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[PATCH v3 3/3] Logical replication of DDL messages
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* [PATCH v3 3/3] Logical replication of DDL messages
@ 2022-03-18 17:17  Zheng (Zane) Li <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

From: Zheng (Zane) Li @ 2022-03-18 17:17 UTC (permalink / raw)

Integration with pgoutput:
Supports sending and receiving the DDL message using the logical
replication wire protocol. A new LogicalRepMsgType is introduced
for this purpose: LOGICAL_REP_MSG_DDLMESSAGE = 'L'.

Logical replication worker change:
Supports execution of the DDL command in the original user role and
search_path. For any new table created this way, we also set its
srsubstate in the pg_subscription_rel catalog to SUBREL_STATE_INIT,
So that DML replication can progress on this new table without
manually running "ALTER SUBSCRIPTION ... REFRESH PUBLICATION".

TAP test:
A new TAP test 030_rep_ddl.pl is added. We mainly focused on
testing the happy path of database level replication so far.
Corner case DDLs and table level DDL replication are still to be
carefully tested.
---
 src/backend/replication/logical/proto.c     |  63 ++++-
 src/backend/replication/logical/worker.c    | 264 ++++++++++++++++++++
 src/backend/replication/pgoutput/pgoutput.c |  69 ++++-
 src/include/replication/logicalproto.h      |  10 +-
 src/test/subscription/t/004_sync.pl         |   2 +-
 src/test/subscription/t/006_rewrite.pl      |   2 +-
 src/test/subscription/t/008_diff_schema.pl  |   2 +-
 src/test/subscription/t/009_matviews.pl     |   2 +-
 src/test/subscription/t/012_collation.pl    |   2 +-
 src/test/subscription/t/013_partition.pl    |   8 +-
 src/test/subscription/t/030_rep_ddls.pl     | 237 ++++++++++++++++++
 11 files changed, 646 insertions(+), 15 deletions(-)
 create mode 100644 src/test/subscription/t/030_rep_ddls.pl

diff --git a/src/backend/replication/logical/proto.c b/src/backend/replication/logical/proto.c
index c9b0eeefd7..762b897546 100644
--- a/src/backend/replication/logical/proto.c
+++ b/src/backend/replication/logical/proto.c
@@ -626,8 +626,8 @@ logicalrep_read_truncate(StringInfo in,
  */
 void
 logicalrep_write_message(StringInfo out, TransactionId xid, XLogRecPtr lsn,
-						 bool transactional, const char *prefix, Size sz,
-						 const char *message)
+						 bool transactional, const char *prefix,
+						 Size sz, const char *message)
 {
 	uint8		flags = 0;
 
@@ -648,6 +648,63 @@ logicalrep_write_message(StringInfo out, TransactionId xid, XLogRecPtr lsn,
 	pq_sendbytes(out, message, sz);
 }
 
+/*
+ * Read DDL MESSAGE from stream
+ */
+const char *
+logicalrep_read_ddlmessage(StringInfo in, XLogRecPtr *lsn,
+						   const char **prefix,
+						   const char **role,
+						   const char **search_path,
+						   bool *transactional,
+						   Size *sz)
+{
+	uint8 flags;
+	const char *msg;
+
+	//TODO double check when do we need to get TransactionId.
+
+	flags = pq_getmsgint(in, 1);
+	*transactional = (flags & MESSAGE_TRANSACTIONAL) > 0;
+	*lsn = pq_getmsgint64(in);
+	*prefix = pq_getmsgstring(in);
+	*role = pq_getmsgstring(in);
+	*search_path = pq_getmsgstring(in);
+	*sz = pq_getmsgint(in, 4);
+	msg = pq_getmsgbytes(in, *sz);
+
+	return msg;
+}
+
+/*
+ * Write DDL MESSAGE to stream
+ */
+void
+logicalrep_write_ddlmessage(StringInfo out, TransactionId xid, XLogRecPtr lsn,
+						 bool transactional, const char *prefix, const char *role,
+						 const char *search_path, Size sz, const char *message)
+{
+	uint8		flags = 0;
+
+	pq_sendbyte(out, LOGICAL_REP_MSG_DDLMESSAGE);
+
+	/* encode and send message flags */
+	if (transactional)
+		flags |= MESSAGE_TRANSACTIONAL;
+
+	/* transaction ID (if not valid, we're not streaming) */
+	if (TransactionIdIsValid(xid))
+		pq_sendint32(out, xid);
+
+	pq_sendint8(out, flags);
+	pq_sendint64(out, lsn);
+	pq_sendstring(out, prefix);
+	pq_sendstring(out, role);
+	pq_sendstring(out, search_path);
+	pq_sendint32(out, sz);
+	pq_sendbytes(out, message, sz);
+}
+
 /*
  * Write relation description to the output stream.
  */
@@ -1185,6 +1242,8 @@ logicalrep_message_type(LogicalRepMsgType action)
 			return "TYPE";
 		case LOGICAL_REP_MSG_MESSAGE:
 			return "MESSAGE";
+		case LOGICAL_REP_MSG_DDLMESSAGE:
+			return "DDL";
 		case LOGICAL_REP_MSG_BEGIN_PREPARE:
 			return "BEGIN PREPARE";
 		case LOGICAL_REP_MSG_PREPARE:
diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index 82dcffc2db..5972748b5e 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -156,6 +156,7 @@
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "optimizer/optimizer.h"
+#include "parser/analyze.h"
 #include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "postmaster/interrupt.h"
@@ -180,6 +181,8 @@
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "tcop/tcopprot.h"
+#include "tcop/pquery.h"
+#include "tcop/utility.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
 #include "utils/catcache.h"
@@ -346,6 +349,10 @@ static void apply_handle_tuple_routing(ApplyExecutionData *edata,
 									   TupleTableSlot *remoteslot,
 									   LogicalRepTupleData *newtup,
 									   CmdType operation);
+static void apply_execute_sql_command(const char *cmdstr,
+									  const char* role,
+									  const char* search_path,
+									  bool isTopLevel);
 
