Rename standby_slot_names to synchronized_standby_slots.

The standby_slot_names GUC allows the specification of physical standby
slots that must be synchronized before the logical walsenders associated
with logical failover slots. However, for this purpose, the GUC name is
too generic.

Author: Hou Zhijie
Reviewed-by: Bertrand Drouvot, Masahiko Sawada
Backpatch-through: 17
Discussion: https://postgr.es/m/ZnWeUgdHong93fQN@momjian.us

5 files changed, 69 insertions, 68 deletions

diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c
index 56d3fb5d0e5..94896aec284 100644
--- a/src/backend/replication/logical/slotsync.c
+++ b/src/backend/replication/logical/slotsync.c
@@ -620,8 +620,8 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid)
 	if (remote_slot->confirmed_lsn > latestFlushPtr)
 	{
 		/*
-		 * Can get here only if GUC 'standby_slot_names' on the primary server
-		 * was not configured correctly.
+		 * Can get here only if GUC 'synchronized_standby_slots' on the
+		 * primary server was not configured correctly.
 		 */
 		ereport(AmLogicalSlotSyncWorkerProcess() ? LOG : ERROR,
 				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 564cfee1270..baf9b89dc42 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -82,11 +82,11 @@ typedef struct ReplicationSlotOnDisk
 } ReplicationSlotOnDisk;
 
 /*
- * Struct for the configuration of standby_slot_names.
+ * Struct for the configuration of synchronized_standby_slots.
  *
  * Note: this must be a flat representation that can be held in a single chunk
  * of guc_malloc'd memory, so that it can be stored as the "extra" data for the
- * standby_slot_names GUC.
+ * synchronized_standby_slots GUC.
  */
 typedef struct
 {
@@ -97,7 +97,7 @@ typedef struct
 	 * slot_names contains 'nslotnames' consecutive null-terminated C strings.
 	 */
 	char		slot_names[FLEXIBLE_ARRAY_MEMBER];
-} StandbySlotNamesConfigData;
+} SyncStandbySlotsConfigData;
 
 /*
  * Lookup table for slot invalidation causes.
@@ -145,14 +145,14 @@ int			max_replication_slots = 10; /* the maximum number of replication
  * This GUC lists streaming replication standby server slot names that
  * logical WAL sender processes will wait for.
  */
-char	   *standby_slot_names;
+char	   *synchronized_standby_slots;
 
-/* This is the parsed and cached configuration for standby_slot_names */
-static StandbySlotNamesConfigData *standby_slot_names_config;
+/* This is the parsed and cached configuration for synchronized_standby_slots */
+static SyncStandbySlotsConfigData *synchronized_standby_slots_config;
 
 /*
  * Oldest LSN that has been confirmed to be flushed to the standbys
- * corresponding to the physical slots specified in the standby_slot_names GUC.
+ * corresponding to the physical slots specified in the synchronized_standby_slots GUC.
  */
 static XLogRecPtr ss_oldest_flush_lsn = InvalidXLogRecPtr;
 
@@ -2412,12 +2412,12 @@ GetSlotInvalidationCause(const char *invalidation_reason)
 }
 
 /*
- * A helper function to validate slots specified in GUC standby_slot_names.
+ * A helper function to validate slots specified in GUC synchronized_standby_slots.
  *
  * The rawname will be parsed, and the result will be saved into *elemlist.
  */
 static bool
-validate_standby_slots(char *rawname, List **elemlist)
+validate_sync_standby_slots(char *rawname, List **elemlist)
 {
 	bool		ok;
 
@@ -2472,17 +2472,17 @@ validate_standby_slots(char *rawname, List **elemlist)
 }
 
 /*
- * GUC check_hook for standby_slot_names
+ * GUC check_hook for synchronized_standby_slots
  */
 bool
-check_standby_slot_names(char **newval, void **extra, GucSource source)
+check_synchronized_standby_slots(char **newval, void **extra, GucSource source)
 {
 	char	   *rawname;
 	char	   *ptr;
 	List	   *elemlist;
 	int			size;
 	bool		ok;
-	StandbySlotNamesConfigData *config;
+	SyncStandbySlotsConfigData *config;
 
 	if ((*newval)[0] == '\0')
 		return true;
@@ -2491,7 +2491,7 @@ check_standby_slot_names(char **newval, void **extra, GucSource source)
 	rawname = pstrdup(*newval);
 
