Exit correctly from PrepareRedoRemove() when not found

Complex crash bug all started with this failure.
Diagnosed and fixed by Nikhil Sontakke, reviewed by me.

Reported-by: Jeff Janes
Author: Nikhil Sontakke
Discussion: https://postgr.es/m/CAMkU=1xBP8cqdS5eK8APHL=X6RHMMM2vG5g+QamduuTsyCwv9g@mail.gmail.com

diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 6e6678cfff69df7a50b27a2a02064a523a6086ea..49b6429218786a292baa7bf0827447934f2cde75 100644 (file)
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -2375,6 +2375,7 @@ PrepareRedoRemove(TransactionId xid, bool giveWarning)
 {
    GlobalTransaction gxact = NULL;
    int         i;
+   bool        found = false;
 
    Assert(RecoveryInProgress());
 
@@ -2386,6 +2387,7 @@ PrepareRedoRemove(TransactionId xid, bool giveWarning)
        if (gxact->xid == xid)
        {
            Assert(gxact->inredo);
+           found = true;
            break;
        }
    }
@@ -2394,7 +2396,7 @@ PrepareRedoRemove(TransactionId xid, bool giveWarning)
    /*
     * Just leave if there is nothing, this is expected during WAL replay.
     */
-   if (gxact == NULL)
+   if (!found)
        return;
 
    /*