 /* Compute GID for two_phase transactions */
 static void TwoPhaseTransactionGid(Oid subid, TransactionId xid, char *gid, int szgid);
@@ -2446,6 +2453,259 @@ apply_handle_truncate(StringInfo s)
 	end_replication_step();
 }
 
+/*
+ * Handle generic messages.
+ */
+static void
+apply_handle_ddlmessage(StringInfo s)
+{
+	XLogRecPtr lsn;
+	bool transactional;
+	Size sz;
+	const char *prefix;
+	const char *role;
+	const char *search_path;
+	const char *msg;
+
+	msg = logicalrep_read_ddlmessage(s, &lsn, &prefix, &role, &search_path, &transactional, &sz);
+
+	apply_execute_sql_command(msg, role, search_path, true);
+}
+
+/*
+ * Add context to the errors produced by apply_execute_sql_command().
+ */
+static void
+execute_sql_command_error_cb(void *arg)
+{
+	errcontext("during execution of SQL statement: %s", (char *) arg);
+}
+
+/*
+ * Execute an SQL command. This can be multiple queries.
+ * This is modified based on pglogical_execute_sql_command().
+ */
+static void
+apply_execute_sql_command(const char *cmdstr, const char *role, const char *search_path,
+						  bool isTopLevel)
+{
+	const char *save_debug_query_string = debug_query_string;
+	List	   *parsetree_list;
+	ListCell   *parsetree_item;
+	MemoryContext oldcontext;
+	ErrorContextCallback errcallback;
+	int			save_nestlevel;
+
+	/*
+	 * Switch to appropriate context for constructing parsetrees.
+	 */
+	oldcontext = MemoryContextSwitchTo(ApplyMessageContext);
+	begin_replication_step();
+
+	/*
+	 * Set the current role to the user that executed the command on the
+	 * publication server.
+	 * Set the current search_path to the search_path on the publication
+	 * server when the command was executed.
+	 */
+	save_nestlevel = NewGUCNestLevel();
+	SetConfigOption("role", role, PGC_INTERNAL, PGC_S_OVERRIDE);
+	SetConfigOption("search_path", search_path, PGC_INTERNAL, PGC_S_OVERRIDE);
+
+	errcallback.callback = execute_sql_command_error_cb;
+	errcallback.arg = (char *) cmdstr;
+	errcallback.previous = error_context_stack;
+	error_context_stack = &errcallback;
+
+	debug_query_string = cmdstr;
+
+	parsetree_list = pg_parse_query(cmdstr);
+
+	/*
+	 * Do a limited amount of safety checking against CONCURRENTLY commands
+	 * executed in situations where they aren't allowed. The sender side should
+	 * provide protection, but better be safe than sorry.
+	 */
+	isTopLevel = isTopLevel && (list_length(parsetree_list) == 1);
+
+	/*
+	 * Switch back to transaction context to enter the loop.
+	 */
+	MemoryContextSwitchTo(oldcontext);
+
+	foreach(parsetree_item, parsetree_list)
+	{
+		List	   *plantree_list;
+		List	   *querytree_list;
+		RawStmt	   *command = (RawStmt *) lfirst(parsetree_item);
+		CommandTag	commandTag;
+		MemoryContext per_parsetree_context = NULL;
+		Portal		portal;
+		DestReceiver *receiver;
+		bool		 snapshot_set = false;
+		char 		 *schemaname = NULL; /* For CREATE TABLE stmt only */
+		char		 *relname = NULL; /* For CREATE TABLE stmt only */
+
+		commandTag = CreateCommandTag((Node *)command);
+
+		/*
+		 * Remember the schemaname and relname if it's a CREATE TABLE stmt
+		 * because we will need them for some post-processing after we
+		 * execute the stmt. At that point, CreateStmt may have been freeed up.
+		 */
+		if (commandTag == CMDTAG_CREATE_TABLE)
+		{
+			CreateStmt *cstmt = (CreateStmt *)command->stmt;
+			RangeVar *rv = cstmt->relation;
+			schemaname = rv->schemaname;
+			relname = rv->relname;
+		}
+
+		/*
+		 * Set up a snapshot if parse analysis/planning will need one.
+		 */
+		if (analyze_requires_snapshot(command))
+		{
+			PushActiveSnapshot(GetTransactionSnapshot());
+			snapshot_set = true;
+		}
+
+		/*
+		 * OK to analyze, rewrite, and plan this query.
+		 *
+		 * Switch to appropriate context for constructing query and plan trees
+		 * (these can't be in the transaction context, as that will get reset
+		 * when the command is COMMIT/ROLLBACK).  If we have multiple
+		 * parsetrees, we use a separate context for each one, so that we can
