On 22.08.2019 6:13, Kyotaro Horiguchi wrote:
Hello.
At Wed, 21 Aug 2019 18:06:52 +0300, Konstantin Knizhnik <k.knizh...@postgrespro.ru>
wrote in <968fc591-51d3-fd74-8a55-40aa770ba...@postgrespro.ru>
Ok, you convinced me that there are cases when people want to combine
logical replication with streaming replication without slot.
But is it acceptable to have GUC variable (disabled by default) which
allows to use this optimizations?
The odds are quite high. Couldn't we introduce a new wal_level
value instead?
wal_level = logical_only
I think this thread shows that logical replication no longer is a
superset(?) of physical replication. I thougt that we might be
able to change wal_level from scalar to bitmap but it breaks
backward compatibility..
regards.
I can propose the following patch introducing new level logical_only.
I will be please to receive comments concerning adding new wal_level and
possible problems caused by it.
--
Konstantin Knizhnik
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index f1ff01e..1009341 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -719,7 +719,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
* We need to log the copied data in WAL iff WAL archiving/streaming is
* enabled AND it's a WAL-logged rel.
*/
- use_wal = XLogIsNeeded() && RelationNeedsWAL(NewHeap);
+ use_wal = XLogPhysicalIsNeeded() && RelationNeedsWAL(NewHeap);
/* use_wal off requires smgr_targblock be initially invalid */
Assert(RelationGetTargetBlock(NewHeap) == InvalidBlockNumber);
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index a3c4a1d..831d87b 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -466,7 +466,7 @@ vacuum_log_cleanup_info(Relation rel, LVRelStats *vacrelstats)
* Skip this for relations for which no WAL is to be written, or if we're
* not trying to support archive recovery.
*/
- if (!RelationNeedsWAL(rel) || !XLogIsNeeded())
+ if (!RelationNeedsWAL(rel) || !XLogPhysicalIsNeeded())
return;
/*
diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c
index ab19692..4ce1632 100644
--- a/src/backend/access/nbtree/nbtsort.c
+++ b/src/backend/access/nbtree/nbtsort.c
@@ -577,7 +577,7 @@ _bt_leafbuild(BTSpool *btspool, BTSpool *btspool2)
* We need to log index creation in WAL iff WAL archiving/streaming is
* enabled UNLESS the index isn't WAL-logged anyway.
*/
- wstate.btws_use_wal = XLogIsNeeded() && RelationNeedsWAL(wstate.index);
+ wstate.btws_use_wal = XLogPhysicalIsNeeded() && RelationNeedsWAL(wstate.index);
/* reserve the metapage */
wstate.btws_pages_alloced = BTREE_METAPAGE + 1;
diff --git a/src/backend/access/rmgrdesc/xlogdesc.c b/src/backend/access/rmgrdesc/xlogdesc.c
index 33060f3..83c4427 100644
--- a/src/backend/access/rmgrdesc/xlogdesc.c
+++ b/src/backend/access/rmgrdesc/xlogdesc.c
@@ -30,6 +30,7 @@ const struct config_enum_entry wal_level_options[] = {
{"archive", WAL_LEVEL_REPLICA, true}, /* deprecated */
{"hot_standby", WAL_LEVEL_REPLICA, true}, /* deprecated */
{"logical", WAL_LEVEL_LOGICAL, false},
+ {"logical_only", WAL_LEVEL_LOGICAL_ONLY, false},
{NULL, 0, false}
};
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index e651a84..f881ea8 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6155,7 +6155,13 @@ CheckRequiredParameterValues(void)
{
ereport(WARNING,
(errmsg("WAL was generated with wal_level=minimal, data may be missing"),
- errhint("This happens if you temporarily set wal_level=minimal without taking a new base backup.")));
+ errhint("This happens if you temporarily set wal_level=minimal or logical_only without taking a new base backup.")));
+ }
+ if (ArchiveRecoveryRequested && ControlFile->wal_level == WAL_LEVEL_LOGICAL_ONLY)
+ {
+ ereport(WARNING,
+ (errmsg("WAL was generated with wal_level=logical_only, data may be missing"),
+ errhint("This happens if you temporarily set wal_level=logical_only or logical_only without taking a new base backup.")));
}
/*
@@ -6164,7 +6170,7 @@ CheckRequiredParameterValues(void)
*/
if (ArchiveRecoveryRequested && EnableHotStandby)
{
- if (ControlFile->wal_level < WAL_LEVEL_REPLICA)
+ if (ControlFile->wal_level < WAL_LEVEL_REPLICA || ControlFile->wal_level == WAL_LEVEL_LOGICAL_ONLY)
ereport(ERROR,
(errmsg("hot standby is not possible because wal_level was not set to \"replica\" or higher on the master server"),
errhint("Either set wal_level to \"replica\" on the master, or turn off hot_standby here.")));
@@ -10207,7 +10213,7 @@ do_pg_start_backup(const char *backupidstr, bool fast, TimeLineID *starttli_p,
* During recovery, we don't need to check WAL level. Because, if WAL
* level is not sufficient, it's impossible to get here during recovery.
*/
- if (!backup_started_in_recovery && !XLogIsNeeded())
+ if (!backup_started_in_recovery && !XLogPhysicalIsNeeded())
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("WAL level not sufficient for making an online backup"),
@@ -10736,7 +10742,7 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p)
* During recovery, we don't need to check WAL level. Because, if WAL
* level is not sufficient, it's impossible to get here during recovery.
