Widen the nLocks counts in local lock tables from int to int64. This

forestalls potential overflow when the same table (or other object, but
usually tables) is accessed by very many successive queries within a single
transaction.  Per report from Michael Milligan.

Back-patch to 8.0, which is as far back as the patch conveniently applies.
There have been no reports of overflow in pre-8.3 releases, but clearly the
risk existed all along.  (Michael's report suggests that 8.3 may consume lock
counts faster than prior releases, but with no test case to look at it's hard
to be sure about that.  Widening the counts seems a good future-proofing
measure in any event.)

diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h
index 2c86738e4de4884245d0a27b42fd594ada836a2b..d2bfb1115664c58f46a87e1f4f494936d4254de3 100644 (file)
--- a/src/include/storage/lock.h
+++ b/src/include/storage/lock.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.113 2008/05/12 00:00:54 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.114 2008/09/16 01:56:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -391,7 +391,7 @@ typedef struct LOCALLOCKOWNER
         * Must use a forward struct reference to avoid circularity.
         */
        struct ResourceOwnerData *owner;
-       int                     nLocks;                 /* # of times held by this owner */
+       int64           nLocks;                 /* # of times held by this owner */
 } LOCALLOCKOWNER;
 
 typedef struct LOCALLOCK
@@ -403,7 +403,7 @@ typedef struct LOCALLOCK
        LOCK       *lock;                       /* associated LOCK object in shared mem */
        PROCLOCK   *proclock;           /* associated PROCLOCK object in shmem */
        uint32          hashcode;               /* copy of LOCKTAG's hash value */
-       int                     nLocks;                 /* total number of times lock is held */
+       int64           nLocks;                 /* total number of times lock is held */
        int                     numLockOwners;  /* # of relevant ResourceOwners */
        int                     maxLockOwners;  /* allocated size of array */
        LOCALLOCKOWNER *lockOwners; /* dynamically resizable array */