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help / color / mirror / Atom feedFrom: Bertrand Drouvot <[email protected]>
Subject: [PATCH v14 2/2] handle relation statistics correctly during rewrites
Date: Tue, 4 Nov 2025 13:52:46 +0000
Now that PGSTAT_KIND_RELATION is keyed by refilenode, we need to handle rewrites.
To do so, this patch:
- Adds PgStat_PendingRewrite, a new struct to track rewrite operations within
a transaction, storing the old locator, new locator, and original locator (for
rewrite chains). This allows stats to be copied from the original location to
the final location at commit time.
- Adds a new function, pgstat_mark_rewrite(), called when a table rewrite begins.
It records the rewrite operation in a local list and detects rewrite chains by
checking if the old_locator matches any existing new_locator, preserving the
chain's original_locator.
- Modifies pgstat_copy_relation_stats(), to accept RelFileLocators instead of
Relations, with a new increment parameter to accumulate stats (needed for rewrite
chains with DML between rewrites).
- Ensures that AtEOXact_PgStat_Relations(), AtPrepare_PgStat_Relations(),
pgstat_twophase_postcommit()/postabort() pgstat_drop_relation() handle the
PgStat_PendingRewrite list correctly.
Note that due to the new flush call in pgstat_twophase_postcommit() we can not
call GetCurrentTransactionStopTimestamp() in pgstat_relation_flush_cb(). So,
adding a check to handle this special case and call GetCurrentTimestamp() instead.
Note that we'd call GetCurrentTimestamp() only if there is a rewrite, so that
the GetCurrentTimestamp() extra cost should be negligible. Another solution
could be to trigger the flush from FinishPreparedTransaction() but that's not
worth the extra complexity.
The new pending_rewrites list is traversed in multiple places. The overhead
should be negligible in comparison to a rewrite and the list should not contain
a lot of rewrites in practice.
The pending_rewrites list is traversed in multiple places. In typical usage,
the list will contain only a few entries so the traversal cost is negligible (
furthermore in comparison to a rewrite).
---
src/backend/catalog/index.c | 2 +-
src/backend/commands/cluster.c | 5 +
src/backend/commands/tablecmds.c | 6 +
src/backend/utils/activity/pgstat_relation.c | 391 ++++++++++++++++++-
src/backend/utils/activity/pgstat_xact.c | 25 +-
src/backend/utils/cache/relcache.c | 6 +
src/include/pgstat.h | 5 +-
src/tools/pgindent/typedefs.list | 1 +
8 files changed, 424 insertions(+), 17 deletions(-)
92.8% src/backend/utils/activity/
4.9% src/backend/
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index d8219b18c48..079e504b96f 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1796,7 +1796,7 @@ index_concurrently_swap(Oid newIndexId, Oid oldIndexId, const char *oldName)
changeDependenciesOn(RelationRelationId, oldIndexId, newIndexId);
/* copy over statistics from old to new index */
- pgstat_copy_relation_stats(newClassRel, oldClassRel);
+ pgstat_copy_relation_stats(newClassRel->rd_locator, oldClassRel->rd_locator, false);
/* Copy data of pg_statistic from the old index to the new one */
CopyStatistics(oldIndexId, newIndexId);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 09066db0956..c491daceb0f 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1206,6 +1206,11 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
rel1 = relation_open(r1, NoLock);
rel2 = relation_open(r2, NoLock);
+
+ /* Mark that a rewrite happened */
+ if (RELKIND_HAS_STORAGE(rel1->rd_rel->relkind))
+ pgstat_mark_rewrite(rel1->rd_locator, rel2->rd_locator);
+
rel2->rd_createSubid = rel1->rd_createSubid;
rel2->rd_newRelfilelocatorSubid = rel1->rd_newRelfilelocatorSubid;
rel2->rd_firstRelfilelocatorSubid = rel1->rd_firstRelfilelocatorSubid;
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index c69c12dc014..13630846116 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -17099,6 +17099,7 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
Oid reltoastrelid;
RelFileNumber newrelfilenumber;
RelFileLocator newrlocator;
+ RelFileLocator oldrlocator;
List *reltoastidxids = NIL;
ListCell *lc;
@@ -17137,6 +17138,7 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
newrlocator = rel->rd_locator;
newrlocator.relNumber = newrelfilenumber;
newrlocator.spcOid = newTableSpace;
+ oldrlocator = rel->rd_locator;
/* hand off to AM to actually create new rel storage and copy the data */
if (rel->rd_rel->relkind == RELKIND_INDEX)
@@ -17149,6 +17151,10 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
table_relation_copy_data(rel, &newrlocator);
}
+ /* mark that a rewrite happened */
+ if (RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
+ pgstat_mark_rewrite(oldrlocator, newrlocator);
+
/*
* Update the pg_class row.
