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-rw-r--r--src/backend/access/rmgrdesc/xlogdesc.c47
-rw-r--r--src/backend/access/transam/xlog.c8
-rw-r--r--src/backend/postmaster/walsummarizer.c197
3 files changed, 178 insertions, 74 deletions
diff --git a/src/backend/access/rmgrdesc/xlogdesc.c b/src/backend/access/rmgrdesc/xlogdesc.c
index e455400716d..363294d6234 100644
--- a/src/backend/access/rmgrdesc/xlogdesc.c
+++ b/src/backend/access/rmgrdesc/xlogdesc.c
@@ -33,6 +33,27 @@ const struct config_enum_entry wal_level_options[] = {
{NULL, 0, false}
};
+/*
+ * Find a string representation for wal_level
+ */
+static const char *
+get_wal_level_string(int wal_level)
+{
+ const struct config_enum_entry *entry;
+ const char *wal_level_str = "?";
+
+ for (entry = wal_level_options; entry->name; entry++)
+ {
+ if (entry->val == wal_level)
+ {
+ wal_level_str = entry->name;
+ break;
+ }
+ }
+
+ return wal_level_str;
+}
+
void
xlog_desc(StringInfo buf, XLogReaderState *record)
{
@@ -45,7 +66,7 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
CheckPoint *checkpoint = (CheckPoint *) rec;
appendStringInfo(buf, "redo %X/%X; "
- "tli %u; prev tli %u; fpw %s; xid %u:%u; oid %u; multi %u; offset %u; "
+ "tli %u; prev tli %u; fpw %s; wal_level %s; xid %u:%u; oid %u; multi %u; offset %u; "
"oldest xid %u in DB %u; oldest multi %u in DB %u; "
"oldest/newest commit timestamp xid: %u/%u; "
"oldest running xid %u; %s",
@@ -53,6 +74,7 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
checkpoint->ThisTimeLineID,
checkpoint->PrevTimeLineID,
checkpoint->fullPageWrites ? "true" : "false",
+ get_wal_level_string(checkpoint->wal_level),
EpochFromFullTransactionId(checkpoint->nextXid),
XidFromFullTransactionId(checkpoint->nextXid),
checkpoint->nextOid,
@@ -95,20 +117,9 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
{
xl_parameter_change xlrec;
const char *wal_level_str;
- const struct config_enum_entry *entry;
memcpy(&xlrec, rec, sizeof(xl_parameter_change));
-
- /* Find a string representation for wal_level */
- wal_level_str = "?";
- for (entry = wal_level_options; entry->name; entry++)
- {
- if (entry->val == xlrec.wal_level)
- {
- wal_level_str = entry->name;
- break;
- }
- }
+ wal_level_str = get_wal_level_string(xlrec.wal_level);
appendStringInfo(buf, "max_connections=%d max_worker_processes=%d "
"max_wal_senders=%d max_prepared_xacts=%d "
@@ -135,9 +146,10 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
xl_end_of_recovery xlrec;
memcpy(&xlrec, rec, sizeof(xl_end_of_recovery));
- appendStringInfo(buf, "tli %u; prev tli %u; time %s",
+ appendStringInfo(buf, "tli %u; prev tli %u; time %s; wal_level %s",
xlrec.ThisTimeLineID, xlrec.PrevTimeLineID,
- timestamptz_to_str(xlrec.end_time));
+ timestamptz_to_str(xlrec.end_time),
+ get_wal_level_string(xlrec.wal_level));
}
else if (info == XLOG_OVERWRITE_CONTRECORD)
{
@@ -150,7 +162,10 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
}
else if (info == XLOG_CHECKPOINT_REDO)
{
- /* No details to write out */
+ int wal_level;
+
+ memcpy(&wal_level, rec, sizeof(int));
+ appendStringInfo(buf, "wal_level %s", get_wal_level_string(wal_level));
}
}
