Bug#11238

"SELECT ... FOR UPDATE executed as consistent read inside LOCK TABLES"
Do not discard lock_type information as handler::start_stmt() may require knowledge.
(fixed by Antony)

mysql-test/r/innodb.result

@@ -2616,31 +2616,50 @@ SET FOREIGN_KEY_CHECKS=1;
 INSERT INTO t2 VALUES(3);
 ERROR 23000: Cannot add or update a child row: a foreign key constraint fails (`test/t2`, CONSTRAINT `c1` FOREIGN KEY (`v`) REFERENCES `t1` (`id`))
 DROP TABLE t2;
-create table test_checksum(a int not null) engine=innodb DEFAULT CHARSET=latin1;
-insert into test_checksum values (1),(2);
+create table t1(a int not null) engine=innodb DEFAULT CHARSET=latin1;
+insert into t1 values (1),(2);
 set autocommit=0;
-checksum table test_checksum;
+checksum table t1;
 Table	Checksum
-test.test_checksum	1531596814
-insert into test_checksum values(3);
-checksum table test_checksum;
+test.t1	1531596814
+insert into t1 values(3);
+checksum table t1;
 Table	Checksum
-test.test_checksum	2605035534
+test.t1	2605035534
 commit;
-checksum table test_checksum;
+checksum table t1;
 Table	Checksum
-test.test_checksum	127268899
+test.t1	127268899
 commit;
-drop table test_checksum;
-create table test_checksum(a int not null) engine=innodb DEFAULT CHARSET=latin1;
-insert into test_checksum values (1),(2);
+drop table t1;
+create table t1(a int not null) engine=innodb DEFAULT CHARSET=latin1;
+insert into t1 values (1),(2);
 set autocommit=1;
-checksum table test_checksum;
+checksum table t1;
 Table	Checksum
-test.test_checksum	1531596814
+test.t1	1531596814
 set autocommit=1;
-insert into test_checksum values(3);
-checksum table test_checksum;
+insert into t1 values(3);
+checksum table t1;
 Table	Checksum
-test.test_checksum	127268899
-drop table test_checksum;
+test.t1	127268899
+drop table t1;
+create table t1 (col1 integer primary key, col2 integer) engine=innodb;
+insert t1 values (1,100);
+create function f1 () returns integer begin
+declare var1 int;
+select col2 into var1 from t1 where col1=1 for update;
+return var1;
+end|
+start transaction;
+select f1();
+f1()
+100
+ update t1 set col2=0 where col1=1;
+select * from t1;
+col1	col2
+1	100
+rollback;
+rollback;
+drop table t1;
+drop function f1;

mysql-test/t/innodb.test

@@ -1571,36 +1571,67 @@ DROP TABLE t2;
 connect (a,localhost,root,,);
 connect (b,localhost,root,,);
 connection a;
-create table test_checksum(a int not null) engine=innodb DEFAULT CHARSET=latin1;
-insert into test_checksum values (1),(2);
+create table t1(a int not null) engine=innodb DEFAULT CHARSET=latin1;
+insert into t1 values (1),(2);
 set autocommit=0;
-checksum table test_checksum;
+checksum table t1;
 connection b;
-insert into test_checksum values(3);
+insert into t1 values(3);
 connection a;
 #
 # Here checksum should not see insert
 #
-checksum table test_checksum;
+checksum table t1;
 connection a;
 commit;
-checksum table test_checksum;
+checksum table t1;
 commit;
-drop table test_checksum;
+drop table t1;
 #
 # autocommit = 1
 #
 connection a;
-create table test_checksum(a int not null) engine=innodb DEFAULT CHARSET=latin1;
-insert into test_checksum values (1),(2);
+create table t1(a int not null) engine=innodb DEFAULT CHARSET=latin1;
+insert into t1 values (1),(2);
 set autocommit=1;
-checksum table test_checksum;
+checksum table t1;
 connection b;
 set autocommit=1;
-insert into test_checksum values(3);
+insert into t1 values(3);
 connection a;
 #
 # Here checksum sees insert
 #
-checksum table test_checksum;
-drop table test_checksum;
+checksum table t1;
+drop table t1;
+
+#
+# BUG#11238 - in prelocking mode SELECT .. FOR UPDATE is changed to
+# non-blocking SELECT
+#
+create table t1 (col1 integer primary key, col2 integer) engine=innodb;
+insert t1 values (1,100);
+delimiter |;
+create function f1 () returns integer begin
+declare var1 int;
+select col2 into var1 from t1 where col1=1 for update;
+return var1;
+end|
+delimiter ;|
+start transaction;
+select f1();
+connection b;
+send update t1 set col2=0 where col1=1;
+connection default;
+select * from t1;
+connection a;
+rollback;
+connection b;
+reap;
+rollback;
+connection default;
+drop table t1;
+drop function f1;
+disconnect a;
+disconnect b;
+

sql/ha_berkeley.cc

@@ -1894,7 +1894,7 @@ int ha_berkeley::external_lock(THD *thd, int lock_type)
   Under LOCK TABLES, each used tables will force a call to start_stmt.
 */
 
