3 files changed, 45 insertions, 27 deletions

diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 78e39e5f866..ce6b5299324 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -185,8 +185,8 @@ PgArchShmemInit(void)
 /*
  * PgArchCanRestart
  *
- * Return true and archiver is allowed to restart if enough time has
- * passed since it was launched last to reach PGARCH_RESTART_INTERVAL.
+ * Return true, indicating archiver is allowed to restart, if enough time has
+ * passed since it was last launched to reach PGARCH_RESTART_INTERVAL.
  * Otherwise return false.
  *
  * This is a safety valve to protect against continuous respawn attempts if the
@@ -201,15 +201,18 @@ PgArchCanRestart(void)
 	time_t		curtime = time(NULL);
 
 	/*
-	 * Return false and don't restart archiver if too soon since last archiver
-	 * start.
+	 * If first time through, or time somehow went backwards, always update
+	 * last_pgarch_start_time to match the current clock and allow archiver
+	 * start.  Otherwise allow it only once enough time has elapsed.
 	 */
-	if ((unsigned int) (curtime - last_pgarch_start_time) <
-		(unsigned int) PGARCH_RESTART_INTERVAL)
-		return false;
-
-	last_pgarch_start_time = curtime;
-	return true;
+	if (last_pgarch_start_time == 0 ||
+		curtime < last_pgarch_start_time ||
+		curtime - last_pgarch_start_time >= PGARCH_RESTART_INTERVAL)
+	{
+		last_pgarch_start_time = curtime;
+		return true;
+	}
+	return false;
 }
 
 
@@ -332,7 +335,8 @@ pgarch_MainLoop(void)
 		 * SIGUSR2 arrives.  However, that means a random SIGTERM would
 		 * disable archiving indefinitely, which doesn't seem like a good
 		 * idea.  If more than 60 seconds pass since SIGTERM, exit anyway, so
-		 * that the postmaster can start a new archiver if needed.
+		 * that the postmaster can start a new archiver if needed.  Also exit
+		 * if time unexpectedly goes backward.
 		 */
 		if (ShutdownRequestPending)
 		{
@@ -340,8 +344,8 @@ pgarch_MainLoop(void)
 
 			if (last_sigterm_time == 0)
 				last_sigterm_time = curtime;
-			else if ((unsigned int) (curtime - last_sigterm_time) >=
-					 (unsigned int) 60)
+			else if (curtime < last_sigterm_time ||
+					 curtime - last_sigterm_time >= 60)
 				break;
 		}
 
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index e1d643b013d..00de559ba8f 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -1557,13 +1557,21 @@ DetermineSleepTime(void)
 	{
 		if (AbortStartTime != 0)
 		{
+			time_t		curtime = time(NULL);
 			int			seconds;
 
-			/* time left to abort; clamp to 0 in case it already expired */
-			seconds = SIGKILL_CHILDREN_AFTER_SECS -
-				(time(NULL) - AbortStartTime);
+			/*
+			 * time left to abort; clamp to 0 if it already expired, or if
+			 * time goes backwards
+			 */
+			if (curtime < AbortStartTime ||
+				curtime - AbortStartTime >= SIGKILL_CHILDREN_AFTER_SECS)
+				seconds = 0;
+			else
+				seconds = SIGKILL_CHILDREN_AFTER_SECS -
+					(curtime - AbortStartTime);
 
-			return Max(seconds * 1000, 0);
+			return seconds * 1000;
 		}
 		else
 			return 60 * 1000;
diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c
index 8c061d55bdb..b122d99b009 100644
--- a/src/backend/replication/logical/slotsync.c
+++ b/src/backend/replication/logical/slotsync.c
@@ -1636,8 +1636,9 @@ ShutDownSlotSync(void)
 /*
  * SlotSyncWorkerCanRestart
  *
- * Returns true if enough time (SLOTSYNC_RESTART_INTERVAL_SEC) has passed
- * since it was launched last. Otherwise returns false.
+ * Return true, indicating worker is allowed to restart, if enough time has
+ * passed since it was last launched to reach SLOTSYNC_RESTART_INTERVAL_SEC.
+ * Otherwise return false.
  *
  * This is a safety valve to protect against continuous respawn attempts if the
  * worker is dying immediately at launch. Note that since we will retry to
@@ -1649,14 +1650,19 @@ SlotSyncWorkerCanRestart(void)
 {
 	time_t		curtime = time(NULL);
 
-	/* Return false if too soon since last start. */
-	if ((unsigned int) (curtime - SlotSyncCtx->last_start_time) <
-		(unsigned int) SLOTSYNC_RESTART_INTERVAL_SEC)
-		return false;
-
-	SlotSyncCtx->last_start_time = curtime;
-
-	return true;
+	/*
+	 * If first time through, or time somehow went backwards, always update
+	 * last_start_time to match the current clock and allow worker start.
+	 * Otherwise allow it only once enough time has elapsed.
+	 */
+	if (SlotSyncCtx->last_start_time == 0 ||
+		curtime < SlotSyncCtx->last_start_time ||
+		curtime - SlotSyncCtx->last_start_time >= SLOTSYNC_RESTART_INTERVAL_SEC)
+	{
+		SlotSyncCtx->last_start_time = curtime;
+		return true;
+	}
+	return false;
 }
 
 /*