*
diff --git a/src/backend/utils/activity/pgstat_relation.c b/src/backend/utils/activity/pgstat_relation.c
index 89bf0cbed56..4d929972fab 100644
--- a/src/backend/utils/activity/pgstat_relation.c
+++ b/src/backend/utils/activity/pgstat_relation.c
@@ -30,6 +30,19 @@
#include "utils/syscache.h"
#include "utils/timestamp.h"
+/* Pending rewrite operations for stats copying */
+typedef struct PgStat_PendingRewrite
+{
+ RelFileLocator old_locator;
+ RelFileLocator new_locator;
+ RelFileLocator original_locator;
+ int nest_level; /* Transaction nesting level where rewrite
+ * occurred */
+ struct PgStat_PendingRewrite *next;
+} PgStat_PendingRewrite;
+
+/* The pending rewrites list for current transaction */
+static PgStat_PendingRewrite *pending_rewrites = NULL;
/* Record that's written to 2PC state file when pgstat state is persisted */
typedef struct TwoPhasePgStatRecord
@@ -43,6 +56,8 @@ typedef struct TwoPhasePgStatRecord
PgStat_Counter deleted_pre_truncdrop;
RelFileLocator locator; /* table's rd_locator */
bool truncdropped; /* was the relation truncated/dropped? */
+ RelFileLocator rewrite_old_locator;
+ int rewrite_nest_level;
} TwoPhasePgStatRecord;
@@ -54,27 +69,70 @@ static void restore_truncdrop_counters(PgStat_TableXactStatus *trans);
/*
- * Copy stats between relations. This is used for things like REINDEX
+ * Copy stats between RelFileLocator. This is used for things like REINDEX
* CONCURRENTLY.
*/
void
-pgstat_copy_relation_stats(Relation dst, Relation src)
+pgstat_copy_relation_stats(RelFileLocator dst, RelFileLocator src, bool increment)
{
PgStat_StatTabEntry *srcstats;
PgStatShared_Relation *dstshstats;
PgStat_EntryRef *dst_ref;
- srcstats = pgstat_fetch_stat_tabentry_ext(RelationGetRelid(src));
+ srcstats = (PgStat_StatTabEntry *) pgstat_fetch_entry(PGSTAT_KIND_RELATION,
+ src.dbOid,
+ RelFileLocatorToPgStatObjid(src));
if (!srcstats)
return;
dst_ref = pgstat_get_entry_ref_locked(PGSTAT_KIND_RELATION,
- dst->rd_rel->relisshared ? InvalidOid : MyDatabaseId,
- RelationGetRelid(dst),
+ dst.dbOid,
+ RelFileLocatorToPgStatObjid(dst),
false);
dstshstats = (PgStatShared_Relation *) dst_ref->shared_stats;
- dstshstats->stats = *srcstats;
+
+ if (!increment)
+ dstshstats->stats = *srcstats;
+ else
+ {
+ /* Increment those statistics */
+#define RELFSTAT_ACC(fld, stats_to_add) \
+ (dstshstats->stats.fld += stats_to_add->fld)
+ RELFSTAT_ACC(numscans, srcstats);
+ RELFSTAT_ACC(tuples_returned, srcstats);
+ RELFSTAT_ACC(tuples_fetched, srcstats);
+ RELFSTAT_ACC(tuples_inserted, srcstats);
+ RELFSTAT_ACC(tuples_updated, srcstats);
+ RELFSTAT_ACC(tuples_deleted, srcstats);
+ RELFSTAT_ACC(tuples_hot_updated, srcstats);
+ RELFSTAT_ACC(tuples_newpage_updated, srcstats);
+ RELFSTAT_ACC(live_tuples, srcstats);
+ RELFSTAT_ACC(dead_tuples, srcstats);
+ RELFSTAT_ACC(mod_since_analyze, srcstats);
+ RELFSTAT_ACC(ins_since_vacuum, srcstats);
+ RELFSTAT_ACC(blocks_fetched, srcstats);
+ RELFSTAT_ACC(blocks_hit, srcstats);
+ RELFSTAT_ACC(vacuum_count, srcstats);
+ RELFSTAT_ACC(autovacuum_count, srcstats);
+ RELFSTAT_ACC(analyze_count, srcstats);
+ RELFSTAT_ACC(autoanalyze_count, srcstats);
+ RELFSTAT_ACC(total_vacuum_time, srcstats);
+ RELFSTAT_ACC(total_autovacuum_time, srcstats);
+ RELFSTAT_ACC(total_analyze_time, srcstats);
+ RELFSTAT_ACC(total_autoanalyze_time, srcstats);
+#undef RELFSTAT_ACC
+
+ /* Replace those statistics */