+		 * free that memory before moving on to the next one.  But for the
+		 * last (or only) parsetree, just use MessageContext, which will be
+		 * reset shortly after completion anyway.  In event of an error, the
+		 * per_parsetree_context will be deleted when MessageContext is reset.
+		 */
+		if (lnext(parsetree_list, parsetree_item) != NULL)
+		{
+			per_parsetree_context =
+				AllocSetContextCreate(MessageContext,
+									  "per-parsetree message context",
+									  ALLOCSET_DEFAULT_SIZES);
+			oldcontext = MemoryContextSwitchTo(per_parsetree_context);
+		}
+		else
+			oldcontext = MemoryContextSwitchTo(ApplyMessageContext);
+
+		querytree_list = pg_analyze_and_rewrite_fixedparams(
+			command,
+			cmdstr,
+			NULL, 0, NULL);
+
+		plantree_list = pg_plan_queries(
+			querytree_list, cmdstr, 0, NULL);
+
+		/*
+		 * Done with the snapshot used for parsing/planning.
+		 *
+		 * While it looks promising to reuse the same snapshot for query
+		 * execution (at least for simple protocol), unfortunately it causes
+		 * execution to use a snapshot that has been acquired before locking
+		 * any of the tables mentioned in the query.  This creates user-
+		 * visible anomalies, so refrain.  Refer to
+		 * https://postgr.es/m/flat/[email protected] for details.
+		 */
+		if (snapshot_set)
+			PopActiveSnapshot();
+
+		portal = CreatePortal("logical replication", true, true);
+
+		/*
+		 * We don't have to copy anything into the portal, because everything
+		 * we are passing here is in MessageContext or the
+		 * per_parsetree_context, and so will outlive the portal anyway.
+		 */
+		PortalDefineQuery(portal,
+						  NULL,
+						  cmdstr,
+						  commandTag,
+						  plantree_list,
+						  NULL);
+
+		/*
+		 * Start the portal.  No parameters here.
+		 */
+		PortalStart(portal, NULL, 0, InvalidSnapshot);
+
+		/* DestNone for logical replication */
+		receiver = CreateDestReceiver(DestNone);
+
+		/*
+		 * Switch back to transaction context for execution.
+		 */
+		MemoryContextSwitchTo(oldcontext);
+
+		(void) PortalRun(portal,
+						 FETCH_ALL,
+						 isTopLevel,
+						 true,
+						 receiver,
+						 receiver,
+						 NULL);
+		(*receiver->rDestroy) (receiver);
+
+		PortalDrop(portal, false);
+
+		CommandCounterIncrement();
+
+		/*
+		 * Table created by DDL replication (database level) is automatically
+		 * added to the subscription here.
+		 *
+		 * Call AddSubscriptionRelState for CREATE TABEL command to set
+		 * the relstate to SUBREL_STATE_INIT so DML changes on this
+		 * new table can be replicated without having to manually run
+		 * "alter subscription ... refresh publication"
+		 */
+		if (commandTag == CMDTAG_CREATE_TABLE)
+		{
+			Oid relid;
+			Oid relnamespace = InvalidOid;
+
+			if (schemaname != NULL)
+				relnamespace = get_namespace_oid(schemaname, false);
+			if (relnamespace != InvalidOid)
+				relid = get_relname_relid(relname, relnamespace);
+			else
+			{
+				/*
+				 * Try to resolve unqualified relname.
+				 * Notice we have set the search_path to the original search_path on the publisher
+				 * at the beginning of this function.
+				 */
+				relid = RelnameGetRelid(relname);
+			}
+
+			if (relid != InvalidOid)
+			{
+				AddSubscriptionRelState(MySubscription->oid, relid,
+										SUBREL_STATE_INIT,
+										InvalidXLogRecPtr);
+				ereport(DEBUG1,
+						(errmsg_internal("table \"%s\" added to subscription \"%s\"",
+										 relname, MySubscription->name)));
+			}
+		}
+	}
+
+	/*
+	 * Restore the GUC variables we set above.
+	 */
+	AtEOXact_GUC(true, save_nestlevel);
+
+	/* protect against stack resets during CONCURRENTLY processing */
+	if (error_context_stack == &errcallback)
+		error_context_stack = errcallback.previous;
+
+	debug_query_string = save_debug_query_string;
+	end_replication_step();
+}
 
 /*
  * Logical replication protocol message dispatcher.
@@ -2511,6 +2771,10 @@ apply_dispatch(StringInfo s)
 			 */
 			break;
 
