1berry/MariaDB-server
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Merge stella.local:/home2/mydev/mysql-5.0-axmrg

Browse Source 
into  stella.local:/home2/mydev/mysql-5.1-axmrg
This commit is contained in:
istruewing@stella.local 2008-03-14 14:15:36 +01:00
commit 857dd49aa8
3 changed files with 85 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
mysql-test/r/query_cache.result
View File

@ -1654,6 +1654,32 @@ set GLOBAL query_cache_type=default;
set GLOBAL query_cache_limit=default;
set GLOBAL query_cache_min_res_unit=default;
set GLOBAL query_cache_size=default;
FLUSH STATUS;
SET GLOBAL query_cache_size=10*1024*1024;
SET @save_concurrent_insert= @@concurrent_insert;
SET GLOBAL concurrent_insert= 0;
CREATE TABLE t1 (c1 INT NOT NULL) ENGINE=MyISAM;
INSERT INTO t1 (c1) VALUES (1), (2);
SHOW GLOBAL VARIABLES LIKE 'concurrent_insert';
Variable_name Value
concurrent_insert 0
SHOW STATUS LIKE 'Qcache_hits';
Variable_name Value
Qcache_hits 0
SELECT * FROM t1;
c1
1
2
SELECT * FROM t1;
c1
1
2
SHOW STATUS LIKE 'Qcache_hits';
Variable_name Value
Qcache_hits 1
DROP TABLE t1;
SET GLOBAL concurrent_insert= @save_concurrent_insert;
SET GLOBAL query_cache_size= default;
End of 5.0 tests
CREATE TABLE t1 (a ENUM('rainbow'));
INSERT INTO t1 VALUES (),(),(),(),();

19
mysql-test/t/query_cache.test
View File

@ -1298,6 +1298,25 @@ set GLOBAL query_cache_limit=default;
set GLOBAL query_cache_min_res_unit=default;
set GLOBAL query_cache_size=default;
#
# Bug#33756 - query cache with concurrent_insert=0 appears broken
#
FLUSH STATUS;
SET GLOBAL query_cache_size=10*1024*1024;
SET @save_concurrent_insert= @@concurrent_insert;
SET GLOBAL concurrent_insert= 0;
CREATE TABLE t1 (c1 INT NOT NULL) ENGINE=MyISAM;
INSERT INTO t1 (c1) VALUES (1), (2);
#
SHOW GLOBAL VARIABLES LIKE 'concurrent_insert';
SHOW STATUS LIKE 'Qcache_hits';
SELECT * FROM t1;
SELECT * FROM t1;
SHOW STATUS LIKE 'Qcache_hits';
DROP TABLE t1;
SET GLOBAL concurrent_insert= @save_concurrent_insert;
SET GLOBAL query_cache_size= default;
--echo End of 5.0 tests
#

70
storage/myisam/ha_myisam.cc
View File

@ -2098,6 +2098,7 @@ my_bool ha_myisam::register_query_cache_table(THD *thd, char *table_name,
*engine_callback,
ulonglong *engine_data)
{
DBUG_ENTER("ha_myisam::register_query_cache_table");
/*
No call back function is needed to determine if a cached statement
is valid or not.
@ -2109,39 +2110,48 @@ my_bool ha_myisam::register_query_cache_table(THD *thd, char *table_name,
*/
*engine_data= 0;
/*
If a concurrent INSERT has happened just before the currently processed
SELECT statement, the total size of the table is unknown.
To determine if the table size is known, the current thread's snap shot of
the table size with the actual table size are compared.
If the table size is unknown the SELECT statement can't be cached.
*/
ulonglong actual_data_file_length;
ulonglong current_data_file_length;
/*
POSIX visibility rules specify that "2. Whatever memory values a
thread can see when it unlocks a mutex <...> can also be seen by any
thread that later locks the same mutex". In this particular case,
concurrent insert thread had modified the data_file_length in
MYISAM_SHARE before it has unlocked (or even locked)
structure_guard_mutex. So, here we're guaranteed to see at least that
value after we've locked the same mutex. We can see a later value
(modified by some other thread) though, but it's ok, as we only want
to know if the variable was changed, the actual new value doesn't matter
*/
actual_data_file_length= file->s->state.state.data_file_length;
current_data_file_length= file->save_state.data_file_length;
if (current_data_file_length != actual_data_file_length)
if (file->s->concurrent_insert)
{
/* Don't cache current statement. */
return FALSE;
/*
If a concurrent INSERT has happened just before the currently
processed SELECT statement, the total size of the table is
unknown.
To determine if the table size is known, the current thread's snap
shot of the table size with the actual table size are compared.
If the table size is unknown the SELECT statement can't be cached.
When concurrent inserts are disabled at table open, mi_open()
does not assign a get_status() function. In this case the local
("current") status is never updated. We would wrongly think that
we cannot cache the statement.
*/
ulonglong actual_data_file_length;
ulonglong current_data_file_length;
/*
POSIX visibility rules specify that "2. Whatever memory values a
thread can see when it unlocks a mutex <...> can also be seen by any
thread that later locks the same mutex". In this particular case,
concurrent insert thread had modified the data_file_length in
MYISAM_SHARE before it has unlocked (or even locked)
structure_guard_mutex. So, here we're guaranteed to see at least that
value after we've locked the same mutex. We can see a later value
(modified by some other thread) though, but it's ok, as we only want
to know if the variable was changed, the actual new value doesn't matter
*/
actual_data_file_length= file->s->state.state.data_file_length;
current_data_file_length= file->save_state.data_file_length;
if (current_data_file_length != actual_data_file_length)
{
/* Don't cache current statement. */
DBUG_RETURN(FALSE);
}
}
/* It is ok to try to cache current statement. */
return TRUE;
DBUG_RETURN(TRUE);
}
#endif