-int ha_berkeley::start_stmt(THD *thd)
+int ha_berkeley::start_stmt(THD *thd, thr_lock_type lock_type)
 {
   int error=0;
   DBUG_ENTER("ha_berkeley::start_stmt");

sql/ha_berkeley.h

@@ -124,7 +124,7 @@ class ha_berkeley: public handler
   int extra(enum ha_extra_function operation);
   int reset(void);
   int external_lock(THD *thd, int lock_type);
-  int start_stmt(THD *thd);
+  int start_stmt(THD *thd, thr_lock_type lock_type);
   void position(byte *record);
   int analyze(THD* thd,HA_CHECK_OPT* check_opt);
   int optimize(THD* thd, HA_CHECK_OPT* check_opt);

sql/ha_innodb.cc

@@ -6000,7 +6000,8 @@ int
 ha_innobase::start_stmt(
 /*====================*/
 	              /* out: 0 or error code */
-	THD*    thd)  /* in: handle to the user thread */
+	THD*    thd,  /* in: handle to the user thread */
+        thr_lock_type lock_type)
 {
 	row_prebuilt_t* prebuilt = (row_prebuilt_t*) innobase_prebuilt;
 	trx_t*		trx;
@@ -6041,7 +6042,7 @@ ha_innobase::start_stmt(
 	} else {
 		if (trx->isolation_level != TRX_ISO_SERIALIZABLE
 		    && thd->lex->sql_command == SQLCOM_SELECT
-		    && thd->lex->lock_option == TL_READ) {
+		    && lock_type == TL_READ) {
 	
 			/* For other than temporary tables, we obtain
 			no lock for consistent read (plain SELECT). */

sql/ha_innodb.h

@@ -150,7 +150,7 @@ class ha_innobase: public handler
   	int extra(enum ha_extra_function operation);
   	int external_lock(THD *thd, int lock_type);
 	int transactional_table_lock(THD *thd, int lock_type);
-	int start_stmt(THD *thd);
+        int start_stmt(THD *thd, thr_lock_type lock_type);
 
   	void position(byte *record);
   	ha_rows records_in_range(uint inx, key_range *min_key, key_range

sql/ha_ndbcluster.cc

@@ -3400,7 +3400,7 @@ int ha_ndbcluster::external_lock(THD *thd, int lock_type)
   startTransaction for each transaction/statement.
 */
 
-int ha_ndbcluster::start_stmt(THD *thd)
+int ha_ndbcluster::start_stmt(THD *thd, thr_lock_type lock_type)
 {
   int error=0;
   DBUG_ENTER("start_stmt");

sql/ha_ndbcluster.h

@@ -501,7 +501,7 @@ class ha_ndbcluster: public handler
   int extra(enum ha_extra_function operation);
   int extra_opt(enum ha_extra_function operation, ulong cache_size);
   int external_lock(THD *thd, int lock_type);
-  int start_stmt(THD *thd);
+  int start_stmt(THD *thd, thr_lock_type lock_type);
   const char * table_type() const;
   const char ** bas_ext() const;
   ulong table_flags(void) const;

sql/handler.h

@@ -647,7 +647,7 @@ class handler :public Sql_alloc
   virtual int reset() { return extra(HA_EXTRA_RESET); }
   virtual int external_lock(THD *thd, int lock_type) { return 0; }
   virtual void unlock_row() {}
-  virtual int start_stmt(THD *thd) {return 0;}
+  virtual int start_stmt(THD *thd, thr_lock_type lock_type) {return 0;}
   /*
     This is called to delete all rows in a table
     If the handler don't support this, then this function will

sql/sql_base.cc

@@ -2148,7 +2148,7 @@ static bool check_lock_and_start_stmt(THD *thd, TABLE *table,
     my_error(ER_TABLE_NOT_LOCKED_FOR_WRITE, MYF(0),table->alias);
     DBUG_RETURN(1);
   }
-  if ((error=table->file->start_stmt(thd)))
+  if ((error=table->file->start_stmt(thd, lock_type)))
   {
     table->file->print_error(error,MYF(0));
     DBUG_RETURN(1);