Adjust GetLockConflicts() so that it uses TopMemoryContext when

executed InHotStandby. Cleaner solution than using malloc or palloc
depending upon situation, as proposed by Tom.

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 2c024f8..cbc2070 100644 (file)
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/storage/lmgr/lock.c,v 1.192 2010/01/28 10:05:37 sriggs Exp $
+ *       $PostgreSQL: pgsql/src/backend/storage/lmgr/lock.c,v 1.193 2010/01/29 19:45:12 sriggs Exp $
  *
  * NOTES
  *       A lock table is a shared memory hash table.  When
@@ -1790,7 +1790,7 @@ LockReassignCurrentOwner(void)
 VirtualTransactionId *
 GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode)
 {
-       static VirtualTransactionId *vxids = NULL;
+       static VirtualTransactionId *vxids;
        LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
        LockMethod      lockMethodTable;
        LOCK       *lock;
@@ -1810,24 +1810,18 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode)
        /*
         * Allocate memory to store results, and fill with InvalidVXID.  We only
         * need enough space for MaxBackends + a terminator, since prepared xacts
-        * don't count.
+        * don't count. InHotStandby allocate once in TopMemoryContext.
         */
-       if (!InHotStandby)
-               vxids = (VirtualTransactionId *)
-                       palloc0(sizeof(VirtualTransactionId) * (MaxBackends + 1));
-       else
+       if (InHotStandby)
        {
                if (vxids == NULL)
-               {
                        vxids = (VirtualTransactionId *)
-                               malloc(sizeof(VirtualTransactionId) * (MaxBackends + 1));
-                       if (vxids == NULL)
-                               ereport(ERROR,
-                                       (errcode(ERRCODE_OUT_OF_MEMORY),
-                                        errmsg("out of memory")));
-
-               }
+                               MemoryContextAlloc(TopMemoryContext,
+                                       sizeof(VirtualTransactionId) * (MaxBackends + 1));
        }
+       else
+               vxids = (VirtualTransactionId *)
+                       palloc0(sizeof(VirtualTransactionId) * (MaxBackends + 1));
 
        /*
         * Look up the lock object matching the tag.