+		case LOGICAL_REP_MSG_DDLMESSAGE:
+			apply_handle_ddlmessage(s);
+			break;
+
 		case LOGICAL_REP_MSG_STREAM_START:
 			apply_handle_stream_start(s);
 			break;
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 5fddab3a3d..ae9c92af2c 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -53,6 +53,10 @@ static void pgoutput_message(LogicalDecodingContext *ctx,
 							 ReorderBufferTXN *txn, XLogRecPtr message_lsn,
 							 bool transactional, const char *prefix,
 							 Size sz, const char *message);
+static void pgoutput_ddlmessage(LogicalDecodingContext *ctx,
+								ReorderBufferTXN *txn, XLogRecPtr message_lsn,
+								bool transactional, const char *prefix, const char *role,
+								const char *search_path, Size sz, const char *message);
 static bool pgoutput_origin_filter(LogicalDecodingContext *ctx,
 								   RepOriginId origin_id);
 static void pgoutput_begin_prepare_txn(LogicalDecodingContext *ctx,
@@ -208,6 +212,7 @@ _PG_output_plugin_init(OutputPluginCallbacks *cb)
 	cb->change_cb = pgoutput_change;
 	cb->truncate_cb = pgoutput_truncate;
 	cb->message_cb = pgoutput_message;
+	cb->ddlmessage_cb = pgoutput_ddlmessage;
 	cb->commit_cb = pgoutput_commit_txn;
 
 	cb->begin_prepare_cb = pgoutput_begin_prepare_txn;
@@ -224,6 +229,7 @@ _PG_output_plugin_init(OutputPluginCallbacks *cb)
 	cb->stream_commit_cb = pgoutput_stream_commit;
 	cb->stream_change_cb = pgoutput_change;
 	cb->stream_message_cb = pgoutput_message;
+	cb->stream_ddlmessage_cb = pgoutput_ddlmessage;
 	cb->stream_truncate_cb = pgoutput_truncate;
 	/* transaction streaming - two-phase commit */
 	cb->stream_prepare_cb = pgoutput_stream_prepare_txn;
@@ -1413,8 +1419,8 @@ pgoutput_truncate(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 
 static void
 pgoutput_message(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
-				 XLogRecPtr message_lsn, bool transactional, const char *prefix, Size sz,
-				 const char *message)
+				 XLogRecPtr message_lsn, bool transactional,
+				 const char *prefix, Size sz, const char *message)
 {
 	PGOutputData *data = (PGOutputData *) ctx->output_plugin_private;
 	TransactionId xid = InvalidTransactionId;
@@ -1440,6 +1446,57 @@ pgoutput_message(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 	OutputPluginWrite(ctx, true);
 }
 
+static void
+pgoutput_ddlmessage(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
+				 XLogRecPtr message_lsn, bool transactional,
+				 const char *prefix, const char * role,
+				 const char *search_path, Size sz, const char *message)
+{
+	PGOutputData *data = (PGOutputData *) ctx->output_plugin_private;
+	TransactionId xid = InvalidTransactionId;
+	ListCell *lc;
+
+	/* Reload publications if needed before use. */
+	if (!publications_valid)
+	{
+		MemoryContext oldctx = MemoryContextSwitchTo(CacheMemoryContext);
+		if (data->publications)
+			list_free_deep(data->publications);
+
+		data->publications = LoadPublications(data->publication_names);
+		MemoryContextSwitchTo(oldctx);
+		publications_valid = true;
+	}
+
+	/* Check if ddl replication is turned on for the publications */
+	foreach(lc, data->publications)
+	{
+		Publication *pub = (Publication *) lfirst(lc);
+		/* TODO need to check relid for table level DDLs */
+		if (!pub->pubactions.pubddl_database && !pub->pubactions.pubddl_table)
+			return;
+	}
+
+	/*
+	 * Remember the xid for the message in streaming mode. See
+	 * pgoutput_change.
+	 */
+	if (in_streaming)
+		xid = txn->xid;
+
+	OutputPluginPrepareWrite(ctx, true);
+	logicalrep_write_ddlmessage(ctx->out,
+							 xid,
+							 message_lsn,
+							 transactional,
+							 prefix,
+							 role,
+							 search_path,
+							 sz,
+							 message);
+	OutputPluginWrite(ctx, true);
+}
+
 /*
  * Currently we always forward.
  */
@@ -1725,7 +1782,9 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 		entry->schema_sent = false;
 		entry->streamed_txns = NIL;
 		entry->pubactions.pubinsert = entry->pubactions.pubupdate =
-			entry->pubactions.pubdelete = entry->pubactions.pubtruncate = false;
+			entry->pubactions.pubdelete = entry->pubactions.pubtruncate =
+			entry->pubactions.pubddl_database =
+			entry->pubactions.pubddl_table = false;
 		entry->new_slot = NULL;
 		entry->old_slot = NULL;
 		memset(entry->exprstate, 0, sizeof(entry->exprstate));
@@ -1780,6 +1839,8 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 		entry->pubactions.pubupdate = false;
 		entry->pubactions.pubdelete = false;
 		entry->pubactions.pubtruncate = false;
+		entry->pubactions.pubddl_database = false;
+		entry->pubactions.pubddl_table = false;
 
