Commit 416a6263 authored by Konstantin Osipov's avatar Konstantin Osipov

Backport of:

----------------------------------------------------------
revno: 2630.4.35
committer: Konstantin Osipov <konstantin@mysql.com>
branch nick: mysql-6.0-3726
timestamp: Wed 2008-06-25 16:44:00 +0400
message:
  Fix a MyISAM-specific bug in the new implementation of
  LOCK TABLES (WL#3726).
  If more than one instance of a MyISAM table are open in the
  same connection, all of them must share the same status_param.
  Otherwise, unlock of a table may lead to lost records.
  See also comments in thr_lock.c.
parent edddfa0e
...@@ -160,6 +160,8 @@ void thr_unlock(THR_LOCK_DATA *data); ...@@ -160,6 +160,8 @@ void thr_unlock(THR_LOCK_DATA *data);
enum enum_thr_lock_result thr_multi_lock(THR_LOCK_DATA **data, enum enum_thr_lock_result thr_multi_lock(THR_LOCK_DATA **data,
uint count, THR_LOCK_OWNER *owner); uint count, THR_LOCK_OWNER *owner);
void thr_multi_unlock(THR_LOCK_DATA **data,uint count); void thr_multi_unlock(THR_LOCK_DATA **data,uint count);
void
thr_lock_merge_status(THR_LOCK_DATA **data, uint count);
void thr_abort_locks(THR_LOCK *lock, my_bool upgrade_lock); void thr_abort_locks(THR_LOCK *lock, my_bool upgrade_lock);
my_bool thr_abort_locks_for_thread(THR_LOCK *lock, my_thread_id thread); my_bool thr_abort_locks_for_thread(THR_LOCK *lock, my_thread_id thread);
void thr_print_locks(void); /* For debugging */ void thr_print_locks(void); /* For debugging */
......
...@@ -244,5 +244,23 @@ a ...@@ -244,5 +244,23 @@ a
unlock tables; unlock tables;
drop table t1, t2; drop table t1, t2;
# #
# Ensure that mi_copy_status is called for two instances
# of the same table when it is reopened after a flush.
#
drop table if exists t1;
drop view if exists v1;
create table t1 (c1 int);
create view v1 as select * from t1;
lock tables t1 write, v1 write;
flush table t1;
insert into t1 values (33);
flush table t1;
select * from t1;
c1
33
unlock tables;
drop table t1;
drop view v1;
#
# End of 6.0 tests. # End of 6.0 tests.
# #
...@@ -291,6 +291,24 @@ select * from t1; ...@@ -291,6 +291,24 @@ select * from t1;
unlock tables; unlock tables;
drop table t1, t2; drop table t1, t2;
--echo #
--echo # Ensure that mi_copy_status is called for two instances
--echo # of the same table when it is reopened after a flush.
--echo #
--disable_warnings
drop table if exists t1;
drop view if exists v1;
--enable_warnings
create table t1 (c1 int);
create view v1 as select * from t1;
lock tables t1 write, v1 write;
flush table t1;
insert into t1 values (33);
flush table t1;
select * from t1;
unlock tables;
drop table t1;
drop view v1;
--echo # --echo #
--echo # End of 6.0 tests. --echo # End of 6.0 tests.
......
...@@ -1026,12 +1026,43 @@ thr_multi_lock(THR_LOCK_DATA **data, uint count, THR_LOCK_OWNER *owner) ...@@ -1026,12 +1026,43 @@ thr_multi_lock(THR_LOCK_DATA **data, uint count, THR_LOCK_OWNER *owner)
(long) pos[0]->lock, pos[0]->type); fflush(stdout); (long) pos[0]->lock, pos[0]->type); fflush(stdout);
#endif #endif
} }
/* thr_lock_merge_status(data, count);
Ensure that all get_locks() have the same status DBUG_RETURN(THR_LOCK_SUCCESS);
If we lock the same table multiple times, we must use the same }
status_param!
*/
/**
Ensure that all locks for a given table have the same
status_param.
This is a MyISAM and possibly Maria specific crutch. MyISAM
engine stores data file length, record count and other table
properties in status_param member of handler. When a table is
locked, connection-local copy is made from a global copy
(myisam_share) by mi_get_status(). When a table is unlocked,
the changed status is transferred back to the global share by
mi_update_status().
One thing MyISAM doesn't do is to ensure that when the same
table is opened twice in a connection all instances share the
same status_param. This is necessary, however: for one, to keep
all instances of a connection "on the same page" with regard to
the current state of the table. For other, unless this is done,
myisam_share will always get updated from the last unlocked
instance (in mi_update_status()), and when this instance was not
the one that was used to update data, records may be lost.
For each table, this function looks up the last lock_data in the
list of acquired locks, and makes sure that all other instances
share status_param with it.
*/
void
thr_lock_merge_status(THR_LOCK_DATA **data, uint count)
{
#if !defined(DONT_USE_RW_LOCKS) #if !defined(DONT_USE_RW_LOCKS)
THR_LOCK_DATA **pos= data;
THR_LOCK_DATA **end= data + count;
if (count > 1) if (count > 1)
{ {
THR_LOCK_DATA *last_lock= end[-1]; THR_LOCK_DATA *last_lock= end[-1];
...@@ -1073,7 +1104,6 @@ thr_multi_lock(THR_LOCK_DATA **data, uint count, THR_LOCK_OWNER *owner) ...@@ -1073,7 +1104,6 @@ thr_multi_lock(THR_LOCK_DATA **data, uint count, THR_LOCK_OWNER *owner)
} while (pos != data); } while (pos != data);
} }
#endif #endif
DBUG_RETURN(THR_LOCK_SUCCESS);
} }
/* free all locks */ /* free all locks */
......
...@@ -687,6 +687,8 @@ MYSQL_LOCK *mysql_lock_merge(MYSQL_LOCK *a,MYSQL_LOCK *b) ...@@ -687,6 +687,8 @@ MYSQL_LOCK *mysql_lock_merge(MYSQL_LOCK *a,MYSQL_LOCK *b)
/* Delete old, not needed locks */ /* Delete old, not needed locks */
my_free((uchar*) a,MYF(0)); my_free((uchar*) a,MYF(0));
my_free((uchar*) b,MYF(0)); my_free((uchar*) b,MYF(0));
thr_lock_merge_status(sql_lock->locks, sql_lock->lock_count);
DBUG_RETURN(sql_lock); DBUG_RETURN(sql_lock);
} }
......
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