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index d36272ab4ff..a864959296f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6934,6 +6934,7 @@ CreateCheckPoint(int flags)
WALInsertLockAcquireExclusive();
checkPoint.fullPageWrites = Insert->fullPageWrites;
+ checkPoint.wal_level = wal_level;
if (shutdown)
{
@@ -6987,11 +6988,9 @@ CreateCheckPoint(int flags)
*/
if (!shutdown)
{
- int dummy = 0;
-
- /* Record must have payload to avoid assertion failure. */
+ /* Include WAL level in record for WAL summarizer's benefit. */
XLogBeginInsert();
- XLogRegisterData((char *) &dummy, sizeof(dummy));
+ XLogRegisterData((char *) &wal_level, sizeof(wal_level));
(void) XLogInsert(RM_XLOG_ID, XLOG_CHECKPOINT_REDO);
/*
@@ -7314,6 +7313,7 @@ CreateEndOfRecoveryRecord(void)
elog(ERROR, "can only be used to end recovery");
xlrec.end_time = GetCurrentTimestamp();
+ xlrec.wal_level = wal_level;
WALInsertLockAcquireExclusive();
xlrec.ThisTimeLineID = XLogCtl->InsertTimeLineID;
diff --git a/src/backend/postmaster/walsummarizer.c b/src/backend/postmaster/walsummarizer.c
index 55dc2ea8f53..83c178e7662 100644
--- a/src/backend/postmaster/walsummarizer.c
+++ b/src/backend/postmaster/walsummarizer.c
@@ -154,7 +154,8 @@ static void SummarizeSmgrRecord(XLogReaderState *xlogreader,
BlockRefTable *brtab);
static void SummarizeXactRecord(XLogReaderState *xlogreader,
BlockRefTable *brtab);
-static bool SummarizeXlogRecord(XLogReaderState *xlogreader);
+static bool SummarizeXlogRecord(XLogReaderState *xlogreader,
+ bool *new_fast_forward);
static int summarizer_read_local_xlog_page(XLogReaderState *state,
XLogRecPtr targetPagePtr,
int reqLen,
@@ -802,6 +803,7 @@ SummarizeWAL(TimeLineID tli, XLogRecPtr start_lsn, bool exact,
char final_path[MAXPGPATH];
WalSummaryIO io;
BlockRefTable *brtab = CreateEmptyBlockRefTable();
+ bool fast_forward = true;
/* Initialize private data for xlogreader. */
private_data = (SummarizerReadLocalXLogPrivate *)
@@ -900,7 +902,7 @@ SummarizeWAL(TimeLineID tli, XLogRecPtr start_lsn, bool exact,
int block_id;
char *errormsg;
XLogRecord *record;
- bool stop_requested = false;
+ uint8 rmid;
HandleWalSummarizerInterrupts();
@@ -969,56 +971,86 @@ SummarizeWAL(TimeLineID tli, XLogRecPtr start_lsn, bool exact,
break;
}
- /* Special handling for particular types of WAL records. */
- switch (XLogRecGetRmid(xlogreader))
- {
- case RM_DBASE_ID:
- SummarizeDbaseRecord(xlogreader, brtab);
- break;
- case RM_SMGR_ID:
- SummarizeSmgrRecord(xlogreader, brtab);
- break;
- case RM_XACT_ID:
- SummarizeXactRecord(xlogreader, brtab);
- break;
- case RM_XLOG_ID:
- stop_requested = SummarizeXlogRecord(xlogreader);
- break;
- default:
- break;
- }
-
/*
- * If we've been told that it's time to end this WAL summary file, do
- * so. As an exception, if there's nothing included in this WAL
- * summary file yet, then stopping doesn't make any sense, and we
- * should wait until the next stop point instead.
+ * Certain types of records require special handling. Redo points and
+ * shutdown checkpoints trigger creation of new summary files and can
+ * also cause us to enter or exit "fast forward" mode. Other types of
+ * records can require special updates to the block reference table.