 		/*
 		 * Tuple slots cleanups. (Will be rebuilt later if needed).
@@ -1889,6 +1950,8 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 				entry->pubactions.pubupdate |= pub->pubactions.pubupdate;
 				entry->pubactions.pubdelete |= pub->pubactions.pubdelete;
 				entry->pubactions.pubtruncate |= pub->pubactions.pubtruncate;
+				entry->pubactions.pubddl_database |= pub->pubactions.pubddl_database;
+				entry->pubactions.pubddl_table |= pub->pubactions.pubddl_table;
 
 				/*
 				 * We want to publish the changes as the top-most ancestor
diff --git a/src/include/replication/logicalproto.h b/src/include/replication/logicalproto.h
index 4d2c881644..862ed467a6 100644
--- a/src/include/replication/logicalproto.h
+++ b/src/include/replication/logicalproto.h
@@ -61,6 +61,7 @@ typedef enum LogicalRepMsgType
 	LOGICAL_REP_MSG_RELATION = 'R',
 	LOGICAL_REP_MSG_TYPE = 'Y',
 	LOGICAL_REP_MSG_MESSAGE = 'M',
+	LOGICAL_REP_MSG_DDLMESSAGE = 'L',
 	LOGICAL_REP_MSG_BEGIN_PREPARE = 'b',
 	LOGICAL_REP_MSG_PREPARE = 'P',
 	LOGICAL_REP_MSG_COMMIT_PREPARED = 'K',
@@ -229,7 +230,14 @@ extern void logicalrep_write_truncate(StringInfo out, TransactionId xid,
 extern List *logicalrep_read_truncate(StringInfo in,
 									  bool *cascade, bool *restart_seqs);
 extern void logicalrep_write_message(StringInfo out, TransactionId xid, XLogRecPtr lsn,
-									 bool transactional, const char *prefix, Size sz, const char *message);
+									 bool transactional, const char *prefix,
+									 Size sz, const char *message);
+extern void logicalrep_write_ddlmessage(StringInfo out, TransactionId xid, XLogRecPtr lsn,
+										bool transactional, const char *prefix, const char *role,
+										const char *search_path, Size sz, const char *message);
+extern const char *logicalrep_read_ddlmessage(StringInfo in, XLogRecPtr *lsn, const char **prefix,
+											  const char **role, const char **search_path,
+											  bool *transactional, Size *sz);
 extern void logicalrep_write_rel(StringInfo out, TransactionId xid,
 								 Relation rel);
 extern LogicalRepRelation *logicalrep_read_rel(StringInfo in);
diff --git a/src/test/subscription/t/004_sync.pl b/src/test/subscription/t/004_sync.pl
index cf61fc1e0f..698c5114e6 100644
--- a/src/test/subscription/t/004_sync.pl
+++ b/src/test/subscription/t/004_sync.pl
@@ -33,7 +33,7 @@ $node_subscriber->safe_psql('postgres',
 # Setup logical replication
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 $node_publisher->safe_psql('postgres',
-	"CREATE PUBLICATION tap_pub FOR ALL TABLES");
+	"CREATE PUBLICATION tap_pub FOR ALL TABLES WITH (ddl = '')");
 
 $node_subscriber->safe_psql('postgres',
 	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub"
diff --git a/src/test/subscription/t/006_rewrite.pl b/src/test/subscription/t/006_rewrite.pl
index c924ff35f7..6c9b055eb0 100644
--- a/src/test/subscription/t/006_rewrite.pl
+++ b/src/test/subscription/t/006_rewrite.pl
@@ -23,7 +23,7 @@ $node_subscriber->safe_psql('postgres', $ddl);
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE PUBLICATION mypub FOR ALL TABLES;");
+	"CREATE PUBLICATION mypub FOR ALL TABLES WITH (ddl = '');");
 $node_subscriber->safe_psql('postgres',
 	"CREATE SUBSCRIPTION mysub CONNECTION '$publisher_connstr' PUBLICATION mypub;"
 );
diff --git a/src/test/subscription/t/008_diff_schema.pl b/src/test/subscription/t/008_diff_schema.pl
index 67b4026afa..2902e6fc34 100644
--- a/src/test/subscription/t/008_diff_schema.pl
+++ b/src/test/subscription/t/008_diff_schema.pl
@@ -32,7 +32,7 @@ $node_subscriber->safe_psql('postgres',
 # Setup logical replication
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 $node_publisher->safe_psql('postgres',
-	"CREATE PUBLICATION tap_pub FOR ALL TABLES");
+	"CREATE PUBLICATION tap_pub FOR ALL TABLES WITH (ddl = '')");
 
 $node_subscriber->safe_psql('postgres',
 	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub"
diff --git a/src/test/subscription/t/009_matviews.pl b/src/test/subscription/t/009_matviews.pl
index 1ce696d4a4..6c586877a1 100644
--- a/src/test/subscription/t/009_matviews.pl
+++ b/src/test/subscription/t/009_matviews.pl
@@ -19,7 +19,7 @@ $node_subscriber->start;
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE PUBLICATION mypub FOR ALL TABLES;");
+	"CREATE PUBLICATION mypub FOR ALL TABLES WITH (ddl = '');");
 $node_subscriber->safe_psql('postgres',
 	"CREATE SUBSCRIPTION mysub CONNECTION '$publisher_connstr' PUBLICATION mypub;"
 );
diff --git a/src/test/subscription/t/012_collation.pl b/src/test/subscription/t/012_collation.pl
index 2182f7948e..e1b5050663 100644
--- a/src/test/subscription/t/012_collation.pl
+++ b/src/test/subscription/t/012_collation.pl
@@ -76,7 +76,7 @@ $node_subscriber->safe_psql('postgres',
 # set up publication, subscription
 