 	/* Now verify if the specified slots exist and have correct type */
-	ok = validate_standby_slots(rawname, &elemlist);
+	ok = validate_sync_standby_slots(rawname, &elemlist);
 
 	if (!ok || elemlist == NIL)
 	{
@@ -2500,15 +2500,15 @@ check_standby_slot_names(char **newval, void **extra, GucSource source)
 		return ok;
 	}
 
-	/* Compute the size required for the StandbySlotNamesConfigData struct */
-	size = offsetof(StandbySlotNamesConfigData, slot_names);
+	/* Compute the size required for the SyncStandbySlotsConfigData struct */
+	size = offsetof(SyncStandbySlotsConfigData, slot_names);
 	foreach_ptr(char, slot_name, elemlist)
 		size += strlen(slot_name) + 1;
 
 	/* GUC extra value must be guc_malloc'd, not palloc'd */
-	config = (StandbySlotNamesConfigData *) guc_malloc(LOG, size);
+	config = (SyncStandbySlotsConfigData *) guc_malloc(LOG, size);
 
-	/* Transform the data into StandbySlotNamesConfigData */
+	/* Transform the data into SyncStandbySlotsConfigData */
 	config->nslotnames = list_length(elemlist);
 
 	ptr = config->slot_names;
@@ -2526,10 +2526,10 @@ check_standby_slot_names(char **newval, void **extra, GucSource source)
 }
 
 /*
- * GUC assign_hook for standby_slot_names
+ * GUC assign_hook for synchronized_standby_slots
  */
 void
-assign_standby_slot_names(const char *newval, void *extra)
+assign_synchronized_standby_slots(const char *newval, void *extra)
 {
 	/*
 	 * The standby slots may have changed, so we must recompute the oldest
@@ -2537,19 +2537,19 @@ assign_standby_slot_names(const char *newval, void *extra)
 	 */
 	ss_oldest_flush_lsn = InvalidXLogRecPtr;
 
-	standby_slot_names_config = (StandbySlotNamesConfigData *) extra;
+	synchronized_standby_slots_config = (SyncStandbySlotsConfigData *) extra;
 }
 
 /*
- * Check if the passed slot_name is specified in the standby_slot_names GUC.
+ * Check if the passed slot_name is specified in the synchronized_standby_slots GUC.
  */
 bool
-SlotExistsInStandbySlotNames(const char *slot_name)
+SlotExistsInSyncStandbySlots(const char *slot_name)
 {
 	const char *standby_slot_name;
 
-	/* Return false if there is no value in standby_slot_names */
-	if (standby_slot_names_config == NULL)
+	/* Return false if there is no value in synchronized_standby_slots */
+	if (synchronized_standby_slots_config == NULL)
 		return false;
 
 	/*
@@ -2557,8 +2557,8 @@ SlotExistsInStandbySlotNames(const char *slot_name)
 	 * shouldn't hurt but if that turns out not to be true then we can cache
 	 * this information for each WalSender as well.
 	 */
-	standby_slot_name = standby_slot_names_config->slot_names;
-	for (int i = 0; i < standby_slot_names_config->nslotnames; i++)
+	standby_slot_name = synchronized_standby_slots_config->slot_names;
+	for (int i = 0; i < synchronized_standby_slots_config->nslotnames; i++)
 	{
 		if (strcmp(standby_slot_name, slot_name) == 0)
 			return true;
@@ -2570,7 +2570,7 @@ SlotExistsInStandbySlotNames(const char *slot_name)
 }
 
 /*
- * Return true if the slots specified in standby_slot_names have caught up to
+ * Return true if the slots specified in synchronized_standby_slots have caught up to
  * the given WAL location, false otherwise.
  *
  * The elevel parameter specifies the error level used for logging messages
@@ -2585,9 +2585,9 @@ StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel)
 
 	/*
 	 * Don't need to wait for the standbys to catch up if there is no value in
-	 * standby_slot_names.
+	 * synchronized_standby_slots.
 	 */
-	if (standby_slot_names_config == NULL)
+	if (synchronized_standby_slots_config == NULL)
 		return true;
 
 	/*
@@ -2611,8 +2611,8 @@ StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel)
 	 */
 	LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
 
