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* [PATCH v52 02/10] Rename cluster.c/h -> repack.c/h
@ 2026-03-31 16:55 Álvaro Herrera <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Álvaro Herrera @ 2026-03-31 16:55 UTC (permalink / raw)
---
src/backend/commands/Makefile | 2 +-
src/backend/commands/matview.c | 2 +-
src/backend/commands/meson.build | 2 +-
src/backend/commands/{cluster.c => repack.c} | 6 +++---
src/backend/commands/tablecmds.c | 2 +-
src/backend/commands/vacuum.c | 6 +++---
src/backend/storage/ipc/procsignal.c | 1 +
src/backend/tcop/postgres.c | 1 +
src/backend/tcop/utility.c | 2 +-
src/include/commands/{cluster.h => repack.h} | 12 ++++++------
10 files changed, 19 insertions(+), 17 deletions(-)
rename src/backend/commands/{cluster.c => repack.c} (99%)
rename src/include/commands/{cluster.h => repack.h} (90%)
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index c10fdba2bbb..fe1bba3a9b9 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -18,7 +18,6 @@ OBJS = \
amcmds.o \
analyze.o \
async.o \
- cluster.o \
collationcmds.o \
comment.o \
constraint.o \
@@ -51,6 +50,7 @@ OBJS = \
proclang.o \
propgraphcmds.o \
publicationcmds.o \
+ repack.o \
schemacmds.o \
seclabel.o \
sequence.o \
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index d3be8939011..5db4fe75dce 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -24,8 +24,8 @@
#include "catalog/namespace.h"
#include "catalog/pg_am.h"
#include "catalog/pg_opclass.h"
-#include "commands/cluster.h"
#include "commands/matview.h"
+#include "commands/repack.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
#include "executor/executor.h"
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index 90c7e37a429..f624aae74af 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -6,7 +6,6 @@ backend_sources += files(
'amcmds.c',
'analyze.c',
'async.c',
- 'cluster.c',
'collationcmds.c',
'comment.c',
'constraint.c',
@@ -39,6 +38,7 @@ backend_sources += files(
'proclang.c',
'propgraphcmds.c',
'publicationcmds.c',
+ 'repack.c',
'schemacmds.c',
'seclabel.c',
'sequence.c',
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/repack.c
similarity index 99%
rename from src/backend/commands/cluster.c
rename to src/backend/commands/repack.c
index f241e18b153..20f0a572236 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/repack.c
@@ -1,6 +1,6 @@
/*-------------------------------------------------------------------------
*
- * cluster.c
+ * repack.c
* REPACK a table; formerly known as CLUSTER. VACUUM FULL also uses
* parts of this code.
*
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * src/backend/commands/cluster.c
+ * src/backend/commands/repack.c
*
*-------------------------------------------------------------------------
*/
@@ -33,9 +33,9 @@
#include "catalog/pg_am.h"
#include "catalog/pg_inherits.h"
#include "catalog/toasting.h"
-#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/progress.h"
+#include "commands/repack.h"
#include "commands/tablecmds.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 0ce2e81f9c2..e2882a50b3b 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -57,10 +57,10 @@
#include "catalog/storage.h"
#include "catalog/storage_xlog.h"
#include "catalog/toasting.h"
-#include "commands/cluster.h"
#include "commands/comment.h"
#include "commands/defrem.h"
#include "commands/event_trigger.h"
+#include "commands/repack.h"
#include "commands/sequence.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 0ed363d1c85..b179b62b5c8 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -9,7 +9,7 @@
*
* VACUUM for heap AM is implemented in vacuumlazy.c, parallel vacuum in
* vacuumparallel.c, ANALYZE in analyze.c, and VACUUM FULL is a variant of
- * CLUSTER, handled in cluster.c.
+ * REPACK, handled in repack.c.
