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-rw-r--r--src/backend/access/heap/heapam.c10
-rw-r--r--src/backend/access/transam/xact.c2
-rw-r--r--src/backend/access/transam/xlog.c118
-rw-r--r--src/backend/access/transam/xlogfuncs.c2
-rw-r--r--src/backend/access/transam/xloginsert.c24
5 files changed, 114 insertions, 42 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index b019bc1a0d9..ea579a00bec 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2507,7 +2507,7 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
heaptup->t_len - SizeofHeapTupleHeader);
/* filtering by origin on a row level is much more efficient */
- XLogIncludeOrigin();
+ XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
recptr = XLogInsert(RM_HEAP_ID, info);
@@ -2846,7 +2846,7 @@ heap_multi_insert(Relation relation, HeapTuple *tuples, int ntuples,
XLogRegisterBufData(0, tupledata, totaldatalen);
/* filtering by origin on a row level is much more efficient */
- XLogIncludeOrigin();
+ XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
recptr = XLogInsert(RM_HEAP2_ID, info);
@@ -3308,7 +3308,7 @@ l1:
}
/* filtering by origin on a row level is much more efficient */
- XLogIncludeOrigin();
+ XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_DELETE);
@@ -6035,7 +6035,7 @@ heap_finish_speculative(Relation relation, HeapTuple tuple)
XLogBeginInsert();
/* We want the same filtering on this as on a plain insert */
- XLogIncludeOrigin();
+ XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
XLogRegisterData((char *) &xlrec, SizeOfHeapConfirm);
XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
@@ -7703,7 +7703,7 @@ log_heap_update(Relation reln, Buffer oldbuf,
}
/* filtering by origin on a row level is much more efficient */
- XLogIncludeOrigin();
+ XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
recptr = XLogInsert(RM_HEAP_ID, info);
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index d6432165f1e..e47fd4497e3 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -5234,7 +5234,7 @@ XactLogCommitRecord(TimestampTz commit_time,
XLogRegisterData((char *) (&xl_origin), sizeof(xl_xact_origin));
/* we allow filtering by xacts */
- XLogIncludeOrigin();
+ XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
return XLogInsert(RM_XACT_ID, info);
}
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index aa9ee5a0dd8..f8ffa5c45cb 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -442,11 +442,21 @@ typedef struct XLogwrtResult
* the WAL record is just copied to the page and the lock is released. But
* to avoid the deadlock-scenario explained above, the indicator is always
* updated before sleeping while holding an insertion lock.
+ *
+ * lastImportantAt contains the LSN of the last important WAL record inserted
+ * using a given lock. This value is used to detect if there has been
+ * important WAL activity since the last time some action, like a checkpoint,
+ * was performed - allowing to not repeat the action if not. The LSN is
+ * updated for all insertions, unless the XLOG_MARK_UNIMPORTANT flag was
+ * set. lastImportantAt is never cleared, only overwritten by the LSN of newer
+ * records. Tracking the WAL activity directly in WALInsertLock has the
+ * advantage of not needing any additional locks to update the value.
*/
typedef struct
{
LWLock lock;
XLogRecPtr insertingAt;
+ XLogRecPtr lastImportantAt;
} WALInsertLock;
/*
@@ -541,8 +551,9 @@ typedef struct XLogCtlData
XLogRecPtr unloggedLSN;
slock_t ulsn_lck;
- /* Time of last xlog segment switch. Protected by WALWriteLock. */
+ /* Time and LSN of last xlog segment switch. Protected by WALWriteLock. */
pg_time_t lastSegSwitchTime;
+ XLogRecPtr lastSegSwitchLSN;
/*
* Protected by info_lck and WALWriteLock (you must hold either lock to
@@ -884,6 +895,9 @@ static void WALInsertLockUpdateInsertingAt(XLogRecPtr insertingAt);
* which pages need a full-page image, and retry. If fpw_lsn is invalid, the
* record is always inserted.