+#define RELFSTAT_REP(fld, stats_to_rep) \
+ (dstshstats->stats.fld = stats_to_rep->fld)
+ RELFSTAT_REP(lastscan, srcstats);
+ RELFSTAT_REP(last_vacuum_time, srcstats);
+ RELFSTAT_REP(last_autovacuum_time, srcstats);
+ RELFSTAT_REP(last_analyze_time, srcstats);
+ RELFSTAT_REP(last_autoanalyze_time, srcstats);
+#undef RELFSTAT_REP
+ }
pgstat_unlock_entry(dst_ref);
}
@@ -136,6 +194,7 @@ void
pgstat_assoc_relation(Relation rel)
{
RelFileLocator locator;
+ PgStat_TableStatus *pgstat_info;
Assert(rel->pgstat_enabled);
Assert(rel->pgstat_info == NULL);
@@ -164,14 +223,54 @@ pgstat_assoc_relation(Relation rel)
locator.relNumber = rel->rd_id;
}
+ /*
+ * If this relation was rewritten during the current transaction we may be
+ * reopening it with its new RelFileLocator. In that case, continue using
+ * the stats entry associated with the old locator rather than creating a
+ * new one. This ensures all stats from before and after the rewrite are
+ * tracked in a single entry which will be properly copied to the new
+ * locator at transaction commit.
+ */
+ if (pending_rewrites != NULL)
+ {
+ PgStat_PendingRewrite *rewrite;
+
+ for (rewrite = pending_rewrites; rewrite != NULL; rewrite = rewrite->next)
+ {
+ if (locator.dbOid == rewrite->new_locator.dbOid &&
+ locator.spcOid == rewrite->new_locator.spcOid &&
+ locator.relNumber == rewrite->new_locator.relNumber)
+ {
+ pgstat_info = pgstat_prep_relation_pending(rewrite->old_locator);
+ goto found_entry;
+ }
+ }
+ }
+
/* Else find or make the PgStat_TableStatus entry, and update link */
- rel->pgstat_info = pgstat_prep_relation_pending(locator);
+ pgstat_info = pgstat_prep_relation_pending(locator);
+
+found_entry:
+ rel->pgstat_info = pgstat_info;
+
+ /*
+ * For relations stats, we key by physical file location, not by relation
+ * OID. This means during operations like ALTER TYPE it's possible that
+ * the relation OID changes but the relfilenode stays the same (no actual
+ * rewrite needed). Unlink the old relation first.
+ */
+ if (pgstat_info->relation != NULL &&
+ pgstat_info->relation != rel)
+ {
+ pgstat_info->relation->pgstat_info = NULL;
+ pgstat_info->relation = NULL;
+ }
/* don't allow link a stats to multiple relcache entries */
- Assert(rel->pgstat_info->relation == NULL);
+ Assert(pgstat_info->relation == NULL);
/* mark this relation as the owner */
- rel->pgstat_info->relation = rel;
+ pgstat_info->relation = rel;
}
/*
@@ -214,14 +313,37 @@ pgstat_drop_relation(Relation rel)
{
int nest_level = GetCurrentTransactionNestLevel();
PgStat_TableStatus *pgstat_info;
+ bool skip_transactional_drop = false;
/* don't track stats for relations without storage */
if (!RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
return;
- pgstat_drop_transactional(PGSTAT_KIND_RELATION,
- rel->rd_locator.dbOid,
- RelFileLocatorToPgStatObjid(rel->rd_locator));
+ /* Check if this drop is part of a pending rewrite */
+ if (pending_rewrites != NULL)
+ {
+ PgStat_PendingRewrite *rewrite;
+
+ for (rewrite = pending_rewrites; rewrite != NULL; rewrite = rewrite->next)
+ {
+ if (rel->rd_locator.dbOid == rewrite->old_locator.dbOid &&
+ rel->rd_locator.spcOid == rewrite->old_locator.spcOid &&
+ rel->rd_locator.relNumber == rewrite->old_locator.relNumber)
+ {
+ skip_transactional_drop = true;
+ break;
+ }
+ }
+ }
+
+ /*
+ * If it is part of a rewrite, drop its stats later, for example in
+ * AtEOXact_PgStat_Relations(), so skip it here.