-	name = standby_slot_names_config->slot_names;
-	for (int i = 0; i < standby_slot_names_config->nslotnames; i++)
+	name = synchronized_standby_slots_config->slot_names;
+	for (int i = 0; i < synchronized_standby_slots_config->nslotnames; i++)
 	{
 		XLogRecPtr	restart_lsn;
 		bool		invalidated;
@@ -2624,43 +2624,44 @@ StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel)
 		if (!slot)
 		{
 			/*
-			 * If a slot name provided in standby_slot_names does not exist,
-			 * report a message and exit the loop. A user can specify a slot
-			 * name that does not exist just before the server startup. The
-			 * GUC check_hook(validate_standby_slots) cannot validate such a
-			 * slot during startup as the ReplicationSlotCtl shared memory is
-			 * not initialized at that time. It is also possible for a user to
-			 * drop the slot in standby_slot_names afterwards.
+			 * If a slot name provided in synchronized_standby_slots does not
+			 * exist, report a message and exit the loop. A user can specify a
+			 * slot name that does not exist just before the server startup.
+			 * The GUC check_hook(validate_sync_standby_slots) cannot validate
+			 * such a slot during startup as the ReplicationSlotCtl shared
+			 * memory is not initialized at that time. It is also possible for
+			 * a user to drop the slot in synchronized_standby_slots
+			 * afterwards.
 			 */
 			ereport(elevel,
 					errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 					errmsg("replication slot \"%s\" specified in parameter %s does not exist",
-						   name, "standby_slot_names"),
+						   name, "synchronized_standby_slots"),
 					errdetail("Logical replication is waiting on the standby associated with \"%s\".",
 							  name),
 					errhint("Consider creating the slot \"%s\" or amend parameter %s.",
-							name, "standby_slot_names"));
+							name, "synchronized_standby_slots"));
 			break;
 		}
 
 		if (SlotIsLogical(slot))
 		{
 			/*
-			 * If a logical slot name is provided in standby_slot_names,
-			 * report a message and exit the loop. Similar to the non-existent
-			 * case, a user can specify a logical slot name in
-			 * standby_slot_names before the server startup, or drop an
-			 * existing physical slot and recreate a logical slot with the
-			 * same name.
+			 * If a logical slot name is provided in
+			 * synchronized_standby_slots, report a message and exit the loop.
+			 * Similar to the non-existent case, a user can specify a logical
+			 * slot name in synchronized_standby_slots before the server
+			 * startup, or drop an existing physical slot and recreate a
+			 * logical slot with the same name.
 			 */
 			ereport(elevel,
 					errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 					errmsg("cannot have logical replication slot \"%s\" in parameter %s",
-						   name, "standby_slot_names"),
+						   name, "synchronized_standby_slots"),
 					errdetail("Logical replication is waiting for correction on \"%s\".",
 							  name),
 					errhint("Consider removing logical slot \"%s\" from parameter %s.",
-							name, "standby_slot_names"));
+							name, "synchronized_standby_slots"));
 			break;
 		}
 
@@ -2676,11 +2677,11 @@ StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel)
 			ereport(elevel,
 					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					errmsg("physical slot \"%s\" specified in parameter %s has been invalidated",
-						   name, "standby_slot_names"),
+						   name, "synchronized_standby_slots"),
 					errdetail("Logical replication is waiting on the standby associated with \"%s\".",
 							  name),
 					errhint("Consider dropping and recreating the slot \"%s\" or amend parameter %s.",
-							name, "standby_slot_names"));
+							name, "synchronized_standby_slots"));
 			break;
 		}
 
@@ -2691,11 +2692,11 @@ StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel)
 				ereport(elevel,
 						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 						errmsg("replication slot \"%s\" specified in parameter %s does not have active_pid",
-							   name, "standby_slot_names"),
+							   name, "synchronized_standby_slots"),
 						errdetail("Logical replication is waiting on the standby associated with \"%s\".",
 								  name),
 						errhint("Consider starting standby associated with \"%s\" or amend parameter %s.",
-								name, "standby_slot_names"));
+								name, "synchronized_standby_slots"));
 
 			/* Continue if the current slot hasn't caught up. */
 			break;
@@ -2718,7 +2719,7 @@ StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel)
 	 * Return false if not all the standbys have caught up to the specified
 	 * WAL location.
 	 */
-	if (caught_up_slot_num != standby_slot_names_config->nslotnames)
+	if (caught_up_slot_num != synchronized_standby_slots_config->nslotnames)
 		return false;
 
