[Alvaro Herrera <alvherre@alvh.no-ip.org>]

On 2022-Apr-15, Tom Lane wrote:

> Here's a WIP patch for that.  The only exciting thing in it is that
> because of some undocumented cowboy programming in walsender.c, the
> 	Assert((proc->statusFlags & (~PROC_COPYABLE_FLAGS)) == 0);
> in ProcArrayInstallRestoredXmin fires unless we skip that.

Hmm, maybe a better use of that define is to use to select which flags
to copy, rather than to ensure we they are the only ones set.  What
about this?


-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"¿Qué importan los años?  Lo que realmente importa es comprobar que
a fin de cuentas la mejor edad de la vida es estar vivo"  (Mafalda)

Attachments:

copyflags.patch (text/x-diff, 1.1K) download
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 25c310f675..4347941568 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -2685,17 +2685,14 @@ ProcArrayInstallRestoredXmin(TransactionId xmin, PGPROC *proc)
 		TransactionIdIsNormal(xid) &&
 		TransactionIdPrecedesOrEquals(xid, xmin))
 	{
-		/* Install xmin */
+		/*
+		 * Install xmin.  In addition, propagate statusFlags that affect how
+		 * the value is interpreted by vacuum.
+		 */
 		MyProc->xmin = TransactionXmin = xmin;
 
-		/* walsender cheats by passing proc == MyProc, don't check its flags */
-		if (proc != MyProc)
-		{
-			/* Flags being copied must be valid copy-able flags. */
-			Assert((proc->statusFlags & (~PROC_COPYABLE_FLAGS)) == 0);
-			MyProc->statusFlags = proc->statusFlags;
-			ProcGlobal->statusFlags[MyProc->pgxactoff] = MyProc->statusFlags;
-		}
+		MyProc->statusFlags |= (proc->statusFlags & PROC_COPYABLE_FLAGS);
+		ProcGlobal->statusFlags[MyProc->pgxactoff] = MyProc->statusFlags;
 
 		result = true;
 	}