*
+ * 'flags' gives more in-depth control on the record being inserted. See
+ * XLogSetRecordFlags() for details.
+ *
* The first XLogRecData in the chain must be for the record header, and its
* data must be MAXALIGNed. XLogInsertRecord fills in the xl_prev and
* xl_crc fields in the header, the rest of the header must already be filled
@@ -896,7 +910,9 @@ static void WALInsertLockUpdateInsertingAt(XLogRecPtr insertingAt);
* WAL rule "write the log before the data".)
*/
XLogRecPtr
-XLogInsertRecord(XLogRecData *rdata, XLogRecPtr fpw_lsn)
+XLogInsertRecord(XLogRecData *rdata,
+ XLogRecPtr fpw_lsn,
+ uint8 flags)
{
XLogCtlInsert *Insert = &XLogCtl->Insert;
pg_crc32c rdata_crc;
@@ -1013,6 +1029,18 @@ XLogInsertRecord(XLogRecData *rdata, XLogRecPtr fpw_lsn)
*/
CopyXLogRecordToWAL(rechdr->xl_tot_len, isLogSwitch, rdata,
StartPos, EndPos);
+
+ /*
+ * Unless record is flagged as not important, update LSN of last
+ * important record in the current slot. When holding all locks, just
+ * update the first one.
+ */
+ if ((flags & XLOG_MARK_UNIMPORTANT) == 0)
+ {
+ int lockno = holdingAllLocks ? 0 : MyLockNo;
+
+ WALInsertLocks[lockno].l.lastImportantAt = StartPos;
+ }
}
else
{
@@ -2332,6 +2360,7 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
XLogArchiveNotifySeg(openLogSegNo);
XLogCtl->lastSegSwitchTime = (pg_time_t) time(NULL);
+ XLogCtl->lastSegSwitchLSN = LogwrtResult.Flush;
/*
* Request a checkpoint if we've consumed too much xlog since
@@ -4715,6 +4744,7 @@ XLOGShmemInit(void)
{
LWLockInitialize(&WALInsertLocks[i].l.lock, LWTRANCHE_WAL_INSERT);
WALInsertLocks[i].l.insertingAt = InvalidXLogRecPtr;
+ WALInsertLocks[i].l.lastImportantAt = InvalidXLogRecPtr;
}
/*
@@ -7431,8 +7461,9 @@ StartupXLOG(void)
*/
InRecovery = false;
- /* start the archive_timeout timer running */
+ /* start the archive_timeout timer and LSN running */
XLogCtl->lastSegSwitchTime = (pg_time_t) time(NULL);
+ XLogCtl->lastSegSwitchLSN = EndOfLog;
/* also initialize latestCompletedXid, to nextXid - 1 */
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
@@ -7994,16 +8025,51 @@ GetFlushRecPtr(void)
}
/*
- * Get the time of the last xlog segment switch
+ * GetLastImportantRecPtr -- Returns the LSN of the last important record
+ * inserted. All records not explicitly marked as unimportant are considered
+ * important.
+ *
+ * The LSN is determined by computing the maximum of
+ * WALInsertLocks[i].lastImportantAt.
+ */
+XLogRecPtr
+GetLastImportantRecPtr(void)
+{
+ XLogRecPtr res = InvalidXLogRecPtr;
+ int i;
+
+ for (i = 0; i < NUM_XLOGINSERT_LOCKS; i++)
+ {
+ XLogRecPtr last_important;
+
+ /*
+ * Need to take a lock to prevent torn reads of the LSN, which are
+ * possible on some of the supported platforms. WAL insert locks only
+ * support exclusive mode, so we have to use that.