 $node_publisher->safe_psql('postgres',
-	q{CREATE PUBLICATION pub1 FOR ALL TABLES});
+	q{CREATE PUBLICATION pub1 FOR ALL TABLES WITH (ddl = '')});
 
 $node_subscriber->safe_psql('postgres',
 	qq{CREATE SUBSCRIPTION sub1 CONNECTION '$publisher_connstr' PUBLICATION pub1 WITH (copy_data = false)}
diff --git a/src/test/subscription/t/013_partition.pl b/src/test/subscription/t/013_partition.pl
index 66e63e755e..de967eaaf2 100644
--- a/src/test/subscription/t/013_partition.pl
+++ b/src/test/subscription/t/013_partition.pl
@@ -25,9 +25,9 @@ $node_subscriber2->start;
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 # publisher
-$node_publisher->safe_psql('postgres', "CREATE PUBLICATION pub1");
+$node_publisher->safe_psql('postgres', "CREATE PUBLICATION pub1 WITH (ddl = '')");
 $node_publisher->safe_psql('postgres',
-	"CREATE PUBLICATION pub_all FOR ALL TABLES");
+	"CREATE PUBLICATION pub_all FOR ALL TABLES WITH (ddl = '')");
 $node_publisher->safe_psql('postgres',
 	"CREATE TABLE tab1 (a int PRIMARY KEY, b text) PARTITION BY LIST (a)");
 $node_publisher->safe_psql('postgres',
@@ -424,12 +424,12 @@ $node_publisher->safe_psql('postgres',
 # and child tables are present but changes will be replicated via the parent's
 # identity and only once.
 $node_publisher->safe_psql('postgres',
-	"CREATE PUBLICATION pub_viaroot FOR TABLE tab2, tab2_1, tab3_1 WITH (publish_via_partition_root = true)"
+	"CREATE PUBLICATION pub_viaroot FOR TABLE tab2, tab2_1, tab3_1 WITH (publish_via_partition_root = true, ddl = '')"
 );
 
 # for tab4, we publish changes through the "middle" partitioned table
 $node_publisher->safe_psql('postgres',
-	"CREATE PUBLICATION pub_lower_level FOR TABLE tab4_1 WITH (publish_via_partition_root = true)"
+	"CREATE PUBLICATION pub_lower_level FOR TABLE tab4_1 WITH (publish_via_partition_root = true, ddl = '')"
 );
 
