InnoDB: LOCK TABLE clean-up

innobase/include/lock0lock.h:
  Improve comments regarding LOCK_TABLE_EXP
innobase/include/row0mysql.h:
  Rename row_unlock_table_for_mysql() to row_unlock_tables_for_mysql()
  and improve its comment
innobase/include/trx0trx.h:
  Rename n_tables_locked to n_lock_table_exp
innobase/lock/lock0lock.c:
  Rename n_tables_locked to n_lock_table_exp
  Increment n_lock_table_exp already in lock_table_create()
  Replace some ut_ad() assertions with ut_a()
innobase/row/row0mysql.c:
  Rename n_tables_locked to n_lock_table_exp
  Rename row_unlock_table_for_mysql() to row_unlock_tables_for_mysql()
  and improve its comment
innobase/trx/trx0trx.c:
  Rename n_tables_locked to n_lock_table_exp
sql/ha_innodb.cc:
  Rename n_tables_locked to n_lock_table_exp
  Rename row_unlock_table_for_mysql() to row_unlock_tables_for_mysql()

innobase/include/lock0lock.h

@@ -418,7 +418,8 @@ lock_release_off_kernel(
 /*====================*/
 	trx_t*	trx);	/* in: transaction */
 /*************************************************************************
-Releases table locks, and releases possible other transactions waiting
+Releases table locks explicitly requested with LOCK TABLES (indicated by
+lock type LOCK_TABLE_EXP), and releases possible other transactions waiting
 because of these locks. */
 
 void
@@ -548,7 +549,7 @@ extern lock_sys_t*	lock_sys;
 /* Lock types */
 #define LOCK_TABLE	16	/* these type values should be so high that */
 #define	LOCK_REC	32	/* they can be ORed to the lock mode */
-#define LOCK_TABLE_EXP	80	/* explicit table lock */
+#define LOCK_TABLE_EXP	80	/* explicit table lock (80 = 16 + 64) */
 #define LOCK_TYPE_MASK	0xF0UL	/* mask used to extract lock type from the
 				type_mode field in a lock */
 /* Waiting lock flag */

innobase/include/row0mysql.h

@@ -153,11 +153,12 @@ row_lock_table_autoinc_for_mysql(
 	row_prebuilt_t*	prebuilt);	/* in: prebuilt struct in the MySQL
 					table handle */
 /*************************************************************************
-Unlocks a table lock possibly reserved by trx. */
+Unlocks all table locks explicitly requested by trx (with LOCK TABLES,
+lock type LOCK_TABLE_EXP). */
 
 void		  	
-row_unlock_table_for_mysql(
-/*=======================*/
+row_unlock_tables_for_mysql(
+/*========================*/
 	trx_t*	trx);	/* in: transaction */
 /*************************************************************************
 Sets a table lock on the table mentioned in prebuilt. */

innobase/include/trx0trx.h

@@ -423,8 +423,9 @@ struct trx_struct{
 	lock_t*		auto_inc_lock;	/* possible auto-inc lock reserved by
 					the transaction; note that it is also
 					in the lock list trx_locks */
-	ulint		n_tables_locked;/* number of table locks reserved by
-					the transaction, stored in trx_locks */
+	ulint		n_lock_table_exp;/* number of explicit table locks
+					(LOCK TABLES) reserved by the
+					transaction, stored in trx_locks */
 	UT_LIST_NODE_T(trx_t)
 			trx_list;	/* list of transactions */
 	UT_LIST_NODE_T(trx_t)

innobase/lock/lock0lock.c

@@ -2023,9 +2023,8 @@ lock_grant(
 
                 lock->trx->auto_inc_lock = lock;
         } else if (lock_get_type(lock) == LOCK_TABLE_EXP) {
-		ut_ad(lock_get_mode(lock) == LOCK_S
+		ut_a(lock_get_mode(lock) == LOCK_S
 			|| lock_get_mode(lock) == LOCK_X);
-		lock->trx->n_tables_locked++;
 	}
 
 	if (lock_print_waits) {
@@ -3203,6 +3202,10 @@ lock_table_create(
 	lock->type_mode = type_mode | LOCK_TABLE;
 	lock->trx = trx;
 
+	if ((lock->type_mode & LOCK_TABLE_EXP) == LOCK_TABLE_EXP) {
+		lock->trx->n_lock_table_exp++;
+	}
+
 	lock->un_member.tab_lock.table = table;
 
 	UT_LIST_ADD_LAST(un_member.tab_lock.locks, table->locks, lock);
@@ -3386,7 +3389,7 @@ lock_table(
 		return(DB_SUCCESS);
 	}
 
-	ut_ad(flags == 0 || flags == LOCK_TABLE_EXP);
+	ut_a(flags == 0 || flags == LOCK_TABLE_EXP);
 
 	trx = thr_get_trx(thr);
 
@@ -3418,10 +3421,7 @@ lock_table(
 
 	lock_table_create(table, mode | flags, trx);
 