+ */
+ LWLockAcquire(&WALInsertLocks[i].l.lock, LW_EXCLUSIVE);
+ last_important = WALInsertLocks[i].l.lastImportantAt;
+ LWLockRelease(&WALInsertLocks[i].l.lock);
+
+ if (res < last_important)
+ res = last_important;
+ }
+
+ return res;
+}
+
+/*
+ * Get the time and LSN of the last xlog segment switch
*/
pg_time_t
-GetLastSegSwitchTime(void)
+GetLastSegSwitchData(XLogRecPtr *lastSwitchLSN)
{
pg_time_t result;
/* Need WALWriteLock, but shared lock is sufficient */
LWLockAcquire(WALWriteLock, LW_SHARED);
result = XLogCtl->lastSegSwitchTime;
+ *lastSwitchLSN = XLogCtl->lastSegSwitchLSN;
LWLockRelease(WALWriteLock);
return result;
@@ -8065,7 +8131,7 @@ ShutdownXLOG(int code, Datum arg)
* record will go to the next XLOG file and won't be archived (yet).
*/
if (XLogArchivingActive() && XLogArchiveCommandSet())
- RequestXLogSwitch();
+ RequestXLogSwitch(false);
CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE);
}
@@ -8253,7 +8319,7 @@ CreateCheckPoint(int flags)
uint32 freespace;
XLogRecPtr PriorRedoPtr;
XLogRecPtr curInsert;
- XLogRecPtr prevPtr;
+ XLogRecPtr last_important_lsn;
VirtualTransactionId *vxids;
int nvxids;
@@ -8334,38 +8400,33 @@ CreateCheckPoint(int flags)
checkPoint.oldestActiveXid = InvalidTransactionId;
/*
+ * Get location of last important record before acquiring insert locks (as
+ * GetLastImportantRecPtr() also locks WAL locks).
+ */
+ last_important_lsn = GetLastImportantRecPtr();
+
+ /*
* We must block concurrent insertions while examining insert state to
* determine the checkpoint REDO pointer.
*/
WALInsertLockAcquireExclusive();
curInsert = XLogBytePosToRecPtr(Insert->CurrBytePos);
- prevPtr = XLogBytePosToRecPtr(Insert->PrevBytePos);
/*
- * If this isn't a shutdown or forced checkpoint, and we have not inserted
- * any XLOG records since the start of the last checkpoint, skip the
- * checkpoint. The idea here is to avoid inserting duplicate checkpoints
- * when the system is idle. That wastes log space, and more importantly it
- * exposes us to possible loss of both current and previous checkpoint
- * records if the machine crashes just as we're writing the update.
- * (Perhaps it'd make even more sense to checkpoint only when the previous
- * checkpoint record is in a different xlog page?)
- *
- * If the previous checkpoint crossed a WAL segment, however, we create
- * the checkpoint anyway, to have the latest checkpoint fully contained in
- * the new segment. This is for a little bit of extra robustness: it's
- * better if you don't need to keep two WAL segments around to recover the
- * checkpoint.
+ * If this isn't a shutdown or forced checkpoint, and if there has been no
+ * WAL activity requiring a checkpoint, skip it. The idea here is to
+ * avoid inserting duplicate checkpoints when the system is idle.
*/
if ((flags & (CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_END_OF_RECOVERY |
CHECKPOINT_FORCE)) == 0)
{
- if (prevPtr == ControlFile->checkPointCopy.redo &&
- prevPtr / XLOG_SEG_SIZE == curInsert / XLOG_SEG_SIZE)
+ if (last_important_lsn == ControlFile->checkPoint)
{
WALInsertLockRelease();
LWLockRelease(CheckpointLock);
END_CRIT_SECTION();
+ ereport(DEBUG1,
+ (errmsg("checkpoint skipped due to an idle system")));
return;
}
}
@@ -9122,12 +9183,15 @@ XLogPutNextOid(Oid nextOid)
* write a switch record because we are already at segment start.
*/
XLogRecPtr
-RequestXLogSwitch(void)
+RequestXLogSwitch(bool mark_unimportant)
{
XLogRecPtr RecPtr;
/* XLOG SWITCH has no data */
XLogBeginInsert();
+
+ if (mark_unimportant)
+ XLogSetRecordFlags(XLOG_MARK_UNIMPORTANT);
RecPtr = XLogInsert(RM_XLOG_ID, XLOG_SWITCH);
return RecPtr;
@@ -9997,7 +10061,7 @@ do_pg_start_backup(const char *backupidstr, bool fast, TimeLineID *starttli_p,
* recovery case described above.