*
*
* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
@@ -38,9 +38,9 @@
#include "catalog/pg_database.h"
#include "catalog/pg_inherits.h"
#include "commands/async.h"
-#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/progress.h"
+#include "commands/repack.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
@@ -2293,7 +2293,7 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
if ((params.options & VACOPT_VERBOSE) != 0)
cluster_params.options |= CLUOPT_VERBOSE;
- /* VACUUM FULL is a variant of REPACK; see cluster.c */
+ /* VACUUM FULL is a variant of REPACK; see repack.c */
cluster_rel(REPACK_COMMAND_VACUUMFULL, rel, InvalidOid,
&cluster_params);
/* cluster_rel closes the relation, but keeps lock */
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 7e017c8d53b..7cef6e43661 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -19,6 +19,7 @@
#include "access/parallel.h"
#include "commands/async.h"
+#include "commands/repack.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "port/pg_bitutils.h"
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 10be60011ad..9fbaa5c00f0 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -39,6 +39,7 @@
#include "commands/event_trigger.h"
#include "commands/explain_state.h"
#include "commands/prepare.h"
+#include "commands/repack.h"
#include "common/pg_prng.h"
#include "jit/jit.h"
#include "libpq/libpq.h"
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 2b609bfc824..5f8c766c4be 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -26,7 +26,6 @@
#include "catalog/toasting.h"
#include "commands/alter.h"
#include "commands/async.h"
-#include "commands/cluster.h"
#include "commands/collationcmds.h"
#include "commands/comment.h"
#include "commands/conversioncmds.h"
@@ -46,6 +45,7 @@
#include "commands/proclang.h"
#include "commands/propgraphcmds.h"
#include "commands/publicationcmds.h"
+#include "commands/repack.h"
#include "commands/schemacmds.h"
#include "commands/seclabel.h"
#include "commands/sequence.h"
diff --git a/src/include/commands/cluster.h b/src/include/commands/repack.h
similarity index 90%
rename from src/include/commands/cluster.h
rename to src/include/commands/repack.h
index d6b62c747e8..85061158b0c 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/repack.h
@@ -1,17 +1,17 @@
/*-------------------------------------------------------------------------
*
- * cluster.h
- * header file for postgres cluster command stuff
+ * repack.h
+ * header file for the REPACK command
*
* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
- * src/include/commands/cluster.h
+ * src/include/commands/repack.h
*
*-------------------------------------------------------------------------
*/
-#ifndef CLUSTER_H
-#define CLUSTER_H
+#ifndef REPACK_H
+#define REPACK_H
#include "nodes/parsenodes.h"
#include "parser/parse_node.h"
@@ -52,4 +52,4 @@ extern void finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
MultiXactId cutoffMulti,
char newrelpersistence);
-#endif /* CLUSTER_H */
+#endif /* REPACK_H */
--
2.47.3
--gp2pyozrd5pweboh
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
filename="v52-0003-Add-CONCURRENTLY-option-to-REPACK-command.patch"
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-06-16 11:54 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 6f3e4ecff46..92c1b678e6f 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -186,6 +186,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2014,13 +2016,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2029,9 +2024,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2063,6 +2056,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2178,15 +2174,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2288,9 +2275,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2391,9 +2377,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2403,6 +2388,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2420,6 +2435,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2436,7 +2452,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2492,37 +2508,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4072,9 +4071,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v01-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
* [PATCH 7/8] Decouple updating of freezing information from swap_relation_files().
@ 2026-07-15 08:37 Antonin Houska <[email protected]>
0 siblings, 0 replies; 234+ messages in thread
From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)
So far, the relfrozenxid and relminmxid attributes of pg_class used to be
updated by swap_relation_files(), however, not every call of the function
should do that. On the contrary, new feature of REPACK (CONCURRENTLY) will
need to update this information in one case that would be tricky to handle
using swap_relation_files().
---
src/backend/commands/repack.c | 114 +++++++++++++++++-----------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 89695335127..7390fd303f6 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -188,6 +188,8 @@ static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldInde
TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti,
ChangeContext *chgcxt);
+static void update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti);
static List *get_tables_to_repack(RepackCommand cmd, bool usingindex,
MemoryContext permcxt);
static List *get_tables_to_repack_partitioned(RepackCommand cmd,
@@ -2039,13 +2041,6 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex,
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
- * Additionally, the first relation is marked with relfrozenxid set to
- * frozenXid. It seems a bit ugly to have this here, but the caller would
- * have to do it anyway, so having it here saves a heap_update. Note: in
- * the swap-toast-links case, we assume we don't need to change the toast
- * table's relfrozenxid: the new version of the toast table should already
- * have relfrozenxid set to RecentXmin, which is good enough.
- *
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
@@ -2054,9 +2049,7 @@ static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
- TransactionId frozenXid,
- MultiXactId cutoffMulti,
- Oid *mapped_tables)
+ Oid *mapped_tables, Oid *r1_toastid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -2088,6 +2081,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relam1 = relform1->relam;
relam2 = relform2->relam;
+ if (r1_toastid)
+ *r1_toastid = relform1->reltoastrelid;
+
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
@@ -2203,15 +2199,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
* and then fail to commit the pg_class update.