-	if (flags) {
-		ut_ad(mode == LOCK_S || mode == LOCK_X);
-		trx->n_tables_locked++;
-	}
+	ut_a(!flags || mode == LOCK_S || mode == LOCK_X);
 
 	lock_mutex_exit_kernel();
 
@@ -3502,7 +3502,7 @@ lock_table_dequeue(
 #ifdef UNIV_SYNC_DEBUG
 	ut_ad(mutex_own(&kernel_mutex));
 #endif /* UNIV_SYNC_DEBUG */
-	ut_ad(lock_get_type(in_lock) == LOCK_TABLE ||
+	ut_a(lock_get_type(in_lock) == LOCK_TABLE ||
 		lock_get_type(in_lock) == LOCK_TABLE_EXP);
 
 	lock = UT_LIST_GET_NEXT(un_member.tab_lock.locks, in_lock);
@@ -3607,9 +3607,9 @@ lock_release_off_kernel(
 
 			lock_table_dequeue(lock);
 			if (lock_get_type(lock) == LOCK_TABLE_EXP) {
-				ut_ad(lock_get_mode(lock) == LOCK_S
+				ut_a(lock_get_mode(lock) == LOCK_S
 					|| lock_get_mode(lock) == LOCK_X);
-				trx->n_tables_locked--;
+				trx->n_lock_table_exp--;
 			}
 		}
 
@@ -3630,11 +3630,12 @@ lock_release_off_kernel(
 	mem_heap_empty(trx->lock_heap);
 
 	ut_a(trx->auto_inc_lock == NULL);
-	ut_a(trx->n_tables_locked == 0);
+	ut_a(trx->n_lock_table_exp == 0);
 }
 
 /*************************************************************************
-Releases table locks, and releases possible other transactions waiting
+Releases table locks explicitly requested with LOCK TABLES (indicated by
+lock type LOCK_TABLE_EXP), and releases possible other transactions waiting
 because of these locks. */
 
 void
@@ -3659,7 +3660,7 @@ lock_release_tables_off_kernel(
 		count++;
 
 		if (lock_get_type(lock) == LOCK_TABLE_EXP) {
-			ut_ad(lock_get_mode(lock) == LOCK_S
+			ut_a(lock_get_mode(lock) == LOCK_S
 				|| lock_get_mode(lock) == LOCK_X);
 			if (trx->insert_undo || trx->update_undo) {
 
@@ -3675,7 +3676,8 @@ lock_release_tables_off_kernel(
 			}
 
 			lock_table_dequeue(lock);
-			trx->n_tables_locked--;
+			trx->n_lock_table_exp--;
+
 			lock = UT_LIST_GET_LAST(trx->trx_locks);
 			continue;
 		}
@@ -3696,7 +3698,7 @@ lock_release_tables_off_kernel(
 
 	mem_heap_empty(trx->lock_heap);
 
-	ut_a(trx->n_tables_locked == 0);
+	ut_a(trx->n_lock_table_exp == 0);
 }
 
 /*************************************************************************

innobase/row/row0mysql.c

@@ -723,14 +723,15 @@ run_again:
 }
 
 /*************************************************************************
-Unlocks a table lock possibly reserved by trx. */
+Unlocks all table locks explicitly requested by trx (with LOCK TABLES,
+lock type LOCK_TABLE_EXP). */
 
 void		  	
-row_unlock_table_for_mysql(
-/*=======================*/
+row_unlock_tables_for_mysql(
+/*========================*/
 	trx_t*	trx)	/* in: transaction */
 {
-	if (!trx->n_tables_locked) {
+	if (!trx->n_lock_table_exp) {
 
 		return;
 	}

innobase/trx/trx0trx.c

@@ -151,7 +151,7 @@ trx_create(
 	trx->n_tickets_to_enter_innodb = 0;
 
 	trx->auto_inc_lock = NULL;
-	trx->n_tables_locked = 0;
+	trx->n_lock_table_exp = 0;
 	
 	trx->read_view_heap = mem_heap_create(256);
 	trx->read_view = NULL;
@@ -279,7 +279,7 @@ trx_free(
 
 	ut_a(!trx->has_search_latch);
 	ut_a(!trx->auto_inc_lock);
-	ut_a(!trx->n_tables_locked);
+	ut_a(!trx->n_lock_table_exp);
 
 	ut_a(trx->dict_operation_lock_mode == 0);
 

sql/ha_innodb.cc

@@ -4656,8 +4656,8 @@ ha_innobase::external_lock(
 	trx->n_mysql_tables_in_use--;
 	prebuilt->mysql_has_locked = FALSE;
 	auto_inc_counter_for_this_stat = 0;
-	if (trx->n_tables_locked) {
-		row_unlock_table_for_mysql(trx);
+	if (trx->n_lock_table_exp) {
+		row_unlock_tables_for_mysql(trx);
 	}
 
 	/* If the MySQL lock count drops to zero we know that the current SQL