*/
- if (stop_requested && xlogreader->ReadRecPtr > summary_start_lsn)
+ rmid = XLogRecGetRmid(xlogreader);
+ if (rmid == RM_XLOG_ID)
{
- summary_end_lsn = xlogreader->ReadRecPtr;
- break;
+ bool new_fast_forward;
+
+ /*
+ * If we've already processed some WAL records when we hit a redo
+ * point or shutdown checkpoint, then we stop summarization before
+ * including this record in the current file, so that it will be
+ * the first record in the next file.
+ *
+ * When we hit one of those record types as the first record in a
+ * file, we adjust our notion of whether we're fast-forwarding.
+ * Any WAL generated with wal_level=minimal must be skipped
+ * without actually generating any summary file, because an
+ * incremental backup that crosses such WAL would be unsafe.
+ */
+ if (SummarizeXlogRecord(xlogreader, &new_fast_forward))
+ {
+ if (xlogreader->ReadRecPtr > summary_start_lsn)
+ {
+ summary_end_lsn = xlogreader->ReadRecPtr;
+ break;
+ }
+ else
+ fast_forward = new_fast_forward;
+ }
+ }
+ else if (!fast_forward)
+ {
+ /*
+ * This switch handles record types that require extra updates to
+ * the contents of the block reference table.
+ */
+ switch (rmid)
+ {
+ case RM_DBASE_ID:
+ SummarizeDbaseRecord(xlogreader, brtab);
+ break;
+ case RM_SMGR_ID:
+ SummarizeSmgrRecord(xlogreader, brtab);
+ break;
+ case RM_XACT_ID:
+ SummarizeXactRecord(xlogreader, brtab);
+ break;
+ }
}
- /* Feed block references from xlog record to block reference table. */
- for (block_id = 0; block_id <= XLogRecMaxBlockId(xlogreader);
- block_id++)
+ /*
+ * If we're in fast-forward mode, we don't really need to do anything.
+ * Otherwise, feed block references from xlog record to block
+ * reference table.
+ */
+ if (!fast_forward)
{
- RelFileLocator rlocator;
- ForkNumber forknum;
- BlockNumber blocknum;
+ for (block_id = 0; block_id <= XLogRecMaxBlockId(xlogreader);
+ block_id++)
+ {
+ RelFileLocator rlocator;
+ ForkNumber forknum;
+ BlockNumber blocknum;
- if (!XLogRecGetBlockTagExtended(xlogreader, block_id, &rlocator,
- &forknum, &blocknum, NULL))
- continue;
+ if (!XLogRecGetBlockTagExtended(xlogreader, block_id, &rlocator,
+ &forknum, &blocknum, NULL))
+ continue;
- /*
- * As we do elsewhere, ignore the FSM fork, because it's not fully
- * WAL-logged.
- */
- if (forknum != FSM_FORKNUM)
- BlockRefTableMarkBlockModified(brtab, &rlocator, forknum,
- blocknum);
+ /*
+ * As we do elsewhere, ignore the FSM fork, because it's not
+ * fully WAL-logged.
+ */
+ if (forknum != FSM_FORKNUM)
+ BlockRefTableMarkBlockModified(brtab, &rlocator, forknum,
+ blocknum);
+ }
}
/* Update our notion of where this summary file ends. */
@@ -1047,9 +1079,10 @@ SummarizeWAL(TimeLineID tli, XLogRecPtr start_lsn, bool exact,
/*
* If a timeline switch occurs, we may fail to make any progress at all
* before exiting the loop above. If that happens, we don't write a WAL
- * summary file at all.
+ * summary file at all. We can also skip writing a file if we're in
+ * fast-forward mode.
