2 files changed, 42 insertions, 0 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 1b7c2f23a41..b540ee293b6 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -4470,6 +4470,17 @@ LocalProcessControlFile(bool reset)
 }
 
 /*
+ * Get the wal_level from the control file. For a standby, this value should be
+ * considered as its active wal_level, because it may be different from what
+ * was originally configured on standby.
+ */
+WalLevel
+GetActiveWalLevelOnStandby(void)
+{
+	return ControlFile->wal_level;
+}
+
+/*
  * Initialization of shared memory for XLOG
  */
 Size
diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index c07daa874f9..52f827a902d 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -31,6 +31,7 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/smgr.h"
+#include "storage/standby.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
 #include "utils/memutils.h"
@@ -197,6 +198,36 @@ pg_switch_wal(PG_FUNCTION_ARGS)
 }
 
 /*
+ * pg_log_standby_snapshot: call LogStandbySnapshot()
+ *
+ * Permission checking for this function is managed through the normal
+ * GRANT system.
+ */
+Datum
+pg_log_standby_snapshot(PG_FUNCTION_ARGS)
+{
+	XLogRecPtr	recptr;
+
+	if (RecoveryInProgress())
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("recovery is in progress"),
+				 errhint("pg_log_standby_snapshot() cannot be executed during recovery.")));
+
+	if (!XLogStandbyInfoActive())
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("pg_log_standby_snapshot() can only be used if wal_level >= replica")));
+
+	recptr = LogStandbySnapshot();
+
+	/*
+	 * As a convenience, return the WAL location of the last inserted record
+	 */
+	PG_RETURN_LSN(recptr);
+}
+
+/*
  * pg_create_restore_point: a named point for restore
  *
  * Permission checking for this function is managed through the normal