Commit fa1436bf authored by unknown's avatar unknown
Browse files

BUG#20256 - LOCK WRITE - MyISAM 

Only MyISAM tables locked with LOCK TABLES ... WRITE were affected.

A query that is optimized with index_merge doesn't reflect rows
inserted within LOCK TABLES.

MyISAM doesn't flush a state within LOCK TABLES. index_merge
optimization creates a copy of the handler, which thus gets
outdated MyISAM state.

New handler->clone() method is introduced to fix this problem.
For non-MyISAM storage engines it allocates a handler and opens
it with ha_open(). For MyISAM it additionally copies MyISAM state
pointer to cloned handler.


mysql-test/r/index_merge.result:
  A test case for bug#20256.
mysql-test/t/index_merge.test:
  A test case for bug#20256.
sql/ha_myisam.cc:
  clone method added to handler class.
sql/ha_myisam.h:
  clone method added to handler class.
sql/handler.cc:
  clone method added to handler class.
sql/handler.h:
  clone method added to handler class.
sql/opt_range.cc:
  Use handler clone method.
parent 86ce3096

mysql-test/r/index_merge.result

+31 −0
Original line number Diff line number Diff line
@@ -424,3 +424,34 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	SIMPLE	t3	index_merge	a,b	a,b	5,5	NULL	#	Using intersect(a,b); Using where

drop table t3;

drop table t0, t1, t2;

CREATE TABLE t1(a INT);

INSERT INTO t1 VALUES(1);

CREATE TABLE t2(a INT, b INT, dummy CHAR(16) DEFAULT '', KEY(a), KEY(b));

INSERT INTO t2(a,b) VALUES

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(1,2);

LOCK TABLES t1 WRITE, t2 WRITE;

INSERT INTO t2(a,b) VALUES(1,2);

SELECT t2.a FROM t1,t2 WHERE t2.b=2 AND t2.a=1;

a

1

1

UNLOCK TABLES;

DROP TABLE t1, t2;

mysql-test/t/index_merge.test

+32 −0
Original line number Diff line number Diff line
@@ -383,3 +383,35 @@ explain select * from t3 where a=1 and b=1; 


drop table t3;

drop table t0, t1, t2;



#

# BUG#20256 - LOCK WRITE - MyISAM

#

CREATE TABLE t1(a INT);

INSERT INTO t1 VALUES(1);

CREATE TABLE t2(a INT, b INT, dummy CHAR(16) DEFAULT '', KEY(a), KEY(b));

INSERT INTO t2(a,b) VALUES

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),(0,0),

(1,2);

LOCK TABLES t1 WRITE, t2 WRITE;

INSERT INTO t2(a,b) VALUES(1,2);

SELECT t2.a FROM t1,t2 WHERE t2.b=2 AND t2.a=1;

UNLOCK TABLES;

DROP TABLE t1, t2;

sql/ha_myisam.cc

+8 −0
Original line number Diff line number Diff line
@@ -169,6 +169,14 @@ ha_myisam::ha_myisam(TABLE *table_arg) 
  can_enable_indexes(1)

{}



handler *ha_myisam::clone(MEM_ROOT *mem_root)

{

  ha_myisam *new_handler= static_cast <ha_myisam *>(handler::clone(mem_root));

  if (new_handler)

    new_handler->file->state= file->state;

  return new_handler;

}





static const char *ha_myisam_exts[] = {

  ".MYI",

sql/ha_myisam.h

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ class ha_myisam: public handler 
 public:

  ha_myisam(TABLE *table_arg);

  ~ha_myisam() {}

  handler *clone(MEM_ROOT *mem_root);

  const char *table_type() const { return "MyISAM"; }

  const char *index_type(uint key_number);

  const char **bas_ext() const;

sql/handler.cc

+9 −0
Original line number Diff line number Diff line
@@ -1372,6 +1372,15 @@ int ha_delete_table(THD *thd, enum db_type table_type, const char *path, 
/****************************************************************************

** General handler functions

****************************************************************************/

handler *handler::clone(MEM_ROOT *mem_root)

{

  handler *new_handler= get_new_handler(table, mem_root, table->s->db_type);

  if (new_handler && !new_handler->ha_open(table->s->path, table->db_stat,

                                           HA_OPEN_IGNORE_IF_LOCKED))

    return new_handler;

  return NULL;

}





	/* Open database-handler. Try O_RDONLY if can't open as O_RDWR */

	/* Don't wait for locks if not HA_OPEN_WAIT_IF_LOCKED is set */