From: Massimo Dal Zotto <dz@cs.unitn.it>

Subject: [HACKERS] lock debug trace

This is an update to my previous patches for lock debugging, already applied
to the current sources. It adds some improvements in the output messages and
some more output in WaitOnLock(). I have used with success to trace a nasty
deadlock condition on pg_listener.

src/backend/storage/lmgr/lock.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *    $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.8 1997/02/14 04:52:59 momjian Exp $
+ *    $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.9 1997/03/15 01:23:58 scrappy Exp $
  *
  * NOTES
  *    Outside modules can create a lock table and acquire/release
@@ -54,28 +54,41 @@
 
 #define LOCK_PRINT(where,tag,type)
 #define LOCK_DUMP(where,lock,type)
+#define LOCK_DUMP_AUX(where,lock,type)
 #define XID_PRINT(where,xidentP)
 
 #else /* LOCK_MGR_DEBUG */
 
 int lockDebug = 0;
+unsigned int lock_debug_oid_min = BootstrapObjectIdData;
+static char *lock_types[] = {
+    "NONE",
+    "WRITE",
+    "READ",
+    "WRITE INTENT",
+    "READ INTENT",
+    "EXTEND"
+};
 
 #define LOCK_PRINT(where,tag,type)\
-    if ((lockDebug >= 1) && (tag->relId >= BootstrapObjectIdData)) \
+    if ((lockDebug >= 1) && (tag->relId >= lock_debug_oid_min)) \
         elog(DEBUG, \
-	     "%s: pid (%d) rel (%d) dbid (%d) tid (%d,%d) type (%d)",where, \
+	     "%s: pid (%d) rel (%d) dbid (%d) tid (%d,%d) type (%s)",where, \
 	     getpid(),\
 	     tag->relId, tag->dbId, \
 	     ((tag->tupleId.ip_blkid.bi_hi<<16)+\
 	      tag->tupleId.ip_blkid.bi_lo),\
 	     tag->tupleId.ip_posid, \
-	     type);
+	     lock_types[type])
 
 #define LOCK_DUMP(where,lock,type)\
-    if ((lockDebug >= 1) && (lock->tag.relId >= BootstrapObjectIdData)) \
+    if ((lockDebug >= 1) && (lock->tag.relId >= lock_debug_oid_min)) \
+	LOCK_DUMP_AUX(where,lock,type)
+
+#define LOCK_DUMP_AUX(where,lock,type)\
         elog(DEBUG, \
 	     "%s: pid (%d) rel (%d) dbid (%d) tid (%d,%d) nHolding (%d) "\
-	     "holders (%d,%d,%d,%d,%d) type (%d)",where, \
+	     "holders (%d,%d,%d,%d,%d) type (%s)",where, \
 	     getpid(),\
 	     lock->tag.relId, lock->tag.dbId, \
 	     ((lock->tag.tupleId.ip_blkid.bi_hi<<16)+\
@@ -87,12 +100,12 @@ int lockDebug = 0;
 	     lock->holders[3],\
 	     lock->holders[4],\
 	     lock->holders[5],\
-	     type);
+	     lock_types[type])
 
 #define XID_PRINT(where,xidentP)\
     if ((lockDebug >= 2) && \
 	(((LOCK *)MAKE_PTR(xidentP->tag.lock))->tag.relId \
-	 >= BootstrapObjectIdData)) \
+	 >= lock_debug_oid_min)) \
 	elog(DEBUG,\
 	     "%s: pid (%d) xid (%d) pid (%d) lock (%x) nHolding (%d) "\
 	     "holders (%d,%d,%d,%d,%d)",\
@@ -106,7 +119,7 @@ int lockDebug = 0;
 	     xidentP->holders[2],\
 	     xidentP->holders[3],\
 	     xidentP->holders[4],\
-	     xidentP->holders[5]);
+	     xidentP->holders[5])
 
 #endif /* LOCK_MGR_DEBUG */
 
@@ -755,7 +768,7 @@ WaitOnLock(LOCKTAB *ltable, LockTableId tableId, LOCK *lock, LOCKT lockt)
      * will not be true if/when people can be deleted from
      * the queue by a SIGINT or something.
      */
-    LOCK_DUMP("WaitOnLock: sleeping on lock", lock, lockt);
+    LOCK_DUMP_AUX("WaitOnLock: sleeping on lock", lock, lockt);
     if (ProcSleep(waitQueue,
 		  ltable->ctl->masterLock,
 		  lockt,
@@ -770,11 +783,12 @@ WaitOnLock(LOCKTAB *ltable, LockTableId tableId, LOCK *lock, LOCKT lockt)
 	     */
 	    lock->nHolding--;
 	    lock->holders[lockt]--;
-	    LOCK_DUMP("WaitOnLock: aborting on lock", lock, lockt);
+	    LOCK_DUMP_AUX("WaitOnLock: aborting on lock", lock, lockt);
 	    SpinRelease(ltable->ctl->masterLock);
 	    elog(WARN,"WaitOnLock: error on wakeup - Aborting this transaction");
 	}
     
+    LOCK_DUMP_AUX("WaitOnLock: wakeup on lock", lock, lockt);
     return(STATUS_OK);
 }