From 264b187aac17f0ce10e8748ea86fc967d08a0eb0 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 26 Dec 2019 17:17:25 +0900
Subject: [PATCH] Make sure to save updated physical slot.

Back to 11, changes of a physical repliation slot made by
pg_replication_slot_advance doesn't survive restart. The cause was
pg_physical_replication_slot_advance forgot to dirty the slot when
updated. Fix it.
---
 src/backend/replication/slot.c      | 19 +++++++++++++++++++
 src/backend/replication/slotfuncs.c | 10 ++++++++--
 src/include/replication/slot.h      |  1 +
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 21ae8531b3..40149d0d99 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -672,6 +672,25 @@ ReplicationSlotMarkDirty(void)
 	SpinLockRelease(&slot->mutex);
 }
 
+/*
+ * Return if the currently acquired slot is dirty.
+ */
+bool
+ReplicationSlotIsDirty(void)
+{
+	bool dirty;
+
+	ReplicationSlot *slot = MyReplicationSlot;
+
+	Assert(MyReplicationSlot != NULL);
+
+	SpinLockAcquire(&slot->mutex);
+	dirty = MyReplicationSlot->dirty;
+	SpinLockRelease(&slot->mutex);
+
+	return dirty;
+}
+
 /*
  * Convert a slot that's marked as RS_EPHEMERAL to a RS_PERSISTENT slot,
  * guaranteeing it will be there after an eventual crash.
diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c
index 6683fc3f9b..7b08ed691b 100644
--- a/src/backend/replication/slotfuncs.c
+++ b/src/backend/replication/slotfuncs.c
@@ -370,6 +370,13 @@ pg_physical_replication_slot_advance(XLogRecPtr moveto)
 		MyReplicationSlot->data.restart_lsn = moveto;
 		SpinLockRelease(&MyReplicationSlot->mutex);
 		retlsn = moveto;
+
+		/*
+         * We don't need to dirty the slot only for the above change, but dirty
+		 * this slot for the same reason with
+		 * pg_logical_replication_slot_advance.
+		 */
+		ReplicationSlotMarkDirty();
 	}
 
 	return retlsn;
@@ -574,9 +581,8 @@ pg_replication_slot_advance(PG_FUNCTION_ARGS)
 	nulls[0] = false;
 
 	/* Update the on disk state when lsn was updated. */
-	if (XLogRecPtrIsInvalid(endlsn))
+	if (ReplicationSlotIsDirty())
 	{
-		ReplicationSlotMarkDirty();
 		ReplicationSlotsComputeRequiredXmin(false);
 		ReplicationSlotsComputeRequiredLSN();
 		ReplicationSlotSave();
diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h
index 3a5763fb07..f76b84571f 100644
--- a/src/include/replication/slot.h
+++ b/src/include/replication/slot.h
@@ -189,6 +189,7 @@ extern void ReplicationSlotRelease(void);
 extern void ReplicationSlotCleanup(void);
 extern void ReplicationSlotSave(void);
 extern void ReplicationSlotMarkDirty(void);
+extern bool ReplicationSlotIsDirty(void);
 
 /* misc stuff */
 extern bool ReplicationSlotValidateName(const char *name, int elevel);
-- 
2.23.0