Merging upstream version 15.6.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

5 files changed, 77 insertions, 12 deletions

diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 5293c69..ca7037e 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -486,7 +486,7 @@ MarkAsPreparingGuts(GlobalTransaction gxact, TransactionId xid, const char *gid,
 	proc->roleId = owner;
 	proc->tempNamespaceId = InvalidOid;
 	proc->isBackgroundWorker = false;
-	proc->lwWaiting = false;
+	proc->lwWaiting = LW_WS_NOT_WAITING;
 	proc->lwWaitMode = 0;
 	proc->waitLock = NULL;
 	proc->waitProcLock = NULL;
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index e0c7ad1..7a3d9b4 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -5265,6 +5265,7 @@ PushTransaction(void)
 	s->blockState = TBLOCK_SUBBEGIN;
 	GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
 	s->prevXactReadOnly = XactReadOnly;
+	s->startedInRecovery = p->startedInRecovery;
 	s->parallelModeLevel = 0;
 	s->topXidLogged = false;
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 59f94b0..9795ce7 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -974,8 +974,10 @@ XLogInsertRecord(XLogRecData *rdata,
 
 		if (!debug_reader)
 			debug_reader = XLogReaderAllocate(wal_segment_size, NULL,
-											  XL_ROUTINE(), NULL);
-
+											  XL_ROUTINE(.page_read = NULL,
+														 .segment_open = NULL,
+														 .segment_close = NULL),
+											  NULL);
 		if (!debug_reader)
 		{
 			appendStringInfoString(&buf, "error decoding record: out of memory while allocating a WAL reading processor");
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
index c15da9d..e7ad331 100644
--- a/src/backend/access/transam/xlogreader.c
+++ b/src/backend/access/transam/xlogreader.c
@@ -457,18 +457,37 @@ XLogReadRecordAlloc(XLogReaderState *state, size_t xl_tot_len, bool allow_oversi
 	if (state->decode_buffer_tail >= state->decode_buffer_head)
 	{
 		/* Empty, or tail is to the right of head. */
-		if (state->decode_buffer_tail + required_space <=
-			state->decode_buffer + state->decode_buffer_size)
+		if (required_space <=
+			state->decode_buffer_size -
+			(state->decode_buffer_tail - state->decode_buffer))
 		{
-			/* There is space between tail and end. */
+			/*-
+			 * There is space between tail and end.
+			 *
+			 * +-----+--------------------+-----+
+			 * |     |////////////////////|here!|
+			 * +-----+--------------------+-----+
+			 *       ^                    ^
+			 *       |                    |
+			 *       h                    t
+			 */
 			decoded = (DecodedXLogRecord *) state->decode_buffer_tail;
 			decoded->oversized = false;
 			return decoded;
 		}
-		else if (state->decode_buffer + required_space <
-				 state->decode_buffer_head)
+		else if (required_space <
+				 state->decode_buffer_head - state->decode_buffer)
 		{
-			/* There is space between start and head. */
+			/*-
+			 * There is space between start and head.
+			 *
+			 * +-----+--------------------+-----+
+			 * |here!|////////////////////|     |
+			 * +-----+--------------------+-----+
+			 *       ^                    ^
+			 *       |                    |
+			 *       h                    t
+			 */
 			decoded = (DecodedXLogRecord *) state->decode_buffer;
 			decoded->oversized = false;
 			return decoded;
@@ -477,10 +496,19 @@ XLogReadRecordAlloc(XLogReaderState *state, size_t xl_tot_len, bool allow_oversi
 	else
 	{
 		/* Tail is to the left of head. */
-		if (state->decode_buffer_tail + required_space <
-			state->decode_buffer_head)
+		if (required_space <
+			state->decode_buffer_head - state->decode_buffer_tail)
 		{
-			/* There is space between tail and head. */
+			/*-
+			 * There is space between tail and head.
+			 *
+			 * +-----+--------------------+-----+
+			 * |/////|here!               |/////|
+			 * +-----+--------------------+-----+
+			 *       ^                    ^
+			 *       |                    |
+			 *       t                    h
+			 */
 			decoded = (DecodedXLogRecord *) state->decode_buffer_tail;
 			decoded->oversized = false;
 			return decoded;
diff --git a/src/backend/access/transam/xlogrecovery.c b/src/backend/access/transam/xlogrecovery.c
index 166f7b7..1503b21 100644
--- a/src/backend/access/transam/xlogrecovery.c
+++ b/src/backend/access/transam/xlogrecovery.c
@@ -622,6 +622,22 @@ InitWalRecovery(ControlFileData *ControlFile, bool *wasShutdown_ptr,
 			EnableStandbyMode();
 
 		/*
+		 * Omitting backup_label when creating a new replica, PITR node etc.
+		 * unfortunately is a common cause of corruption.  Logging that
+		 * backup_label was used makes it a bit easier to exclude that as the
+		 * cause of observed corruption.
+		 *
+		 * Do so before we try to read the checkpoint record (which can fail),
+		 * as otherwise it can be hard to understand why a checkpoint other
+		 * than ControlFile->checkPoint is used.
+		 */
+		ereport(LOG,
+				(errmsg("starting backup recovery with redo LSN %X/%X, checkpoint LSN %X/%X, on timeline ID %u",
+						LSN_FORMAT_ARGS(RedoStartLSN),
+						LSN_FORMAT_ARGS(CheckPointLoc),
+						CheckPointTLI)));
+
+		/*
 		 * When a backup_label file is present, we want to roll forward from
 		 * the checkpoint it identifies, rather than using pg_control.
 		 */
@@ -759,6 +775,16 @@ InitWalRecovery(ControlFileData *ControlFile, bool *wasShutdown_ptr,
 				EnableStandbyMode();
 		}
 
+		/*
+		 * For the same reason as when starting up with backup_label present,
+		 * emit a log message when we continue initializing from a base
+		 * backup.
+		 */
+		if (!XLogRecPtrIsInvalid(ControlFile->backupStartPoint))
+			ereport(LOG,
+					(errmsg("restarting backup recovery with redo LSN %X/%X",
+							LSN_FORMAT_ARGS(ControlFile->backupStartPoint))));
+
 		/* Get the last valid checkpoint record. */
 		CheckPointLoc = ControlFile->checkPoint;
 		CheckPointTLI = ControlFile->checkPointCopy.ThisTimeLineID;
@@ -2102,6 +2128,9 @@ CheckRecoveryConsistency(void)
 	if (!XLogRecPtrIsInvalid(backupEndPoint) &&
 		backupEndPoint <= lastReplayedEndRecPtr)
 	{
+		XLogRecPtr	saveBackupStartPoint = backupStartPoint;
+		XLogRecPtr	saveBackupEndPoint = backupEndPoint;
+
 		elog(DEBUG1, "end of backup reached");
 
 		/*
@@ -2112,6 +2141,11 @@ CheckRecoveryConsistency(void)
 		backupStartPoint = InvalidXLogRecPtr;
 		backupEndPoint = InvalidXLogRecPtr;
 		backupEndRequired = false;
+
+		ereport(LOG,
+				(errmsg("completed backup recovery with redo LSN %X/%X and end LSN %X/%X",
+						LSN_FORMAT_ARGS(saveBackupStartPoint),
+						LSN_FORMAT_ARGS(saveBackupEndPoint))));
 	}
 
 	/*