+ */
+ if (!skip_transactional_drop)
+ pgstat_drop_transactional(PGSTAT_KIND_RELATION,
+ rel->rd_locator.dbOid,
+ RelFileLocatorToPgStatObjid(rel->rd_locator));
if (!pgstat_should_count_relation(rel))
return;
@@ -666,6 +788,48 @@ AtEOXact_PgStat_Relations(PgStat_SubXactStatus *xact_state, bool isCommit)
}
tabstat->trans = NULL;
}
+
+ /* preserve the stats in case of rewrite */
+ if (isCommit && pending_rewrites != NULL)
+ {
+ PgStat_PendingRewrite *rewrite;
+ PgStat_PendingRewrite *prev = NULL;
+ PgStat_PendingRewrite *current = pending_rewrites;
+ PgStat_PendingRewrite *next;
+
+ /* reverse the rewrites list to process in chronological order */
+ while (current != NULL)
+ {
+ next = current->next;
+ current->next = prev;
+ prev = current;
+ current = next;
+ }
+
+ /* now process rewrites in chronological order */
+ for (rewrite = prev; rewrite != NULL; rewrite = rewrite->next)
+ {
+ PgStat_EntryRef *old_entry_ref;
+
+ old_entry_ref = pgstat_fetch_pending_entry(PGSTAT_KIND_RELATION,
+ rewrite->old_locator.dbOid,
+ RelFileLocatorToPgStatObjid(rewrite->old_locator));
+
+ if (old_entry_ref && old_entry_ref->pending)
+ pgstat_relation_flush_cb(old_entry_ref, false);
+
+ pgstat_copy_relation_stats(rewrite->new_locator,
+ rewrite->old_locator, true);
+
+ /* drop old locator's stats */
+ if (!pgstat_drop_entry(PGSTAT_KIND_RELATION,
+ rewrite->old_locator.dbOid,
+ RelFileLocatorToPgStatObjid(rewrite->old_locator)))
+ pgstat_request_entry_refs_gc();
+ }
+ }
+
+ pending_rewrites = NULL;
}
/*
@@ -681,6 +845,30 @@ AtEOSubXact_PgStat_Relations(PgStat_SubXactStatus *xact_state, bool isCommit, in
PgStat_TableXactStatus *trans;
PgStat_TableXactStatus *next_trans;
+ /*
+ * If we don't commit then remove the associated rewrites if any, to keep
+ * the rewrite chain in sync with what will be eventually committed.
+ */
+ if (!isCommit)
+ {
+ PgStat_PendingRewrite **rewrite_ptr = &pending_rewrites;
+
+ while (*rewrite_ptr != NULL)
+ {
+ if ((*rewrite_ptr)->nest_level >= nestDepth)
+ {
+ PgStat_PendingRewrite *to_remove = *rewrite_ptr;
+
+ *rewrite_ptr = (*rewrite_ptr)->next;
+ pfree(to_remove);
+ }
+ else
+ {
+ rewrite_ptr = &((*rewrite_ptr)->next);
+ }
+ }
+ }
+
for (trans = xact_state->first; trans != NULL; trans = next_trans)
{
PgStat_TableStatus *tabstat;
@@ -760,11 +948,19 @@ void
AtPrepare_PgStat_Relations(PgStat_SubXactStatus *xact_state)
{
PgStat_TableXactStatus *trans;
+ PgStat_PendingRewrite *rewrite;
+ /*
+ * For each tabstat, find its matching rewrite and remove it from the
+ * pending rewrites list. This way, after processing all tabstats, pending
+ * rewrites will only contain rewrite only transactions.
