Date: Wed, 8 Jul 2026 22:10:55 -0500
From: Nathan Bossart <nathandbossart@gmail.com>
To: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Cc: pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Refactor how some aux processes advertise their ProcNumber
Message-ID: <ak8RP8xn5_H0BrJV@nathan>
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On Wed, Jul 08, 2026 at 05:43:01PM +0000, Heikki Linnakangas wrote:
> Switch to pg_atomic_uint32 for the fields. Seems easier to reason
> about than volatile pointers. There was some precedence for that, as
> were already using pg_atomic_uint32 for the procArrayGroupFirst and
> clogGroupFirst fields, which also store ProcNumbers.

Since removing volatile qualifiers is on my mind, I noticed that this patch
makes it possible to remove two more.  Patch attached.

-- 
nathan

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diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index a09d4097d51..f6351f1eb10 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -1114,8 +1114,7 @@ RequestCheckpoint(int flags)
 #define MAX_SIGNAL_TRIES 600	/* max wait 60.0 sec */
 	for (ntries = 0;; ntries++)
 	{
-		volatile PROC_HDR *procglobal = ProcGlobal;
-		ProcNumber	checkpointerProc = pg_atomic_read_u32(&procglobal->checkpointerProc);
+		ProcNumber	checkpointerProc = pg_atomic_read_u32(&ProcGlobal->checkpointerProc);
 
 		if (checkpointerProc == INVALID_PROC_NUMBER)
 		{
@@ -1536,8 +1535,7 @@ FirstCallSinceLastCheckpoint(void)
 void
 WakeupCheckpointer(void)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
-	ProcNumber	checkpointerProc = pg_atomic_read_u32(&procglobal->checkpointerProc);
+	ProcNumber	checkpointerProc = pg_atomic_read_u32(&ProcGlobal->checkpointerProc);
 
 	if (checkpointerProc != INVALID_PROC_NUMBER)
 		SetLatch(&GetPGProcByNumber(checkpointerProc)->procLatch);

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