Minor improvement in SI overflow logic: try to delete

expired messages before concluding that we really have buffer overflow.

diff --git a/src/backend/storage/ipc/sinvaladt.c b/src/backend/storage/ipc/sinvaladt.c
index 99426693cd1b8512e8ad1bc1691e5a13ee65241e..1a91dde9b1cf907c0f8ad9167a6bd16a8cd6dfb2 100644 (file)
--- a/src/backend/storage/ipc/sinvaladt.c
+++ b/src/backend/storage/ipc/sinvaladt.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.25 1999/09/06 19:37:38 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.26 1999/09/09 14:56:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -228,9 +228,19 @@ SIInsertDataEntry(SISeg *segP, SharedInvalidData *data)
        /* Is the buffer full? */
        if (numMsgs >= MAXNUMMESSAGES)
        {
-               /* Yes, so force reset */
-               SISetProcStateInvalid(segP);
-               return false;
+               /*
+                * Don't panic just yet: slowest backend might have consumed some
+                * messages but not yet have done SIDelExpiredDataEntries() to
+                * advance minMsgNum.  So, make sure minMsgNum is up-to-date.
+                */
+               SIDelExpiredDataEntries(segP);
+               numMsgs = segP->maxMsgNum - segP->minMsgNum;
+               if (numMsgs >= MAXNUMMESSAGES)
+               {
+                       /* Yup, it's definitely full, no choice but to reset */
+                       SISetProcStateInvalid(segP);
+                       return false;
+               }
        }
 
        /*