This change includes optimization for a lock wait rules and a new behaviour for

a REPLACE command. 

1 files changed, 20 insertions, 16 deletions

diff --git a/innobase/lock/lock0lock.c b/innobase/lock/lock0lock.c
index 2ace0822a82..2d326f7392f 100644
--- a/innobase/lock/lock0lock.c
+++ b/innobase/lock/lock0lock.c
@@ -758,10 +758,10 @@ lock_rec_has_to_wait(
 	lock_t*	lock2,	/* in: another record lock; NOTE that it is assumed
 			that this has a lock bit set on the same record as
 			in the new lock we are setting */
-        ibool lock_is_on_supremum)  /* in: TRUE if we are setting the lock
-                                       on the 'supremum' record of an index page: we know
-                                       then that the lock request is really for a 'gap' type
-                                       lock */
+	ibool lock_is_on_supremum)  /* in: TRUE if we are setting the lock
+			on the 'supremum' record of an index
+			page: we know then that the lock request
+			is really for a 'gap' type lock */
 {
 	ut_ad(trx && lock2);
 	ut_ad(lock_get_type(lock2) == LOCK_REC);
@@ -773,15 +773,15 @@ lock_rec_has_to_wait(
 		/* We have somewhat complex rules when gap type record locks
 		cause waits */
 
-	        if( lock_is_on_supremum && !(type_mode & LOCK_INSERT_INTENTION))
-                {
-		        /* Lock on the supremum record is really a 'gap' type lock
-                           and gap type lock do not need to wait if it
-                           is not LOCK_INSERT_INTENSION type lock */
-
-                       return(FALSE);
-                }
-
+		if (( lock_is_on_supremum || (type_mode & LOCK_GAP))
+			&& !(type_mode & LOCK_INSERT_INTENTION)) {
+			/* Gap type locks without LOCK_INSERT_INTENTION flag
+			do not need to wait for anything. This is because different 
+			users can have conflicting lock types on gaps. */
+						  
+			return(FALSE);
+		}
+		
 		if ((type_mode & LOCK_REC_NOT_GAP)
 						&& lock_rec_get_gap(lock2)) {
 			/* Lock on just the record does not need to wait for
@@ -842,9 +842,12 @@ lock_has_to_wait(
 		if (lock_get_type(lock1) == LOCK_REC) {
 			ut_ad(lock_get_type(lock2) == LOCK_REC);
 
-
+			/* If this lock request is for a supremum record
+			then the second bit on the lock bitmap is set */
+			
 			return(lock_rec_has_to_wait(lock1->trx,
-			       lock1->type_mode, lock2,(ibool)lock_rec_get_nth_bit(lock1,1)));
+						lock1->type_mode, lock2,
+						lock_rec_get_nth_bit(lock1,1)));
 		}
 
 		return(TRUE);
@@ -1433,7 +1436,8 @@ lock_rec_other_has_conflicting(
 	lock = lock_rec_get_first(rec);
 
 	while (lock) {
-		if (lock_rec_has_to_wait(trx, mode, lock, (ibool)page_rec_is_supremum(rec))) {
+		if (lock_rec_has_to_wait(trx, mode, lock,
+			page_rec_is_supremum(rec))) {
 
 			return(lock);
 		}