*/
- if (summary_end_lsn > summary_start_lsn)
+ if (summary_end_lsn > summary_start_lsn && !fast_forward)
{
/* Generate temporary and final path name. */
snprintf(temp_path, MAXPGPATH,
@@ -1085,6 +1118,14 @@ SummarizeWAL(TimeLineID tli, XLogRecPtr start_lsn, bool exact,
durable_rename(temp_path, final_path, ERROR);
}
+ /* If we skipped a non-zero amount of WAL, log a debug message. */
+ if (summary_end_lsn > summary_start_lsn && fast_forward)
+ ereport(DEBUG1,
+ errmsg("skipped summarizing WAL on TLI %u from %X/%X to %X/%X",
+ tli,
+ LSN_FORMAT_ARGS(summary_start_lsn),
+ LSN_FORMAT_ARGS(summary_end_lsn)));
+
return summary_end_lsn;
}
@@ -1263,22 +1304,70 @@ SummarizeXactRecord(XLogReaderState *xlogreader, BlockRefTable *brtab)
/*
* Special handling for WAL records with RM_XLOG_ID.
+ *
+ * The return value is true if WAL summarization should stop before this
+ * record and false otherwise. When the return value is true,
+ * *new_fast_forward indicates whether future processing should be done
+ * in fast forward mode (i.e. read WAL without emitting summaries) or not.
*/
static bool
-SummarizeXlogRecord(XLogReaderState *xlogreader)
+SummarizeXlogRecord(XLogReaderState *xlogreader, bool *new_fast_forward)
{
uint8 info = XLogRecGetInfo(xlogreader) & ~XLR_INFO_MASK;
+ int record_wal_level;
- if (info == XLOG_CHECKPOINT_REDO || info == XLOG_CHECKPOINT_SHUTDOWN)
+ if (info == XLOG_CHECKPOINT_REDO)
{
- /*
- * This is an LSN at which redo might begin, so we'd like
- * summarization to stop just before this WAL record.
- */
- return true;
+ /* Payload is wal_level at the time record was written. */
+ memcpy(&record_wal_level, XLogRecGetData(xlogreader), sizeof(int));
}
+ else if (info == XLOG_CHECKPOINT_SHUTDOWN)
+ {
+ CheckPoint rec_ckpt;
- return false;
+ /* Extract wal_level at time record was written from payload. */
+ memcpy(&rec_ckpt, XLogRecGetData(xlogreader), sizeof(CheckPoint));
+ record_wal_level = rec_ckpt.wal_level;
+ }
+ else if (info == XLOG_PARAMETER_CHANGE)
+ {
+ xl_parameter_change xlrec;
+
+ /* Extract wal_level at time record was written from payload. */
+ memcpy(&xlrec, XLogRecGetData(xlogreader),
+ sizeof(xl_parameter_change));
+ record_wal_level = xlrec.wal_level;
+ }
+ else if (info == XLOG_END_OF_RECOVERY)
+ {
+ xl_end_of_recovery xlrec;
+
+ /* Extract wal_level at time record was written from payload. */
+ memcpy(&xlrec, XLogRecGetData(xlogreader), sizeof(xl_end_of_recovery));
+ record_wal_level = xlrec.wal_level;
+ }
+ else
+ {
+ /* No special handling required. Return false. */
+ return false;
+ }
+
+ /*
+ * Redo can only begin at an XLOG_CHECKPOINT_REDO or
+ * XLOG_CHECKPOINT_SHUTDOWN record, so we want WAL summarization to begin
+ * at those points. Hence, when those records are encountered, return
+ * true, so that we stop just before summarizing either of those records.
+ *
+ * We also reach here if we just saw XLOG_END_OF_RECOVERY or
+ * XLOG_PARAMETER_CHANGE. These are not places where recovery can start,
+ * but they're still relevant here. A new timeline can begin with
+ * XLOG_END_OF_RECOVERY, so we need to confirm the WAL level at that
+ * point; and a restart can provoke XLOG_PARAMETER_CHANGE after an
+ * intervening change to postgresql.conf, which might force us to stop
+ * summarizing.
+ */
+ *new_fast_forward = (record_wal_level == WAL_LEVEL_MINIMAL);
+ return true;
}
/*
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-04 20:41:13 +0000