+ */
for (trans = xact_state->first; trans != NULL; trans = trans->next)
{
PgStat_TableStatus *tabstat PG_USED_FOR_ASSERTS_ONLY;
TwoPhasePgStatRecord record;
+ PgStat_PendingRewrite **rewrite_ptr;
+ bool found_rewrite = false;
Assert(trans->nest_level == 1);
Assert(trans->upper == NULL);
@@ -784,10 +980,83 @@ AtPrepare_PgStat_Relations(PgStat_SubXactStatus *xact_state)
record.locator = tabstat->locator;
record.truncdropped = trans->truncdropped;
+ record.rewrite_nest_level = 0;
+
+ /*
+ * Look for a matching rewrite and remove it from pending rewrites. We
+ * check three possible matches:
+ *
+ * The new_locator when stats have been added after the rewrite. The
+ * old_locator when stats have been added before the rewrite but not
+ * after. The original_locator when this tabstat is part of a rewrite
+ * chain.
+ */
+ rewrite_ptr = &pending_rewrites;
+ while (*rewrite_ptr != NULL)
+ {
+ rewrite = *rewrite_ptr;
+
+ if ((record.locator.dbOid == rewrite->new_locator.dbOid &&
+ record.locator.spcOid == rewrite->new_locator.spcOid &&
+ record.locator.relNumber == rewrite->new_locator.relNumber) ||
+ (tabstat->locator.dbOid == rewrite->old_locator.dbOid &&
+ tabstat->locator.spcOid == rewrite->old_locator.spcOid &&
+ tabstat->locator.relNumber == rewrite->old_locator.relNumber) ||
+ (tabstat->locator.dbOid == rewrite->original_locator.dbOid &&
+ tabstat->locator.spcOid == rewrite->original_locator.spcOid &&
+ tabstat->locator.relNumber == rewrite->original_locator.relNumber))
+ {
+ /*
+ * Found matching rewrite. Record the rewrite information and
+ * remove this rewrite from the list since it's now handled.
+ */
+ record.rewrite_old_locator = rewrite->original_locator;
+ record.rewrite_nest_level = rewrite->nest_level;
+ record.locator = rewrite->new_locator;
+ found_rewrite = true;
+
+ /* Remove from pending_rewrites list */
+ *rewrite_ptr = rewrite->next;
+ pfree(rewrite);
+ break;
+ }
+ else
+ {
+ /* Move to next rewrite in the list */
+ rewrite_ptr = &(rewrite->next);
+ }
+ }
+
+ /* If no rewrite found, clear the rewrite fields */
+ if (!found_rewrite)
+ {
+ memset(&record.rewrite_old_locator, 0, sizeof(RelFileLocator));
+ }
+
+ RegisterTwoPhaseRecord(TWOPHASE_RM_PGSTAT_ID, 0,
+ &record, sizeof(TwoPhasePgStatRecord));
+ }
+
+ /*
+ * Now process any rewrites still pending. These are rewrite only
+ * transactions. We need to preserve their stats even though there's no
+ * tabstat entry for them.
