diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 1cf88e953d..c5160fe907 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4173,11 +4173,11 @@ ANY num_sync ( ).
- The default is on. The only reason to turn this off would be if the
- remote instance is currently out of available replication slots. This
- parameter can only be set in the postgresql.conf
- file or on the server command line. Changes only take effect when the
- WAL receiver process starts a new connection.
+ The default is off. This parameter can only be set in the
+ postgresql.conf file or on the server command line.
+
+
+ The WAL receiver is restarted after an update of wal_receiver_create_temp_slot.
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index bbf8d4eee5..2ecb319438 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -290,6 +290,7 @@ bool StandbyModeRequested = false;
char *PrimaryConnInfo = NULL;
char *PrimarySlotName = NULL;
char *PromoteTriggerFile = NULL;
+bool wal_receiver_create_temp_slot = false;
/* are we currently in standby mode? */
bool StandbyMode = false;
@@ -12157,7 +12158,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
}
curFileTLI = tli;
RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
- PrimarySlotName);
+ PrimarySlotName, wal_receiver_create_temp_slot);
receivedUpto = 0;
}
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index f35b5adf7d..0dbf50934e 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -107,8 +107,10 @@ StartupRereadConfig(void)
{
char *conninfo = pstrdup(PrimaryConnInfo);
char *slotname = pstrdup(PrimarySlotName);
+ bool tempSlot = wal_receiver_create_temp_slot;
bool conninfoChanged;
bool slotnameChanged;
+ bool tempSlotChanged = false;
ProcessConfigFile(PGC_SIGHUP);
@@ -118,7 +120,14 @@ StartupRereadConfig(void)
pfree(conninfo);
pfree(slotname);
- if (conninfoChanged || slotnameChanged)
+ /*
+ * wal_receiver_create_temp_slot is used only when we have no slot
+ * configured. We do not need to track this change if it has no effect.
+ */
+ if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+ tempSlotChanged = tempSlot != wal_receiver_create_temp_slot;
+
+ if (conninfoChanged || slotnameChanged || tempSlotChanged)
StartupRequestWalReceiverRestart();
}
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index d11c957b15..0aa0c52c49 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -15,6 +15,12 @@
* WalRcv->receivedUpto variable in shared memory, to inform the startup
* process of how far it can proceed with XLOG replay.
*
+ * A WAL receiver cannot directly load GUC parameters used when establishing
+ * its connection to the primary. Instead it relies on parameter values
+ * that are passed down by the startup process when streaming is requested.
+ * This applies, for example, to the replication slot and the connection
+ * string to be used for the connection with the primary.
+ *
* If the primary server ends streaming, but doesn't disconnect, walreceiver
* goes into "waiting" mode, and waits for the startup process to give new
* instructions. The startup process will treat that the same as
@@ -74,7 +80,6 @@
/* GUC variables */
-bool wal_receiver_create_temp_slot;
int wal_receiver_status_interval;
int wal_receiver_timeout;
bool hot_standby_feedback;
@@ -349,42 +354,23 @@ WalReceiverMain(void)
WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
/*
- * Create temporary replication slot if no slot name is configured or
- * the slot from the previous run was temporary, unless
- * wal_receiver_create_temp_slot is disabled. We also need to handle
- * the case where the previous run used a temporary slot but
- * wal_receiver_create_temp_slot was changed in the meantime. In that
- * case, we delete the old slot name in shared memory. (This would
+ * Create temporary replication slot if requested. In that
+ * case, we update slot name in shared memory. (This would
* all be a bit easier if we just didn't copy the slot name into
* shared memory, since we won't need it again later, but then we
* can't see the slot name in the stats views.)
