… avoid deadlocks because InnoDB would lock a gap after the delete in repeatable-read. In RC InnoDB almost never uses a gap locking which is a…
Comment: InnoDB's gap locks
May 7, 2012 By 15 Comments
Hi Miguel ， I’ve tried your example “the affect gap locks to SELECT … FOR UPDATE ” on my server ,and my results … came out my insert still be blocked. The SHOW ENGINE INNODB STATUS information as follow: —TRANSACTION 0 27638, ACTIVE 1207 sec… mysql tables in use 1, locked 1 LOCK WAIT 2 lock struct(s), heap size 1216, 1 row lock(s) MySQL thread id 31929…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
…are not excactly sequential, there is a small gap between each. it is difficult to figure … should be possible to implement online reorganize which locks and reorganizes small portions of table online. Q38… in “show innodb statusâ€. select * from table where id=5 show innodb status: Hash table size…
Comment: InnoDB's gap locks
April 4, 2012 By 15 Comments
…, With READ COMMITTED InnoDB doesn’t take additional locks on the gap, improving the concurrence. You would avoid all “Lock wait timeout exceeded” messages…> commit; session1> select * from t; +——+ | i | +——+ | 21 | | 26 | | 30 | +——+ No locks on the gap, so no wait timeout and more concurrence.
Post: Percona XtraDB Cluster: Multi-node writing and Unexpected deadlocks
August 17, 2012 By 17 Comments
… locking inside of an RDBMS can either be optimistic or pessimistic. Pessimisic locking is what Innodb does as a transaction executes. All the locks… pessimistic locking cluster-wide, it uses optimistic locking. Initially a transaction on PXC behaves much like a regular Innodb transaction. It does pessimistic locking…` of table `test`.`autoinc` trx id 83B lock_mode X locks rec but not gap So far, so good. We have an open…
Post: Percona XtraDB Cluster Feature 2: Multi-Master replication
January 19, 2012 By 22 Comments
… however will increase the response time of the read. This gap between slave and master is the reason why this replication… to two different nodes, the cluster will use an optimistic locking model. That means a transaction will not check on possible… is one of incompatibilities with regular InnoDB, that you may experience. In InnoDB usually DEADLOCK and LOCK TIMEOUT errors happen in response on…