 # prepare data for the initial sync
diff --git a/src/test/subscription/t/030_rep_ddls.pl b/src/test/subscription/t/030_rep_ddls.pl
new file mode 100644
index 0000000000..c88c4ea1c0
--- /dev/null
+++ b/src/test/subscription/t/030_rep_ddls.pl
@@ -0,0 +1,237 @@
+
+# Copyright (c) 2022, PostgreSQL Global Development Group
+
+# Regression tests for logical replication of DDLs
+use strict;
+use warnings;
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+my $node_publisher = PostgreSQL::Test::Cluster->new('publisher');
+$node_publisher->init(allows_streaming => 'logical');
+$node_publisher->append_conf('postgresql.conf', 'autovacuum = off');
+$node_publisher->start;
+
+my $node_subscriber = PostgreSQL::Test::Cluster->new('subscriber');
+$node_subscriber->init(allows_streaming => 'logical');
+$node_subscriber->append_conf('postgresql.conf', 'autovacuum = off');
+$node_subscriber->start;
+
+my $node_subscriber2 = PostgreSQL::Test::Cluster->new('subscriber2');
+$node_subscriber2->init(allows_streaming => 'logical');
+$node_subscriber2->append_conf('postgresql.conf', 'autovacuum = off');
+$node_subscriber2->start;
+
+my $ddl = "CREATE TABLE test_rep(id int primary key, name varchar);";
+$node_publisher->safe_psql('postgres', $ddl);
+$node_publisher->safe_psql('postgres', "INSERT INTO test_rep VALUES (1, 'data1');");
+$node_subscriber->safe_psql('postgres', $ddl);
+$node_subscriber2->safe_psql('postgres', $ddl);
+
+my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
+
+# mypub has pubddl_database on
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION mypub FOR ALL TABLES;");
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION mysub CONNECTION '$publisher_connstr' PUBLICATION mypub;"
+);
+# mypub2 has pubddl_database off
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION mypub2 FOR ALL TABLES with (ddl = '');");
+$node_subscriber2->safe_psql('postgres',
+	"CREATE SUBSCRIPTION mysub2 CONNECTION '$publisher_connstr' PUBLICATION mypub2;"
+);
+
+$node_publisher->wait_for_catchup('mysub');
+
+# Test simple CREATE TABLE command is replicated to subscriber
+# Test smae simple CREATE TABLE command is not replicated to subscriber2 (ddl off)
+# Test ALTER TABLE command is replicated on table test_rep
+# Test CREATE INDEX is replicated to subscriber
+# Test CREATE FUNCTION command is replicated to subscriber
+$node_publisher->safe_psql('postgres', "CREATE TABLE t1 (a int, b varchar);");
+$node_publisher->safe_psql('postgres', "ALTER TABLE test_rep ADD c3 int;");
+$node_publisher->safe_psql('postgres', "INSERT INTO test_rep VALUES (2, 'data2', 2);");
+$node_publisher->safe_psql('postgres', "CREATE INDEX nameindex on test_rep (name)");
+$node_publisher->safe_psql('postgres', qq{CREATE OR REPLACE FUNCTION totalRecords()
+RETURNS integer AS \$total\$
+declare
+	total integer;
+BEGIN
+   SELECT count(*) into total FROM test_rep;
+   RETURN total;
+END;
+\$total\$ LANGUAGE plpgsql;});
+
+$node_publisher->wait_for_catchup('mysub');
+
+my $result = $node_subscriber->safe_psql('postgres', "SELECT count(*) from t1");
+is($result, qq(0), 'CREATE of t1 replicated to subscriber');
+$result = $node_subscriber2->safe_psql('postgres', "SELECT count(*) from pg_tables where tablename = 't1';");
+is($result, qq(0), 'CREATE of t1 is not replicated to subscriber2');
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM test_rep WHERE c3 =2;");
+is($result, qq(1), 'ALTER test_rep ADD replicated');
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_class where relname = 'nameindex'");
+is($result, qq(1), 'CREATE INDEX nameindex replicated');
+$result = $node_subscriber->safe_psql('postgres', "SELECT totalRecords();");
+is($result, qq(2), 'CREATE of function totalRecords replicated to subscriber');
+$result = $node_subscriber2->safe_psql('postgres', "SELECT count(*) FROM pg_proc where proname = 'totalrecords';");
+is($result, qq(0), 'CREATE FUNCTION totalrecords is not replicated to subscriber2');
+
+# Test ALTER TABLE DROP
+# Test DROP INDEX
+# Test DROP FUNCTION
+$node_publisher->safe_psql('postgres', "ALTER TABLE test_rep DROP c3;");
+$node_publisher->safe_psql('postgres', "DELETE FROM test_rep where id = 2;");
+$node_publisher->safe_psql('postgres', "DROP INDEX nameindex;");
+$node_publisher->safe_psql('postgres', "DROP FUNCTION totalRecords;");
+
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) from test_rep;");
+is($result, qq(1), 'ALTER test_rep DROP replicated');
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_class where relname = 'nameindex'");
+is($result, qq(0), 'DROP INDEX nameindex replicated');
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_proc where proname = 'totalrecords';");
+is($result, qq(0), 'DROP FUNCTION totalrecords replicated');
+
+
+# TODO figure out how to set ON_ERROR_STOP = 0 in this test
+# Test failed CREATE/ALTER TABLE on publisher doesn't break replication
+# Table t1 already exits so expect the command to fail
+#$node_publisher->safe_psql('postgres', "CREATE TABLE t1 (a int, b varchar);");
+#$node_publisher->safe_psql('postgres', "ALTER TABLE test_rep DROP c3;");
+#$node_publisher->safe_psql('postgres', "INSERT INTO test_rep VALUES (103, 'data103', 1013);");
+
+#$node_publisher->wait_for_catchup('mysub');
+# Verify replication still works
+#$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) from test_rep;");
+#is($result, qq(1), 'DELETE from test_rep replicated');
+
+# Test DDLs inside txn block
+$node_publisher->safe_psql(
+	'postgres', q{
+BEGIN;
+CREATE TABLE t2 (a int, b varchar);
+ALTER TABLE test_rep ADD c3 int;
+INSERT INTO test_rep VALUES (3, 'data3', 3);
+COMMIT;});
+
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) from t2;");
+is($result, qq(0), 'CREATE t2 replicated');
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM test_rep;");
