InnoDB: implement LOCK TABLE (Bug #3299)

innobase/include/lock0lock.h:
  Add lock_table_unlock() and lock_release_tables_off_kernel()
  Add LOCK_TABLE_EXP
innobase/include/row0mysql.h:
  Add row_unlock_table_for_mysql() and row_lock_table_for_mysql()
innobase/include/trx0trx.h:
  Add n_tables_locked
innobase/lock/lock0lock.c:
  Add LOCK_TABLE_EXP for explicit LOCK TABLE commands
  Add lock_table_unlock()
  Add lock_release_tables_off_kernel()
innobase/row/row0mysql.c:
  Add row_unlock_table_for_mysql() and row_lock_table_for_mysql()
innobase/trx/trx0trx.c:
  Add n_tables_locked
mysql-test/r/innodb.result:
  Updated handling of auto_inc columns
sql/ha_innodb.cc:
  Call row_lock_table_for_mysql() and row_unlock_table_for_mysql()

innobase/include/lock0lock.h

@@ -381,7 +381,9 @@ lock_table(
 				/* out: DB_SUCCESS, DB_LOCK_WAIT,
 				DB_DEADLOCK, or DB_QUE_THR_SUSPENDED */
 	ulint		flags,	/* in: if BTR_NO_LOCKING_FLAG bit is set,
-				does nothing */
+				does nothing;
+				if LOCK_TABLE_EXP bits are set,
+				creates an explicit table lock */
 	dict_table_t*	table,	/* in: database table in dictionary cache */
 	ulint		mode,	/* in: lock mode */
 	que_thr_t*	thr);	/* in: query thread */
@@ -394,6 +396,14 @@ lock_is_on_table(
 				/* out: TRUE if there are lock(s) */
 	dict_table_t*	table);	/* in: database table in dictionary cache */
 /*************************************************************************
+Releases a table lock.
+Releases possible other transactions waiting for this lock. */
+
+void
+lock_table_unlock(
+/*==============*/
+	lock_t*	lock);	/* in: lock */
+/*************************************************************************
 Releases an auto-inc lock a transaction possibly has on a table.
 Releases possible other transactions waiting for this lock. */
 
@@ -410,6 +420,14 @@ lock_release_off_kernel(
 /*====================*/
 	trx_t*	trx);	/* in: transaction */
 /*************************************************************************
+Releases table locks, and releases possible other transactions waiting
+because of these locks. */
+
+void
+lock_release_tables_off_kernel(
+/*===========================*/
+	trx_t*	trx);	/* in: transaction */
+/*************************************************************************
 Cancels a waiting lock request and releases possible other transactions
 waiting behind it. */
 
@@ -536,6 +554,7 @@ 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_TYPE_MASK	0xF0UL	/* mask used to extract lock type from the
 				type_mode field in a lock */
 /* Waiting lock flag */

innobase/include/row0mysql.h

@@ -153,6 +153,22 @@ 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. */
+
+void		  	
+row_unlock_table_for_mysql(
+/*=======================*/
+	trx_t*	trx);	/* in: transaction */
+/*************************************************************************
+Sets a table lock on the table mentioned in prebuilt. */
+
+int
+row_lock_table_for_mysql(
+/*=====================*/
+					/* out: error code or DB_SUCCESS */
+	row_prebuilt_t*	prebuilt);	/* in: prebuilt struct in the MySQL
+					table handle */
+/*************************************************************************
 Does an insert for MySQL. */
 
 int

innobase/include/trx0trx.h

@@ -421,6 +421,8 @@ 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 */
 	UT_LIST_NODE_T(trx_t)
 			trx_list;	/* list of transactions */
 	UT_LIST_NODE_T(trx_t)

innobase/lock/lock0lock.c

@@ -2001,7 +2001,11 @@ lock_grant(
                 release it at the end of the SQL statement */
 
                 lock->trx->auto_inc_lock = lock;
-        }
+        } else if (lock_get_type(lock) == LOCK_TABLE_EXP) {
+		ut_ad(lock_get_mode(lock) == LOCK_S
+			|| lock_get_mode(lock) == LOCK_X);
+		lock->trx->n_tables_locked++;
+	}
 
