Avoid unnecessary shared invalidations in ROLLBACK PREPARED

The performance gain is minimal, but this makes the logic more
consistent with AtEOXact_Inval().  No other invalidation is needed in
this case as PREPARE takes already care of sending any local ones.

Author: Liu Huailing
Reviewed-by: Tom Lane, Michael Paquier
Discussion: https://postgr.es/m/OSZPR01MB6215AA84D71EF2B3D354CF86BE139@OSZPR01MB6215.jpnprd01.prod.outlook.com

diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 6d3efb49a40a0dfcb63df224eef3f956c6b75ee0..2156de187c37fc99804078d8431405b0c0861e86 100644 (file)
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -1520,13 +1520,17 @@ FinishPreparedTransaction(const char *gid, bool isCommit)
     * Handle cache invalidation messages.
     *
     * Relcache init file invalidation requires processing both before and
-    * after we send the SI messages. See AtEOXact_Inval()
+    * after we send the SI messages, only when committing.  See
+    * AtEOXact_Inval().
     */
-   if (hdr->initfileinval)
-       RelationCacheInitFilePreInvalidate();
-   SendSharedInvalidMessages(invalmsgs, hdr->ninvalmsgs);
-   if (hdr->initfileinval)
-       RelationCacheInitFilePostInvalidate();
+   if (isCommit)
+   {
+       if (hdr->initfileinval)
+           RelationCacheInitFilePreInvalidate();
+       SendSharedInvalidMessages(invalmsgs, hdr->ninvalmsgs);
+       if (hdr->initfileinval)
+           RelationCacheInitFilePostInvalidate();
+   }
 
    /*
     * Acquire the two-phase lock.  We want to work on the two-phase callbacks