*/
- if (slotname[0] == '\0' || is_temp_slot)
+ if (is_temp_slot)
{
- bool changed = false;
+ snprintf(slotname, sizeof(slotname),
+ "pg_walreceiver_%lld",
+ (long long int) walrcv_get_backend_pid(wrconn));
- if (wal_receiver_create_temp_slot)
- {
- snprintf(slotname, sizeof(slotname),
- "pg_walreceiver_%lld",
- (long long int) walrcv_get_backend_pid(wrconn));
+ walrcv_create_slot(wrconn, slotname, true, 0, NULL);
- walrcv_create_slot(wrconn, slotname, true, 0, NULL);
- changed = true;
- }
- else if (slotname[0] != '\0')
- {
- slotname[0] = '\0';
- changed = true;
- }
-
- if (changed)
- {
- SpinLockAcquire(&walrcv->mutex);
- strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
- walrcv->is_temp_slot = wal_receiver_create_temp_slot;
- SpinLockRelease(&walrcv->mutex);
- }
+ SpinLockAcquire(&walrcv->mutex);
+ strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
+ SpinLockRelease(&walrcv->mutex);
}
/*
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 6926a7b514..21d1823607 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -215,13 +215,19 @@ ShutdownWalRcv(void)
/*
* Request postmaster to start walreceiver.
*
- * recptr indicates the position where streaming should begin, conninfo
- * is a libpq connection string to use, and slotname is, optionally, the name
- * of a replication slot to acquire.
+ * "recptr" indicates the position where streaming should begin. "conninfo"
+ * is a libpq connection string to use. "slotname" is, optionally, the name
+ * of a replication slot to acquire. "create_temp_slot" indicates to create
+ * a temporary slot when no "slotname" is given.
+ *
+ * WAL receivers do not directly load GUC parameters used for the connection
+ * to the primary, and rely on the values passed down by the caller of this
+ * routine instead. Hence, the addition of any new parameters should happen
+ * through this code path.
*/
void
RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
- const char *slotname)
+ const char *slotname, bool create_temp_slot)
{
WalRcvData *walrcv = WalRcv;
bool launch = false;
@@ -248,15 +254,22 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
else
walrcv->conninfo[0] = '\0';
- if (slotname != NULL)
+ /*
+ * Use configured replication slot if present, and ignore the value
+ * of create_temp_slot as the slot name should be persistent. Otherwise,
+ * use create_temp_slot to determine whether this WAL receiver should
+ * create a temporary slot by itself and use it, or not.
+ */
+ if (slotname != NULL && slotname[0] != '\0')
+ {
strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
+ walrcv->is_temp_slot = false;
+ }
else
+ {
walrcv->slotname[0] = '\0';
-
- /*
- * walreceiver will handle temporary slot by itself
- */
- walrcv->is_temp_slot = false;
+ walrcv->is_temp_slot = create_temp_slot;
+ }
if (walrcv->walRcvState == WALRCV_STOPPED)
{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c0b2b75407..53665971f5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2054,7 +2054,7 @@ static struct config_bool ConfigureNamesBool[] =
gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
},
&wal_receiver_create_temp_slot,
- true,
+ false,
NULL, NULL, NULL
},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index c4f2f881c9..f01e43b818 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -319,7 +319,8 @@
#max_standby_streaming_delay = 30s # max delay before canceling queries
# when reading streaming WAL;
# -1 allows indefinite delay
-#wal_receiver_create_temp_slot = on # create temp slot if primary_slot_name not set
+#wal_receiver_create_temp_slot = off # Create temp slot if primary_slot_name
+ # is not set.
#wal_receiver_status_interval = 10s # send replies at least this often
# 0 disables
#hot_standby_feedback = off # send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 42c4df0262..997db214cc 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -129,6 +129,7 @@ extern int recoveryTargetAction;
extern int recovery_min_apply_delay;
extern char *PrimaryConnInfo;
extern char *PrimarySlotName;
+extern bool wal_receiver_create_temp_slot;
/* indirectly set via GUC system */
extern TransactionId recoveryTargetXid;
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index e08afc6548..cf3e43128c 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -23,7 +23,6 @@
#include "utils/tuplestore.h"
/* user-settable parameters */
-extern bool wal_receiver_create_temp_slot;
extern int wal_receiver_status_interval;
extern int wal_receiver_timeout;
extern bool hot_standby_feedback;
@@ -321,7 +320,8 @@ extern void ShutdownWalRcv(void);
extern bool WalRcvStreaming(void);
extern bool WalRcvRunning(void);
extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr,
- const char *conninfo, const char *slotname);
+ const char *conninfo, const char *slotname,
+ bool create_temp_slot);
extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
extern int GetReplicationApplyDelay(void);
extern int GetReplicationTransferLatency(void);