 #ifdef UNIV_DEBUG
 	if (lock_print_waits) {
@@ -2939,7 +2943,7 @@ retry:
 	}
 
 	if (ret == LOCK_VICTIM_IS_START) {
-		if (lock_get_type(lock) == LOCK_TABLE) {
+		if (lock_get_type(lock) & LOCK_TABLE) {
 			table = lock->un_member.tab_lock.table;
 			index = NULL;
 		} else {
@@ -3015,7 +3019,7 @@ lock_deadlock_recursive(
 	/* Look at the locks ahead of wait_lock in the lock queue */
 
 	for (;;) {
-		if (lock_get_type(lock) == LOCK_TABLE) {
+		if (lock_get_type(lock) & LOCK_TABLE) {
 
 			lock = UT_LIST_GET_PREV(un_member.tab_lock.locks, lock);
 		} else {
@@ -3347,7 +3351,9 @@ lock_table(
 				/* out: DB_SUCCESS, DB_LOCK_WAIT,
 				DB_DEADLOCK, or DB_QUE_THR_SUSPENDED */
 	ulint		flags,	/* in: if BTR_NO_LOCKING_FLAG bit is set,
-				does nothing */
+				does nothing;
+				if LOCK_TABLE_EXP bits are set,
+				creates an explicit table lock */
 	dict_table_t*	table,	/* in: database table in dictionary cache */
 	ulint		mode,	/* in: lock mode */
 	que_thr_t*	thr)	/* in: query thread */
@@ -3362,6 +3368,8 @@ lock_table(
 		return(DB_SUCCESS);
 	}
 
+	ut_ad(flags == 0 || flags == LOCK_TABLE_EXP);
+
 	trx = thr_get_trx(thr);
 
 	lock_mutex_enter_kernel();
@@ -3390,7 +3398,12 @@ lock_table(
 		return(err);
 	}
 
-	lock_table_create(table, mode, trx);
+	lock_table_create(table, mode | flags, trx);
+
+	if (flags) {
+		ut_ad(mode == LOCK_S || mode == LOCK_X);
+		trx->n_tables_locked++;
+	}
 
 	lock_mutex_exit_kernel();
 
@@ -3471,7 +3484,8 @@ 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_ad(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);
 
@@ -3495,6 +3509,22 @@ lock_table_dequeue(
 
 /*=========================== LOCK RELEASE ==============================*/
 
+/*************************************************************************
+Releases a table lock.
+Releases possible other transactions waiting for this lock. */
+
+void
+lock_table_unlock(
+/*==============*/
+	lock_t*	lock)	/* in: lock */
+{
+	mutex_enter(&kernel_mutex);
+
+	lock_table_dequeue(lock);
+
+	mutex_exit(&kernel_mutex);
+}
+
 /*************************************************************************
 Releases an auto-inc lock a transaction possibly has on a table.
 Releases possible other transactions waiting for this lock. */
@@ -3542,7 +3572,7 @@ lock_release_off_kernel(
 			
 			lock_rec_dequeue_from_page(lock);
 		} else {
-			ut_ad(lock_get_type(lock) == LOCK_TABLE);
+			ut_ad(lock_get_type(lock) & LOCK_TABLE);
 
 			if (lock_get_mode(lock) != LOCK_IS
 			    && (trx->insert_undo || trx->update_undo)) {
@@ -3558,6 +3588,11 @@ lock_release_off_kernel(
 			}
 
 			lock_table_dequeue(lock);
+			if (lock_get_type(lock) == LOCK_TABLE_EXP) {
+				ut_ad(lock_get_mode(lock) == LOCK_S
+					|| lock_get_mode(lock) == LOCK_X);
+				trx->n_tables_locked--;
+			}
 		}
 
 		if (count == LOCK_RELEASE_KERNEL_INTERVAL) {
@@ -3577,6 +3612,73 @@ lock_release_off_kernel(
 	mem_heap_empty(trx->lock_heap);
 
 	ut_a(trx->auto_inc_lock == NULL);
+	ut_a(trx->n_tables_locked == 0);
+}
+
+/*************************************************************************
+Releases table locks, and releases possible other transactions waiting
+because of these locks. */
+
+void
+lock_release_tables_off_kernel(
+/*===========================*/
+	trx_t*	trx)	/* in: transaction */
+{
+	dict_table_t*	table;
+	ulint		count;
+	lock_t*		lock;
+
+#ifdef UNIV_SYNC_DEBUG
+	ut_ad(mutex_own(&kernel_mutex));
+#endif /* UNIV_SYNC_DEBUG */
+
+	lock = UT_LIST_GET_LAST(trx->trx_locks);
+
+	count = 0;
+
+	while (lock != NULL) {
+
+		count++;
+
+		if (lock_get_type(lock) == LOCK_TABLE_EXP) {
+			ut_ad(lock_get_mode(lock) == LOCK_S
+				|| lock_get_mode(lock) == LOCK_X);
+			if (trx->insert_undo || trx->update_undo) {
+
+				/* The trx may have modified the table.
+				We block the use of the MySQL query
+				cache for all currently active
+				transactions. */
+
+				table = lock->un_member.tab_lock.table;
+
+				table->query_cache_inv_trx_id =
+							trx_sys->max_trx_id;
+			}
+
+			lock_table_dequeue(lock);
+			trx->n_tables_locked--;
+			lock = UT_LIST_GET_LAST(trx->trx_locks);
+			continue;
+		}
+
+		if (count == LOCK_RELEASE_KERNEL_INTERVAL) {
+			/* Release the kernel mutex for a while, so that we
+			do not monopolize it */
+
+			lock_mutex_exit_kernel();
+
+			lock_mutex_enter_kernel();
+
+			count = 0;
+		}
+
+		lock = UT_LIST_GET_PREV(trx_locks, lock);
+	}
+
+	mem_heap_empty(trx->lock_heap);
+
+	ut_a(trx->n_tables_locked == 0);
 }
 