*/
- if (!backup_started_in_recovery && !XLogIsNeeded())
+ if (!backup_started_in_recovery && !XLogPhysicalIsNeeded())
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("WAL level not sufficient for making an online backup"),
diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index 4795c6f..31ab26a 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -316,7 +316,7 @@ pg_create_restore_point(PG_FUNCTION_ARGS)
(errmsg("recovery is in progress"),
errhint("WAL control functions cannot be executed during recovery."))));
- if (!XLogIsNeeded())
+ if (!XLogPhysicalIsNeeded())
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("WAL level not sufficient for creating a restore point"),
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 3cc886f..d8708e9 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -326,7 +326,7 @@ RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
* We need to log the copied data in WAL iff WAL archiving/streaming is
* enabled AND it's a permanent relation.
*/
- use_wal = XLogIsNeeded() &&
+ use_wal = XLogPhysicalIsNeeded() &&
(relpersistence == RELPERSISTENCE_PERMANENT || copying_initfork);
nblocks = smgrnblocks(src, forkNum);
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index f115d4b..7fc0ca9 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -232,7 +232,7 @@ CreatePublication(CreatePublicationStmt *stmt)
InvokeObjectPostCreateHook(PublicationRelationId, puboid, 0);
- if (wal_level != WAL_LEVEL_LOGICAL)
+ if (wal_level < WAL_LEVEL_LOGICAL)
{
ereport(WARNING,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index cceefbd..32f75e3 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -4772,7 +4772,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
bistate = GetBulkInsertState();
ti_options = TABLE_INSERT_SKIP_FSM;
- if (!XLogIsNeeded())
+ if (!XLogPhysicalIsNeeded())
ti_options |= TABLE_INSERT_SKIP_WAL;
}
else
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 3339804..ca01fd7 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -896,6 +896,9 @@ PostmasterMain(int argc, char *argv[])
if (XLogArchiveMode > ARCHIVE_MODE_OFF && wal_level == WAL_LEVEL_MINIMAL)
ereport(ERROR,
(errmsg("WAL archival cannot be enabled when wal_level is \"minimal\"")));
+ if (XLogArchiveMode > ARCHIVE_MODE_OFF && wal_level == WAL_LEVEL_LOGICAL_ONLY)
+ ereport(ERROR,
+ (errmsg("WAL archival cannot be enabled when wal_level is \"logical_only\"")));
if (max_wal_senders > 0 && wal_level == WAL_LEVEL_MINIMAL)
ereport(ERROR,
(errmsg("WAL streaming (max_wal_senders > 0) requires wal_level \"replica\" or \"logical\"")));
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index b1bcd93..7ea26bb 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -1523,6 +1523,12 @@ RestoreSlotFromDisk(const char *name)
errmsg("logical replication slot \"%s\" exists, but wal_level < logical",
NameStr(cp.slotdata.name)),
errhint("Change wal_level to be logical or higher.")));
+ else if (wal_level == WAL_LEVEL_LOGICAL_ONLY)
+ ereport(FATAL,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("physical replication slot \"%s\" exists, but wal_level = logical_only",
+ NameStr(cp.slotdata.name)),
+ errhint("Change wal_level to be replica or logical.")));
else if (wal_level < WAL_LEVEL_REPLICA)
ereport(FATAL,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 23870a2..9dd5e2f 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -542,6 +542,11 @@ StartReplication(StartReplicationCmd *cmd)
StringInfoData buf;
XLogRecPtr FlushPtr;
+ if (wal_level == WAL_LEVEL_LOGICAL_ONLY)
+ ereport(ERROR,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ (errmsg("cannot start physical replication in logical_only WAl mode"))));
+
if (ThisTimeLineID == 0)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
diff --git a/src/bin/pg_controldata/pg_controldata.c b/src/bin/pg_controldata/pg_controldata.c
index ff17804..d584dcf 100644
--- a/src/bin/pg_controldata/pg_controldata.c
+++ b/src/bin/pg_controldata/pg_controldata.c
@@ -80,6 +80,8 @@ wal_level_str(WalLevel wal_level)
return "replica";
case WAL_LEVEL_LOGICAL:
return "logical";
+ case WAL_LEVEL_LOGICAL_ONLY:
+ return "logical_only";
}
return _("unrecognized wal_level");
}
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index d519252..a44c5b3 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -161,17 +161,18 @@ typedef enum WalLevel
{
WAL_LEVEL_MINIMAL = 0,
WAL_LEVEL_REPLICA,
- WAL_LEVEL_LOGICAL
+ WAL_LEVEL_LOGICAL,
+ WAL_LEVEL_LOGICAL_ONLY
} WalLevel;
extern PGDLLIMPORT int wal_level;
/* Is WAL archiving enabled (always or only while server is running normally)? */
#define XLogArchivingActive() \
- (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode > ARCHIVE_MODE_OFF)
+ (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || XLogPhysicalIsNeeded()), XLogArchiveMode > ARCHIVE_MODE_OFF)
/* Is WAL archiving enabled always (even during recovery)? */
#define XLogArchivingAlways() \
- (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode == ARCHIVE_MODE_ALWAYS)
+ (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || XLogPhysicalIsNeeded()), XLogArchiveMode == ARCHIVE_MODE_ALWAYS)
#define XLogArchiveCommandSet() (XLogArchiveCommand[0] != '\0')
/*
@@ -181,6 +182,11 @@ extern PGDLLIMPORT int wal_level;
#define XLogIsNeeded() (wal_level >= WAL_LEVEL_REPLICA)
/*
+ * Is WAL-logging necessary for archival or physical replication?
+ */
+#define XLogPhysicalIsNeeded() (XLogIsNeeded() && wal_level != WAL_LEVEL_LOGICAL_ONLY)
+
+/*
* Is a full-page image needed for hint bit updates?
*
* Normally, we don't WAL-log hint bit updates, but if checksums are enabled,
