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[PATCH v25 3/9] Row pattern recognition patch (rewriter).
324+ messages / 2 participants
[nested] [flat]

* [PATCH v25 3/9] Row pattern recognition patch (rewriter).
@ 2024-12-21 06:19 Tatsuo Ishii <ishii@postgresql.org>
  0 siblings, 0 replies; 324+ messages in thread

From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)

---
 src/backend/utils/adt/ruleutils.c | 103 ++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index be1f1f50b7..f58392f0aa 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -435,6 +435,10 @@ static void get_rule_groupingset(GroupingSet *gset, List *targetlist,
 								 bool omit_parens, deparse_context *context);
 static void get_rule_orderby(List *orderList, List *targetList,
 							 bool force_colno, deparse_context *context);
+static void get_rule_pattern(List *patternVariable, List *patternRegexp,
+							 bool force_colno, deparse_context *context);
+static void get_rule_define(List *defineClause, List *patternVariables,
+							bool force_colno, deparse_context *context);
 static void get_rule_windowclause(Query *query, deparse_context *context);
 static void get_rule_windowspec(WindowClause *wc, List *targetList,
 								deparse_context *context);
@@ -6667,6 +6671,67 @@ get_rule_orderby(List *orderList, List *targetList,
 	}
 }
 
+/*
+ * Display a PATTERN clause.
+ */
+static void
+get_rule_pattern(List *patternVariable, List *patternRegexp,
+				 bool force_colno, deparse_context *context)
+{
+	StringInfo	buf = context->buf;
+	const char *sep;
+	ListCell   *lc_var,
+			   *lc_reg = list_head(patternRegexp);
+
+	sep = "";
+	appendStringInfoChar(buf, '(');
+	foreach(lc_var, patternVariable)
+	{
+		char	   *variable = strVal((String *) lfirst(lc_var));
+		char	   *regexp = NULL;
+
+		if (lc_reg != NULL)
+		{
+			regexp = strVal((String *) lfirst(lc_reg));
+
+			lc_reg = lnext(patternRegexp, lc_reg);
+		}
+
+		appendStringInfo(buf, "%s%s", sep, variable);
+		if (regexp !=NULL)
+			appendStringInfoString(buf, regexp);
+
+		sep = " ";
+	}
+	appendStringInfoChar(buf, ')');
+}
+
+/*
+ * Display a DEFINE clause.
+ */
+static void
+get_rule_define(List *defineClause, List *patternVariables,
+				bool force_colno, deparse_context *context)
+{
+	StringInfo	buf = context->buf;
+	const char *sep;
+	ListCell   *lc_var,
+			   *lc_def;
+
+	sep = "  ";
+	Assert(list_length(patternVariables) == list_length(defineClause));
+
+	forboth(lc_var, patternVariables, lc_def, defineClause)
+	{
+		char	   *varName = strVal(lfirst(lc_var));
+		TargetEntry *te = (TargetEntry *) lfirst(lc_def);
+
+		appendStringInfo(buf, "%s%s AS ", sep, varName);
+		get_rule_expr((Node *) te->expr, context, false);
+		sep = ",\n  ";
+	}
+}
+
 /*
  * Display a WINDOW clause.
  *
@@ -6804,6 +6869,44 @@ get_rule_windowspec(WindowClause *wc, List *targetList,
 			appendStringInfoString(buf, "EXCLUDE GROUP ");
 		else if (wc->frameOptions & FRAMEOPTION_EXCLUDE_TIES)
 			appendStringInfoString(buf, "EXCLUDE TIES ");
+		/* RPR */
+		if (wc->rpSkipTo == ST_NEXT_ROW)
+			appendStringInfoString(buf,
+								   "\n  AFTER MATCH SKIP TO NEXT ROW ");
+		else if (wc->rpSkipTo == ST_PAST_LAST_ROW)
+			appendStringInfoString(buf,
+								   "\n  AFTER MATCH SKIP PAST LAST ROW ");
+		else if (wc->rpSkipTo == ST_FIRST_VARIABLE)
+			appendStringInfo(buf,
+							 "\n  AFTER MATCH SKIP TO FIRST %s ",
+							 wc->rpSkipVariable);
+		else if (wc->rpSkipTo == ST_LAST_VARIABLE)
+			appendStringInfo(buf,
+							 "\n  AFTER MATCH SKIP TO LAST %s ",
+							 wc->rpSkipVariable);
+		else if (wc->rpSkipTo == ST_VARIABLE)
+			appendStringInfo(buf,
+							 "\n  AFTER MATCH SKIP TO %s ",
+							 wc->rpSkipVariable);
+
+		if (wc->initial)
+			appendStringInfoString(buf, "\n  INITIAL");
+
+		if (wc->patternVariable)
+		{
+			appendStringInfoString(buf, "\n  PATTERN ");
+			get_rule_pattern(wc->patternVariable, wc->patternRegexp,
+							 false, context);
+		}
+
+		if (wc->defineClause)
+		{
+			appendStringInfoString(buf, "\n  DEFINE\n");
+			get_rule_define(wc->defineClause, wc->patternVariable,
+							false, context);
+			appendStringInfoChar(buf, ' ');
+		}
+
 		/* we will now have a trailing space; remove it */
 		buf->len--;
 	}
-- 
2.25.1


----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v25-0004-Row-pattern-recognition-patch-planner.patch"



^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 324+ messages in thread

From: Andres Freund @ 2026-04-07 13:11 UTC (permalink / raw)

The investigation into the negative test performance impact of 7e8aeb9e483
lead to discovering that there are a few issues with WAIT FOR.

This commit is just a minimal fix to prevent hangs in standby_flush mode, due
to WAIT FOR ... 'standby_flush' seeing a 0 LSN if a newly started walreceiver
does not receive any writes, because the stanby is already caught up.

There are several other issues and this is isn't necessarily the best fix. But
this way we get the hangs out of the way.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a437273cf9a..09fde92bfd7 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -242,8 +242,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
-
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 4e03e721872..bd5d47be964 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -321,6 +321,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 		walrcv->flushedUpto = recptr;
 		walrcv->receivedTLI = tli;
 		walrcv->latestChunkStart = recptr;
+		pg_atomic_write_u64(&walrcv->writtenUpto, recptr);
 	}
 	walrcv->receiveStart = recptr;
 	walrcv->receiveStartTLI = tli;
-- 
2.53.0.1.gb2826b52eb


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 324+ messages in thread