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MDEV-530: Cassandra SE: Locking is incorrect

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- Use more permissive locking.
This commit is contained in:
Sergey Petrunya 2012-09-14 09:25:42 +04:00
parent c7b41e5d46
commit c3de7c977a
1 changed files with 31 additions and 4 deletions
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35
storage/cassandra/ha_cassandra.cc
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@ -1420,14 +1420,41 @@ int ha_cassandra::extra(enum ha_extra_function operation)
} }
/* The following function was copied from ha_blackhole::store_lock: */
THR_LOCK_DATA **ha_cassandra::store_lock(THD *thd, THR_LOCK_DATA **ha_cassandra::store_lock(THD *thd,
THR_LOCK_DATA **to, THR_LOCK_DATA **to,
enum thr_lock_type lock_type) enum thr_lock_type lock_type)
{ {
DBUG_ENTER("ha_cassandra::store_lock");
if (lock_type != TL_IGNORE && lock.type == TL_UNLOCK) if (lock_type != TL_IGNORE && lock.type == TL_UNLOCK)
lock.type=lock_type; {
/*
Here is where we get into the guts of a row level lock.
If TL_UNLOCK is set
If we are not doing a LOCK TABLE or DISCARD/IMPORT
TABLESPACE, then allow multiple writers
*/
if ((lock_type >= TL_WRITE_CONCURRENT_INSERT &&
lock_type <= TL_WRITE) && !thd_in_lock_tables(thd)
&& !thd_tablespace_op(thd))
lock_type = TL_WRITE_ALLOW_WRITE;
/*
In queries of type INSERT INTO t1 SELECT ... FROM t2 ...
MySQL would use the lock TL_READ_NO_INSERT on t2, and that
would conflict with TL_WRITE_ALLOW_WRITE, blocking all inserts
to t2. Convert the lock to a normal read lock to allow
concurrent inserts to t2.
*/
if (lock_type == TL_READ_NO_INSERT && !thd_in_lock_tables(thd))
lock_type = TL_READ;
lock.type= lock_type;
}
*to++= &lock; *to++= &lock;
return to; DBUG_RETURN(to);
} }