*/
if (!backup_started_in_recovery)
- RequestXLogSwitch();
+ RequestXLogSwitch(false);
do
{
@@ -10582,7 +10646,7 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p)
* Force a switch to a new xlog segment file, so that the backup is valid
* as soon as archiver moves out the current segment file.
*/
- RequestXLogSwitch();
+ RequestXLogSwitch(false);
XLByteToPrevSeg(stoppoint, _logSegNo);
XLogFileName(stopxlogfilename, ThisTimeLineID, _logSegNo);
diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index 01cbd90f40a..bc7253fc9bc 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -293,7 +293,7 @@ pg_switch_xlog(PG_FUNCTION_ARGS)
errmsg("recovery is in progress"),
errhint("WAL control functions cannot be executed during recovery.")));
- switchpoint = RequestXLogSwitch();
+ switchpoint = RequestXLogSwitch(false);
/*
* As a convenience, return the WAL location of the switch record
diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c
index 3cd273b19f2..24e35a38453 100644
--- a/src/backend/access/transam/xloginsert.c
+++ b/src/backend/access/transam/xloginsert.c
@@ -73,8 +73,8 @@ static XLogRecData *mainrdata_head;
static XLogRecData *mainrdata_last = (XLogRecData *) &mainrdata_head;
static uint32 mainrdata_len; /* total # of bytes in chain */
-/* Should the in-progress insertion log the origin? */
-static bool include_origin = false;
+/* flags for the in-progress insertion */
+static uint8 curinsert_flags = 0;
/*
* These are used to hold the record header while constructing a record.
@@ -201,7 +201,7 @@ XLogResetInsertion(void)
max_registered_block_id = 0;
mainrdata_len = 0;
mainrdata_last = (XLogRecData *) &mainrdata_head;
- include_origin = false;
+ curinsert_flags = 0;
begininsert_called = false;
}
@@ -384,13 +384,20 @@ XLogRegisterBufData(uint8 block_id, char *data, int len)
}
/*
- * Should this record include the replication origin if one is set up?
+ * Set insert status flags for the upcoming WAL record.
+ *
+ * The flags that can be used here are:
+ * - XLOG_INCLUDE_ORIGIN, to determine if the replication origin should be
+ * included in the record.
+ * - XLOG_MARK_UNIMPORTANT, to signal that the record is not important for
+ * durability, which allows to avoid triggering WAL archiving and other
+ * background activity.
*/
void
-XLogIncludeOrigin(void)
+XLogSetRecordFlags(uint8 flags)
{
Assert(begininsert_called);
- include_origin = true;
+ curinsert_flags = flags;
}
/*
@@ -450,7 +457,7 @@ XLogInsert(RmgrId rmid, uint8 info)
rdt = XLogRecordAssemble(rmid, info, RedoRecPtr, doPageWrites,
&fpw_lsn);
- EndPos = XLogInsertRecord(rdt, fpw_lsn);
+ EndPos = XLogInsertRecord(rdt, fpw_lsn, curinsert_flags);
} while (EndPos == InvalidXLogRecPtr);
XLogResetInsertion();
@@ -701,7 +708,8 @@ XLogRecordAssemble(RmgrId rmid, uint8 info,
}
/* followed by the record's origin, if any */
- if (include_origin && replorigin_session_origin != InvalidRepOriginId)
+ if ((curinsert_flags & XLOG_INCLUDE_ORIGIN) &&
+ replorigin_session_origin != InvalidRepOriginId)
{
*(scratch++) = XLR_BLOCK_ID_ORIGIN;
memcpy(scratch, &replorigin_session_origin, sizeof(replorigin_session_origin));
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-16 10:18:19 +0000