*/
- /* set rel1's frozen Xid and minimum MultiXid */
- if (relform1->relkind != RELKIND_INDEX)
- {
- Assert(!TransactionIdIsValid(frozenXid) ||
- TransactionIdIsNormal(frozenXid));
- relform1->relfrozenxid = frozenXid;
- relform1->relminmxid = cutoffMulti;
- }
-
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
@@ -2313,9 +2300,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- frozenXid,
- cutoffMulti,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
else
{
@@ -2416,9 +2402,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
target_is_pg_class,
swap_toast_by_content,
is_internal,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
}
/* Clean up. */
@@ -2428,6 +2413,36 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
table_close(relRelation, RowExclusiveLock);
}
+/*
+ * Update relfrozenxid and relminmxid attributes of pg_class entry, specified
+ * by OID.
+ */
+static void
+update_relation_cutoffs(Oid relid, TransactionId frozenXid,
+ MultiXactId cutoffMulti)
+{
+ Relation relRelation;
+ HeapTuple reltup;
+ Form_pg_class relform;
+ CatalogIndexState indstate;
+
+ relRelation = table_open(RelationRelationId, RowExclusiveLock);
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u", relid);
+ relform = (Form_pg_class) GETSTRUCT(reltup);
+ relform->relfrozenxid = frozenXid;
+ relform->relminmxid = cutoffMulti;
+
+ indstate = CatalogOpenIndexes(relRelation);
+ CatalogTupleUpdateWithInfo(relRelation, &reltup->t_self, reltup,
+ indstate);
+ CatalogCloseIndexes(indstate);
+
+ heap_freetuple(reltup);
+ table_close(relRelation, RowExclusiveLock);
+}
+
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
@@ -2445,6 +2460,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
{
ObjectAddress object;
Oid mapped_tables[4];
+ Oid oid_old_toastid;
int i;
/* Report that we are now swapping relation files */
@@ -2461,7 +2477,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
- frozenXid, cutoffMulti, mapped_tables);
+ mapped_tables, &oid_old_toastid);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
@@ -2517,37 +2533,20 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
PROGRESS_REPACK_PHASE_FINAL_CLEANUP);
/*
- * If the relation being rebuilt is pg_class, swap_relation_files()
- * couldn't update pg_class's own pg_class entry (check comments in
- * swap_relation_files()), thus relfrozenxid was not updated. That's
- * annoying because a potential reason for doing a VACUUM FULL is a
- * imminent or actual anti-wraparound shutdown. So, now that we can
- * access the new relation using its indices, update relfrozenxid.
- * pg_class doesn't have a toast relation, so we don't need to update the
- * corresponding toast relation. Not that there's little point moving all
- * relfrozenxid updates here since swap_relation_files() needs to write to
- * pg_class for non-mapped relations anyway.
+ * Update relfrozenxid and relminmxid. CCI is needed to see the most
+ * recent pg_class tuple, created by swap_relation_files(). However that
+ * CCI makes us use the new relation file. Therefore we cannot do this
+ * before indexes have been rebuilt too.
*/
- if (OIDOldHeap == RelationRelationId)
- {
- Relation relRelation;
- HeapTuple reltup;
- Form_pg_class relform;
-
- relRelation = table_open(RelationRelationId, RowExclusiveLock);
-
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
- relform = (Form_pg_class) GETSTRUCT(reltup);
-
- relform->relfrozenxid = frozenXid;
- relform->relminmxid = cutoffMulti;
-
- CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
+ CommandCounterIncrement();
+ update_relation_cutoffs(OIDOldHeap, frozenXid, cutoffMulti);
- table_close(relRelation, RowExclusiveLock);
- }
+ /*
+ * The same for TOAST, if needed. In the swap-toast-links case, the new
+ * the toast table should already have relfrozenxid set to RecentXmin.
+ */
+ if (OidIsValid(oid_old_toastid) && swap_toast_by_content)
+ update_relation_cutoffs(oid_old_toastid, frozenXid, cutoffMulti);
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
@@ -4133,9 +4132,8 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
(old_table_oid == RelationRelationId),
false, /* swap_toast_by_content */
true,
- InvalidTransactionId,
- InvalidMultiXactId,
- mapped_tables);
+ mapped_tables,
+ NULL);
#ifdef USE_ASSERT_CHECKING
--
2.52.0
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
filename=v02-0008-Make-REPACK-CONCURRENTLY-MVCC-safe.patch
^ permalink raw reply [nested|flat] 234+ messages in thread
end of thread, other threads:[~2026-07-15 08:37 UTC | newest]
Thread overview: 234+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2026-03-31 16:55 [PATCH v52 02/10] Rename cluster.c/h -> repack.c/h Álvaro Herrera <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-06-16 11:54 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
2026-07-15 08:37 [PATCH 7/8] Decouple updating of freezing information from swap_relation_files(). Antonin Houska <[email protected]>
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