+ */
+ for (rewrite = pending_rewrites; rewrite != NULL; rewrite = rewrite->next)
+ {
+ TwoPhasePgStatRecord record;
+
+ memset(&record, 0, sizeof(TwoPhasePgStatRecord));
+ record.locator = rewrite->new_locator;
+ record.rewrite_old_locator = rewrite->original_locator;
+ record.rewrite_nest_level = rewrite->nest_level;
+ record.truncdropped = false;
RegisterTwoPhaseRecord(TWOPHASE_RM_PGSTAT_ID, 0,
&record, sizeof(TwoPhasePgStatRecord));
}
+
+ pending_rewrites = NULL;
}
/*
@@ -810,6 +1079,8 @@ PostPrepare_PgStat_Relations(PgStat_SubXactStatus *xact_state)
tabstat = trans->parent;
tabstat->trans = NULL;
}
+
+ pending_rewrites = NULL;
}
/*
@@ -845,6 +1116,29 @@ pgstat_twophase_postcommit(FullTransactionId fxid, uint16 info,
pgstat_info->counts.changed_tuples +=
rec->tuples_inserted + rec->tuples_updated +
rec->tuples_deleted;
+
+ if (rec->rewrite_nest_level > 0)
+ {
+ PgStat_EntryRef *old_entry_ref;
+
+ /* Flush any pending stats for old locator first */
+ old_entry_ref = pgstat_fetch_pending_entry(PGSTAT_KIND_RELATION,
+ rec->rewrite_old_locator.dbOid,
+ RelFileLocatorToPgStatObjid(rec->rewrite_old_locator));
+
+ if (old_entry_ref && old_entry_ref->pending)
+ pgstat_relation_flush_cb(old_entry_ref, false);
+
+ /* Copy stats from old to new locator */
+ pgstat_copy_relation_stats(rec->locator, rec->rewrite_old_locator,
+ true);
+
+ /* Drop old locator's stats */
+ if (!pgstat_drop_entry(PGSTAT_KIND_RELATION,
+ rec->rewrite_old_locator.dbOid,
+ RelFileLocatorToPgStatObjid(rec->rewrite_old_locator)))
+ pgstat_request_entry_refs_gc();
+ }
}
/*
@@ -859,9 +1153,26 @@ pgstat_twophase_postabort(FullTransactionId fxid, uint16 info,
{
TwoPhasePgStatRecord *rec = (TwoPhasePgStatRecord *) recdata;
PgStat_TableStatus *pgstat_info;
+ RelFileLocator target_locator;
+
+ /*
+ * For aborted transactions with rewrites (like TRUNCATE), we need to
+ * restore stats to the old locator, not the new one. The new locator
+ * should be dropped since the rewrite is being rolled back.
+ */
+ if (rec->rewrite_nest_level > 0)
+ {
+ /* Use the old locator */
+ target_locator = rec->rewrite_old_locator;
+ }
+ else
+ {
+ /* No rewrite, use the original locator */
+ target_locator = rec->locator;
+ }
/* Find or create a tabstat entry for the target locator */
- pgstat_info = pgstat_prep_relation_pending(rec->locator);
+ pgstat_info = pgstat_prep_relation_pending(target_locator);
/* Same math as in AtEOXact_PgStat, abort case */
if (rec->truncdropped)
@@ -916,7 +1227,17 @@ pgstat_relation_flush_cb(PgStat_EntryRef *entry_ref, bool nowait)
tabentry->numscans += lstats->counts.numscans;
if (lstats->counts.numscans)
{
- TimestampTz t = GetCurrentTransactionStopTimestamp();
+ TimestampTz t;
+
+ /*
+ * Checking the transaction state due to the flush call in
+ * pgstat_twophase_postcommit() that would break the assertion on the
+ * state in GetCurrentTransactionStopTimestamp().
+ */
+ if (!IsTransactionState())
+ t = GetCurrentTransactionStopTimestamp();
+ else
+ t = GetCurrentTimestamp();
if (t > tabentry->lastscan)
tabentry->lastscan = t;
@@ -1167,3 +1488,45 @@ pgstat_reloid_to_relfilelocator(Oid reloid, RelFileLocator *locator)
ReleaseSysCache(tuple);
return result;
}
+
+/*
+ * Mark that a relation rewrite has occurred, preserving the original locator
+ * so stats can be copied at transaction commit.