 /*************************************************************************
@@ -3596,7 +3698,7 @@ lock_cancel_waiting_and_release(
 			
 		lock_rec_dequeue_from_page(lock);
 	} else {
-		ut_ad(lock_get_type(lock) == LOCK_TABLE);
+		ut_ad(lock_get_type(lock) & LOCK_TABLE);
 
 		lock_table_dequeue(lock);
 	}
@@ -3637,7 +3739,7 @@ lock_reset_all_on_table_for_trx(
 			ut_a(!lock_get_wait(lock));
 			
 			lock_rec_discard(lock);
-		} else if (lock_get_type(lock) == LOCK_TABLE
+		} else if (lock_get_type(lock) & LOCK_TABLE
 				&& lock->un_member.tab_lock.table == table) {
 
 			ut_a(!lock_get_wait(lock));
@@ -3689,8 +3791,12 @@ lock_table_print(
 #ifdef UNIV_SYNC_DEBUG
 	ut_ad(mutex_own(&kernel_mutex));
 #endif /* UNIV_SYNC_DEBUG */
-	ut_a(lock_get_type(lock) == LOCK_TABLE);
+	ut_a(lock_get_type(lock) == LOCK_TABLE ||
+		lock_get_type(lock) == LOCK_TABLE_EXP);
 
+	if (lock_get_type(lock) == LOCK_TABLE_EXP) {
+		fputs("EXPLICIT ", file);
+	}
 	fputs("TABLE LOCK table ", file);
 	ut_print_name(file, lock->un_member.tab_lock.table->name);
 	fprintf(file, " trx id %lu %lu",
@@ -4009,7 +4115,7 @@ loop:
 		
 		lock_rec_print(file, lock);
 	} else {
-		ut_ad(lock_get_type(lock) == LOCK_TABLE);
+		ut_ad(lock_get_type(lock) & LOCK_TABLE);
 	
 		lock_table_print(file, lock);
 	}
@@ -4290,7 +4396,7 @@ lock_validate(void)
 		lock = UT_LIST_GET_FIRST(trx->trx_locks);
 		
 		while (lock) {
-			if (lock_get_type(lock) == LOCK_TABLE) {
+			if (lock_get_type(lock) & LOCK_TABLE) {
 	
 				lock_table_queue_validate(
 					lock->un_member.tab_lock.table);

innobase/row/row0mysql.c

@@ -693,10 +693,94 @@ run_again:
 
 	/* It may be that the current session has not yet started
 	its transaction, or it has been committed: */
-		
+
+	trx_start_if_not_started(trx);
+
+	err = lock_table(0, prebuilt->table, prebuilt->select_lock_type, thr);
+
+	trx->error_state = err;
+
+	if (err != DB_SUCCESS) {
+		que_thr_stop_for_mysql(thr);
+
+		was_lock_wait = row_mysql_handle_errors(&err, trx, thr, NULL);
+
+		if (was_lock_wait) {
+			goto run_again;
+		}
+
+		trx->op_info = (char *) "";
+
+		return(err);
+	}
+
+	que_thr_stop_for_mysql_no_error(thr, trx);
+
+	trx->op_info = (char *) "";
+
+	return((int) err);
+}
+
+/*************************************************************************
+Unlocks a table lock possibly reserved by trx. */
+
+void		  	
+row_unlock_table_for_mysql(
+/*=======================*/
+	trx_t*	trx)	/* in: transaction */
+{
+	if (!trx->n_tables_locked) {
+
+		return;
+	}
+
+	mutex_enter(&kernel_mutex);
+	lock_release_tables_off_kernel(trx);
+	mutex_exit(&kernel_mutex);
+}
+/*************************************************************************
+Sets a table lock on the table mentioned in prebuilt. */
+
+int
+row_lock_table_for_mysql(
+/*=====================*/
+					/* out: error code or DB_SUCCESS */
+	row_prebuilt_t*	prebuilt)	/* in: prebuilt struct in the MySQL
+					table handle */
+{
+	trx_t*		trx 		= prebuilt->trx;
+	que_thr_t*	thr;
+	ulint		err;
+	ibool		was_lock_wait;
+	
+	ut_ad(trx);
+	ut_ad(trx->mysql_thread_id == os_thread_get_curr_id());
+
+	trx->op_info = (char *) "setting table lock";
+
+	if (prebuilt->sel_graph == NULL) {
+		/* Build a dummy select query graph */
+		row_prebuild_sel_graph(prebuilt);
+	}
+
+	/* We use the select query graph as the dummy graph needed
+	in the lock module call */
+
+	thr = que_fork_get_first_thr(prebuilt->sel_graph);
+
+	que_thr_move_to_run_state_for_mysql(thr, trx);
+
+run_again:
+	thr->run_node = thr;
+	thr->prev_node = thr->common.parent;
+
+	/* It may be that the current session has not yet started
+	its transaction, or it has been committed: */
+
 	trx_start_if_not_started(trx);
 
