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BUG#20256 - LOCK WRITE - MyISAM

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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outdated MyISAM state.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.
This commit is contained in:
svoj@april.(none)
2006-09-12 18:25:35 +05:00
parent 50192889a4
commit 44f167ee1d
7 changed files with 83 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
mysql-test/r/index_merge.result
View File

@ -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;

32
mysql-test/t/index_merge.test
View File

@ -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;

8
sql/ha_myisam.cc
View File

@ -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",

1
sql/ha_myisam.h
View File

@ -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;

9
sql/handler.cc
View File

@ -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 */

1
sql/handler.h
View File

@ -563,6 +563,7 @@ public:
pushed_cond(NULL)
{}
virtual ~handler(void) { /* TODO: DBUG_ASSERT(inited == NONE); */ }
virtual handler *clone(MEM_ROOT *mem_root);
int ha_open(const char *name, int mode, int test_if_locked);
void adjust_next_insert_id_after_explicit_value(ulonglong nr);
bool update_auto_increment();

5
sql/opt_range.cc
View File

@ -1033,10 +1033,7 @@ int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler)
}
THD *thd= current_thd;
if (!(file= get_new_handler(head, thd->mem_root, head->s->db_type)))
goto failure;
DBUG_PRINT("info", ("Allocated new handler %p", file));
if (file->ha_open(head->s->path, head->db_stat, HA_OPEN_IGNORE_IF_LOCKED))
if (!(file= head->file->clone(thd->mem_root)))
{
/* Caller will free the memory */
goto failure;