+ */
+void
+pgstat_mark_rewrite(RelFileLocator old_locator, RelFileLocator new_locator)
+{
+ PgStat_PendingRewrite *rewrite;
+ PgStat_PendingRewrite *existing;
+ RelFileLocator original_locator = old_locator;
+
+ for (existing = pending_rewrites; existing != NULL; existing = existing->next)
+ {
+ if (old_locator.dbOid == existing->new_locator.dbOid &&
+ old_locator.spcOid == existing->new_locator.spcOid &&
+ old_locator.relNumber == existing->new_locator.relNumber)
+ {
+ original_locator = existing->original_locator;
+ break;
+ }
+ }
+
+ /* Allocate in TopTransactionContext memory context */
+ rewrite = MemoryContextAlloc(TopTransactionContext,
+ sizeof(PgStat_PendingRewrite));
+
+ rewrite->old_locator = old_locator;
+ rewrite->new_locator = new_locator;
+ rewrite->original_locator = original_locator;
+ rewrite->nest_level = GetCurrentTransactionNestLevel();
+
+ /* Add to the list */
+ rewrite->next = pending_rewrites;
+ pending_rewrites = rewrite;
+}
+
+void
+pgstat_clear_rewrite(void)
+{
+ pending_rewrites = NULL;
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index 5e2d69e6297..8ed8f5317f3 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -55,6 +55,8 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
}
pgStatXactStack = NULL;
+ pgstat_clear_rewrite();
+
/* Make sure any stats snapshot is thrown away */
pgstat_clear_snapshot();
}
@@ -360,8 +362,29 @@ create_drop_transactional_internal(PgStat_Kind kind, Oid dboid, uint64 objid, bo
void
pgstat_create_transactional(PgStat_Kind kind, Oid dboid, uint64 objid)
{
- if (pgstat_get_entry_ref(kind, dboid, objid, false, NULL))
+ PgStat_EntryRef *entry_ref;
+
+ entry_ref = pgstat_get_entry_ref(kind, dboid, objid, false, NULL);
+
+ if (entry_ref)
{
+ /*
+ * For relations stats, we key by physical file location, not by
+ * relation OID. This means during operations like ALTER TYPE where
+ * the relation OID changes but the relfilenode stays the same (no
+ * actual rewrite needed), we'll find an existing entry.
+ *
+ * This is expected behavior, we want to preserve stats across the
+ * catalog change. Simply reset and recreate the entry for the new
+ * relation OID without warning.
+ */
+ if (kind == PGSTAT_KIND_RELATION)
+ {
+ pgstat_reset(kind, dboid, objid);
+ create_drop_transactional_internal(kind, dboid, objid, true);
+ return;
+ }
+
ereport(WARNING,
errmsg("resetting existing statistics for kind %s, db=%u, oid=%" PRIu64,
(pgstat_get_kind_info(kind))->name, dboid,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index e19f0d3e51c..bf49830dba2 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -87,6 +87,7 @@
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
+#include "utils/pgstat_internal.h"
#include "utils/relmapper.h"
#include "utils/resowner.h"
#include "utils/snapmgr.h"
@@ -3772,6 +3773,7 @@ RelationSetNewRelfilenumber(Relation relation, char persistence)
MultiXactId minmulti = InvalidMultiXactId;
TransactionId freezeXid = InvalidTransactionId;
RelFileLocator newrlocator;
+ RelFileLocator oldrlocator = relation->rd_locator;
if (!IsBinaryUpgrade)
{
@@ -3943,6 +3945,10 @@ RelationSetNewRelfilenumber(Relation relation, char persistence)
table_close(pg_class, RowExclusiveLock);
+ /* Mark that a rewrite happened */
+ if (RELKIND_HAS_STORAGE(relation->rd_rel->relkind))
+ pgstat_mark_rewrite(oldrlocator, newrlocator);
+
/*
* Make the pg_class row change or relation map change visible. This will
* cause the relcache entry to get updated, too.
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index ef740aff26e..4d3130ae99e 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -701,7 +701,7 @@ extern PgStat_FunctionCounts *find_funcstat_entry(Oid func_id);
extern void pgstat_create_relation(Relation rel);
extern void pgstat_drop_relation(Relation rel);
-extern void pgstat_copy_relation_stats(Relation dst, Relation src);
+extern void pgstat_copy_relation_stats(RelFileLocator dst, RelFileLocator src, bool increment);
extern void pgstat_init_relation(Relation rel);
extern void pgstat_assoc_relation(Relation rel);
@@ -713,6 +713,9 @@ extern void pgstat_report_vacuum(Relation rel, PgStat_Counter livetuples,
extern void pgstat_report_analyze(Relation rel,
PgStat_Counter livetuples, PgStat_Counter deadtuples,
bool resetcounter, TimestampTz starttime);
+extern void pgstat_mark_rewrite(RelFileLocator old_locator,
+ RelFileLocator new_locator);
+extern void pgstat_clear_rewrite(void);
/*
* If stats are enabled, but pending data hasn't been prepared yet, call
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index dbbec84b222..bae04e95989 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2310,6 +2310,7 @@ PgStat_LockEntry
PgStat_PendingDroppedStatsItem
PgStat_PendingIO
PgStat_PendingLock
+PgStat_PendingRewrite
PgStat_SLRUStats
PgStat_ShmemControl
PgStat_Snapshot
--
2.34.1
--96iU9DKeu+W+YlSa--
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