-	err = lock_table(0, prebuilt->table, LOCK_AUTO_INC, thr);
+	err = lock_table(LOCK_TABLE_EXP, prebuilt->table,
+		prebuilt->select_lock_type, thr);
 
 	trx->error_state = err;
 

innobase/trx/trx0trx.c

@@ -151,6 +151,7 @@ trx_create(
 	trx->n_tickets_to_enter_innodb = 0;
 
 	trx->auto_inc_lock = NULL;
+	trx->n_tables_locked = 0;
 	
 	trx->read_view_heap = mem_heap_create(256);
 	trx->read_view = NULL;
@@ -278,6 +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->dict_operation_lock_mode == 0);
 

mysql-test/r/innodb-lock.result

+drop table if exists t1;
+create table t1 (id integer, x integer) engine=INNODB;
+insert into t1 values(0, 0);
+set autocommit=0;
+SELECT * from t1 where id = 0 FOR UPDATE;
+id	x
+0	0
+set autocommit=0;
+lock table t1 write;
+update t1 set x=1 where id = 0;
+select * from t1;
+id	x
+0	1
+commit;
+update t1 set x=2 where id = 0;
+commit;
+unlock tables;
+select * from t1;
+id	x
+0	2
+commit;
+drop table t1;

mysql-test/r/innodb.result

@@ -431,7 +431,7 @@ Duplicate entry 'test2' for key 2
 select * from t1;
 id	ggid	email	passwd
 1	this will work		
-3	test2		this will work
+4	test2		this will work
 select * from t1 where id=1;
 id	ggid	email	passwd
 1	this will work		

mysql-test/t/innodb-lock.test

+-- source include/have_innodb.inc
+
+connect (con1,localhost,root,,);
+connect (con2,localhost,root,,);
+drop table if exists t1;
+
+#
+# Testing of explicit table locks
+#
+
+connection con1;
+create table t1 (id integer, x integer) engine=INNODB;
+insert into t1 values(0, 0);
+set autocommit=0;
+SELECT * from t1 where id = 0 FOR UPDATE;
+
+connection con2;
+set autocommit=0;
+
+# The following statement should hang because con1 is locking the page
+--send
+lock table t1 write;
+--sleep 2;
+
+connection con1;
+update t1 set x=1 where id = 0;
+select * from t1;
+commit;
+
+connection con2;
+reap;
+update t1 set x=2 where id = 0;
+commit;
+unlock tables;
+
+connection con1;
+select * from t1;
+commit;
+
+drop table t1;

sql/ha_innodb.cc

@@ -4494,12 +4494,11 @@ the SQL statement in case of an error. */
 int
 ha_innobase::external_lock(
 /*=======================*/
-			        /* out: 0 or error code */
+			        /* out: 0 */
 	THD*	thd,		/* in: handle to the user thread */
 	int 	lock_type)	/* in: lock type */
 {
 	row_prebuilt_t* prebuilt = (row_prebuilt_t*) innobase_prebuilt;
-	int 		error = 0;
 	trx_t*		trx;
 
   	DBUG_ENTER("ha_innobase::external_lock");
@@ -4554,11 +4553,21 @@ ha_innobase::external_lock(
 		}
 
 		if (prebuilt->select_lock_type != LOCK_NONE) {
+			if (thd->in_lock_tables) {
+				ulint	error;
+				error = row_lock_table_for_mysql(prebuilt);
+
+				if (error != DB_SUCCESS) {
+					error = convert_error_code_to_mysql(
+						error, user_thd);
+					DBUG_RETURN(error);
+				}
+			}
 
 		  	trx->mysql_n_tables_locked++;
 		}
 
-		DBUG_RETURN(error);
+		DBUG_RETURN(0);
 	}
 
 	/* MySQL is releasing a table lock */
@@ -4566,6 +4575,9 @@ 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 the MySQL lock count drops to zero we know that the current SQL
 	statement has ended */
@@ -4598,7 +4610,7 @@ ha_innobase::external_lock(
 		}
 	}
 
-	DBUG_RETURN(error);
+	DBUG_RETURN(0);
 }
 
 /****************************************************************************