Re: Consistently use the XLogRecPtrIsInvalid() macro

Álvaro Herrera <alvherre@kurilemu.de>

From: Álvaro Herrera <alvherre@kurilemu.de>

To: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

Cc: Peter Eisentraut <peter@eisentraut.org>, Michael Paquier <michael@paquier.xyz>, Heikki Linnakangas <hlinnaka@iki.fi>, Quan Zongliang <quanzongliang@yeah.net>, pgsql-hackers@lists.postgresql.org

Date: 2025-11-07T13:37:32Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Replace literal 0 with InvalidXLogRecPtr for XLogRecPtr assignments
- ec3174407164 19 (unreleased) landed
Replace pointer comparisons and assignments to literal zero with NULL
- ec782f56b0c3 19 (unreleased) landed
Use XLogRecPtrIsValid() in various places
- a2b02293bc65 19 (unreleased) landed
Introduce XLogRecPtrIsValid()
- d2965f627fe3 14.20 landed
- c0031d461324 18.1 landed
- 723cc84db50a 16.11 landed
- 49b45999f3b2 15.15 landed
- 33727aff18d0 17.7 landed
- 20bafb097288 13.23 landed
- 06edbed47862 19 (unreleased) landed

On 2025-Nov-07, Bertrand Drouvot wrote:

> Agree, will modify the .cocci scripts that way.

I just noticed that we missed this ... maybe you want to include it also?

diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index a0c79958fd5..1f11c8646f5 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -355,7 +355,7 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 	pg_read_barrier();
 	Assert(dlist_node_is_detached(&MyProc->syncRepLinks));
 	MyProc->syncRepState = SYNC_REP_NOT_WAITING;
-	MyProc->waitLSN = 0;
+	MyProc->waitLSN = InvalidXLogRecPtr;
 
 	/* reset ps display to remove the suffix */
 	if (update_process_title)
@@ -1028,7 +1028,7 @@ SyncRepQueueIsOrderedByLSN(int mode)
 
 	Assert(mode >= 0 && mode < NUM_SYNC_REP_WAIT_MODE);
 
-	lastLSN = 0;
+	lastLSN = InvalidXLogRecPtr;
 
 	dlist_foreach(iter, &WalSndCtl->SyncRepQueue[mode])
 	{
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 1504fafe6d8..ce0d6a7539c 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -509,7 +509,7 @@ InitProcess(void)
 	MyProc->recoveryConflictPending = false;
 
 	/* Initialize fields for sync rep */
-	MyProc->waitLSN = 0;
+	MyProc->waitLSN = InvalidXLogRecPtr;
 	MyProc->syncRepState = SYNC_REP_NOT_WAITING;
 	dlist_node_init(&MyProc->syncRepLinks);
 

> Now that XLogRecPtrIsValid() is available in back branches, I agree that we
> can be less conservative and not wait until v24. v21 looks like good timing to
> me.

Cool,  please resubmit.

-- 
Álvaro Herrera        Breisgau, Deutschland  —  https://www.EnterpriseDB.com/
"They proved that being American is not just for some people"
                                               (George Takei)