+is($result, qq(2), 'ALTER test_rep ADD replicated');
+
+# Test toggling pubddl_database option off
+$node_publisher->safe_psql('postgres', "ALTER PUBLICATION mypub set (ddl = '');");
+$result = $node_publisher->safe_psql('postgres', "SELECT pubddl_database, pubddl_table from pg_publication where pubname = 'mypub';");
+is($result, qq(f|f), 'pubddl_database turned off on mypub');
+$node_publisher->safe_psql('postgres', "CREATE TABLE t3 (a int, b varchar);");
+
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) from pg_tables where tablename = 't3';");
+is($result, qq(0), 'CREATE t3 is not replicated');
+
+# Test toggling pubddl_database option on
+$node_publisher->safe_psql('postgres', "ALTER PUBLICATION mypub set (ddl = 'database');");
+$result = $node_publisher->safe_psql('postgres', "SELECT pubddl_database, pubddl_table from pg_publication where pubname = 'mypub';");
+is($result, qq(t|t), 'pubddl_database turned on on mypub');
+
+$node_publisher->safe_psql('postgres', "CREATE TABLE t4 (a int, b varchar);");
+
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) from pg_tables where tablename = 't4';");
+is($result, qq(1), 'CREATE t4 is replicated');
+
+# Test DML changes on the new table t4 are replicated
+$node_publisher->safe_psql('postgres', "INSERT INTO t4 values (1, 'a')");
+$node_publisher->safe_psql('postgres', "INSERT INTO t4 values (2, 'b')");
+
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) from t4;");
+is($result, qq(2), 'DML Changes to t4 are replicated');
+
+# A somewhat complicated test in plpgsql block with trigger
+$node_publisher->safe_psql(
+	'postgres', q{
+BEGIN;
+CREATE TABLE foo (a int);
+CREATE INDEX foo_idx ON foo (a);
+ALTER TABLE foo ADD COLUMN b timestamptz;
+CREATE FUNCTION foo_ts()
+RETURNS trigger AS $$
+BEGIN
+NEW.b := current_timestamp;
+RETURN NEW;
+END;
+$$
+LANGUAGE plpgsql;
+CREATE TRIGGER foo_ts BEFORE INSERT OR UPDATE ON foo
+FOR EACH ROW EXECUTE FUNCTION foo_ts();
+INSERT INTO foo VALUES (1);
+COMMIT;});
+$result = $node_publisher->safe_psql('postgres', "SELECT b from foo where a = 1;");
+
+$node_publisher->wait_for_catchup('mysub');
+
+my $result_sub = $node_subscriber->safe_psql('postgres', "SELECT b from foo where a = 1;");
+is($result, qq($result_sub), 'timestamp of insert matches');
+
+# Test CREATE SCHEMA stmt is replicated
+$node_publisher->safe_psql('postgres', "CREATE SCHEMA s1");
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_catalog.pg_namespace WHERE nspname = 's1';");
+is($result, qq(1), 'CREATE SCHEMA s1 is replicated');
+
+# Test CREATE TABLE in new schema s1 followed by insert
+$node_publisher->safe_psql('postgres', "CREATE TABLE s1.t1 (a int, b varchar);");
+$node_publisher->safe_psql('postgres', "INSERT INTO s1.t1 VALUES (1, 'a');");
+$node_publisher->safe_psql('postgres', "INSERT INTO s1.t1 VALUES (2, 'b');");
+
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM s1.t1;");
+is($result, qq(2), 'CREATE TABLE s1.t1 is replicated');
+
+# Test replication works as expected with mismatched search_path on publisher and subscriber
+$node_publisher->append_conf('postgresql.conf', 'search_path = \'s1, public\'');
+$node_publisher->restart;
+# CREATE unqualified table t2, it is s1.t2 under the modified search_path
+$node_publisher->safe_psql('postgres', "CREATE TABLE t2 (a int, b varchar);");
+$node_publisher->safe_psql('postgres', "INSERT INTO t2 VALUES (1, 'a');");
+$node_publisher->safe_psql('postgres', "INSERT INTO t2 VALUES (2, 'b');");
+$node_publisher->safe_psql('postgres', "INSERT INTO t2 VALUES (3, 'c');");
+
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM s1.t2;");
+is($result, qq(3), 'CREATE TABLE s1.t2 is replicated');
+
+# Test owner of new table on subscriber matches the owner on publisher
+$node_publisher->safe_psql('postgres', "CREATE ROLE ddl_replication_user LOGIN SUPERUSER;");
+
+$node_subscriber->safe_psql('postgres', "CREATE ROLE ddl_replication_user LOGIN SUPERUSER;");
+
+$node_publisher->safe_psql('postgres', "SET SESSION AUTHORIZATION 'ddl_replication_user'; CREATE TABLE t5 (a int, b varchar);");
+$node_publisher->wait_for_catchup('mysub');
+
+$result = $node_subscriber->safe_psql('postgres', "SELECT tableowner from pg_catalog.pg_tables where tablename = 't5';");
+is($result, qq(ddl_replication_user), 'Owner of t5 is correct');
+
+#TODO TEST certain DDLs are not replicated
+
+pass "DDL replication tests passed!";
+
+$node_subscriber->stop;
+$node_subscriber2->stop;
+$node_publisher->stop;
+
+done_testing();
-- 
2.25.1


--=-=-=--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

* [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush'
@ 2026-04-07 13:11  Andres Freund <[email protected]>
  0 siblings, 0 replies; 64+ messages in thread

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

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

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

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

Reported-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/zqbppucpmkeqecfy4s5kscnru4tbk6khp3ozqz6ad2zijz354k@w4bdf4z3wqoz
---
 src/backend/replication/walreceiver.c      | 2 --
 src/backend/replication/walreceiverfuncs.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

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


--ags3ltqh73mz7p2n--





^ permalink  raw  reply  [nested|flat] 64+ messages in thread

end of thread, other threads:[~2026-04-07 13:11 UTC | newest]

Thread overview: 64+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2022-03-18 17:17 [PATCH v3 3/3] Logical replication of DDL messages Zheng (Zane) Li <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>
2026-04-07 13:11 [PATCH v1] Minimal fix for WAIT FOR ... MODE 'standby_flush' Andres Freund <[email protected]>

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