 	/* The ss_oldest_flush_lsn must not retreat. */
@@ -2734,7 +2735,7 @@ StandbySlotsHaveCaughtup(XLogRecPtr wait_for_lsn, int elevel)
  * Wait for physical standbys to confirm receiving the given lsn.
  *
  * Used by logical decoding SQL functions. It waits for physical standbys
- * corresponding to the physical slots specified in the standby_slot_names GUC.
+ * corresponding to the physical slots specified in the synchronized_standby_slots GUC.
  */
 void
 WaitForStandbyConfirmation(XLogRecPtr wait_for_lsn)
@@ -2742,9 +2743,9 @@ WaitForStandbyConfirmation(XLogRecPtr wait_for_lsn)
 	/*
 	 * Don't need to wait for the standby to catch up if the current acquired
 	 * slot is not a logical failover slot, or there is no value in
-	 * standby_slot_names.
+	 * synchronized_standby_slots.
 	 */
-	if (!MyReplicationSlot->data.failover || !standby_slot_names_config)
+	if (!MyReplicationSlot->data.failover || !synchronized_standby_slots_config)
 		return;
 
 	ConditionVariablePrepareToSleep(&WalSndCtl->wal_confirm_rcv_cv);
@@ -2764,9 +2765,9 @@ WaitForStandbyConfirmation(XLogRecPtr wait_for_lsn)
 			break;
 
 		/*
-		 * Wait for the slots in the standby_slot_names to catch up, but use a
-		 * timeout (1s) so we can also check if the standby_slot_names has
-		 * been changed.
+		 * Wait for the slots in the synchronized_standby_slots to catch up,
+		 * but use a timeout (1s) so we can also check if the
+		 * synchronized_standby_slots has been changed.
 		 */
 		ConditionVariableTimedSleep(&WalSndCtl->wal_confirm_rcv_cv, 1000,
 									WAIT_EVENT_WAIT_FOR_STANDBY_CONFIRMATION);
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c623b07cf02..59d1dfc7e28 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1727,7 +1727,7 @@ WalSndUpdateProgress(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId
 
 /*
  * Wake up the logical walsender processes with logical failover slots if the
- * currently acquired physical slot is specified in standby_slot_names GUC.
+ * currently acquired physical slot is specified in synchronized_standby_slots GUC.
  */
 void
 PhysicalWakeupLogicalWalSnd(void)
@@ -1742,7 +1742,7 @@ PhysicalWakeupLogicalWalSnd(void)
 	if (RecoveryInProgress())
 		return;
 
-	if (SlotExistsInStandbySlotNames(NameStr(MyReplicationSlot->data.name)))
+	if (SlotExistsInSyncStandbySlots(NameStr(MyReplicationSlot->data.name)))
 		ConditionVariableBroadcast(&WalSndCtl->wal_confirm_rcv_cv);
 }
 
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 46c258be282..6f4188599b1 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -4692,7 +4692,7 @@ struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"standby_slot_names", PGC_SIGHUP, REPLICATION_PRIMARY,
+		{"synchronized_standby_slots", PGC_SIGHUP, REPLICATION_PRIMARY,
 			gettext_noop("Lists streaming replication standby server slot "
 						 "names that logical WAL sender processes will wait for."),
 			gettext_noop("Logical WAL sender processes will send decoded "
@@ -4700,9 +4700,9 @@ struct config_string ConfigureNamesString[] =
 						 "replication slots confirm receiving WAL."),
 			GUC_LIST_INPUT
 		},
-		&standby_slot_names,
+		&synchronized_standby_slots,
 		"",
-		check_standby_slot_names, assign_standby_slot_names, NULL
+		check_synchronized_standby_slots, assign_synchronized_standby_slots, NULL
 	},
 
 	/* End-of-list marker */
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index e0567de2190..9ec9f97e926 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -344,8 +344,8 @@
 				# method to choose sync standbys, number of sync standbys,
 				# and comma-separated list of application_name
 				# from standby(s); '*' = all
-#standby_slot_names = ''	# streaming replication standby server slot names that
-				# logical walsender processes will wait for
+#synchronized_standby_slots = ''	# streaming replication standby server slot
+				# names that logical walsender processes will wait for
 
 # - Standby Servers -