNCATE");
}
+/*
+ * Update pg_class.reltuples for all the given partitioned tables to 0.
+ */
+static void
+truncate_update_partedrel_stats(List *parted_rels)
+{
+ Relation pg_class;
+ HeapTuple tuple;
+ Form_pg_class rd_rel;
+ ListCell *lc;
+
+ pg_class = table_open(RelationRelationId, RowExclusiveLock);
+
+ foreach(lc, parted_rels)
+ {
+ Oid relid = lfirst_oid(lc);
+ bool dirty = false;
+
+ tuple = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(tuple))
+ elog(ERROR, "could not find tuple for relation %u", relid);
+ rd_rel = (Form_pg_class) GETSTRUCT(tuple);
+
+ if (rd_rel->reltuples != 0)
+ {
+ rd_rel->reltuples = (float4) 0;
+ dirty = true;
+ }
+
+ if (dirty)
+ heap_inplace_update(pg_class, tuple);
+
+ heap_freetuple(tuple);
+ }
+
+ table_close(pg_class, RowExclusiveLock);
+}
+
/*
* storage_name
* returns the name corresponding to a typstorage/attstorage enum value
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index aef9ac4dd2..a799544738 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -3209,44 +3209,7 @@ relation_needs_vacanalyze(Oid relid,
*/
if (PointerIsValid(tabentry) && AutoVacuumingActive())
{
- if (classForm->relkind != RELKIND_PARTITIONED_TABLE)
- {
- reltuples = classForm->reltuples;
- }
- else
- {
- /*
- * If the relation is a partitioned table, we must add up
- * children's reltuples.
- */
- List *children;
- ListCell *lc;
-
- reltuples = 0;
-
- /* Find all members of inheritance set taking AccessShareLock */
- children = find_all_inheritors(relid, AccessShareLock, NULL);
-
- foreach(lc, children)
- {
- Oid childOID = lfirst_oid(lc);
- HeapTuple childtuple;
- Form_pg_class childclass;
-
- childtuple = SearchSysCache1(RELOID, ObjectIdGetDatum(childOID));
- childclass = (Form_pg_class) GETSTRUCT(childtuple);
-
- /* Skip a partitioned table and foreign partitions */
- if (RELKIND_HAS_STORAGE(childclass->relkind))
- {
- /* Sum up the child's reltuples for its parent table */
- reltuples += childclass->reltuples;
- }
- ReleaseSysCache(childtuple);
- }
-
- list_free(children);
- }
+ reltuples = classForm->reltuples;
vactuples = tabentry->n_dead_tuples;
instuples = tabentry->inserts_since_vacuum;
anltuples = tabentry->changes_since_analyze;
--
2.20.1
