Re: Introduce XID age and inactive timeout based replication slot invalidation

Hi Nisha, here are a couple of review comments for patch v52-0001.

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Commit Message

Add check if slot is already acquired, then mark it invalidate directly.

~

/slot/the slot/

"mark it invalidate" ?

Maybe you meant:
"then invalidate it directly", or
"then mark it 'invalidated' directly", or
etc.

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src/backend/replication/logical/slotsync.c

1.
@@ -1508,7 +1508,7 @@ ReplSlotSyncWorkerMain(char *startup_data,
size_t startup_data_len)
static void
update_synced_slots_inactive_since(void)
{
- TimestampTz now = 0;
+ TimestampTz now;

/*
* We need to update inactive_since only when we are promoting standby to
@@ -1523,6 +1523,9 @@ update_synced_slots_inactive_since(void)
/* The slot sync worker or SQL function mustn't be running by now */
Assert((SlotSyncCtx->pid == InvalidPid) && !SlotSyncCtx->syncing);

+ /* Use same inactive_since time for all slots */
+ now = GetCurrentTimestamp();
+

Something is broken with these changes.

AFAICT, the result after applying patch 0001 still has code:
/* Use the same inactive_since time for all the slots. */
if (now == 0)
now = GetCurrentTimestamp();

So the end result has multiple/competing assignments to variable 'now'.

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Kind Regards,
Peter Smith.
Fujitsu Australia