… files on top of a clustered filesystem with an external lock manager. You might say that MySQL/NDB Cluster is also… cluster in AWS, got the volume mounted, and went to try to install MySQL. It failed miserably on the mysql_install…-grant-tables and insert a few rows into an InnoDB table, but trying to run a simple mysqlslap just hung on me…
Post: ZFS on Linux and MySQL
May 24, 2013 By 17 Comments
… test and that’s maybe just normal. We didn’t try too hard to get better performance because we already had… best with InnoDB, with MyISAM you’ll have to start the snapshot while holding a “flush tables with read lock” and the… ray flip a bit on a drive, instead of crashing InnoDB, it will be caught by ZFS and the data will…
Comment: Implications of Metadata Locking Changes in MySQL 5.5
March 27, 2013 By 9 Comments
… InnoDB, then you can further clarify to yourself that the ALTER in your test case is waiting on InnoDB row locks by setting innodb_lock…=3 for update; — session 2 set innodb_lock_wait_timeout=1; alter table t1 engine=innodb; And the alter will timeout after approximately a second with the following error: ERROR 1205 (HY000): Lock wait timeout exceeded; try…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…. Applied to a standalone Innodb instance Let’s break it down a bit. Our unit of locking in Innodb is a single row (well, the PRIMARY KEY index entry for that row). This means typically on a single Innodb…. From other nodes: First to commit wins. The others that try to commit AFTER the first and while the first is…
Post: MySQL and Percona Server in LinkBench benchmark
May 8, 2013 By 18 Comments
… time 5.6.11 spent in LRU_scan. I tried to increase innodb_lru_scan_depth variable to 8k,16k,32k but… loose-innodb_flush_neighbors=0 loose-metadata_locks_hash_instances=256 innodb_buffer_pool_instances=16 # MySQL 5.5 and 5.6 loose-innodb_io_capacity_max = 15000 #Percona only innodb…
Post: MySQL 5.6 Compatible Percona Toolkit 2.2 Released
March 25, 2013 By 2 Comments
…, and its tries and wait time between tries for all operations are configurable. Also, we removed –lock-wait-timeout which set innodb_lock_wait_timeout because that now conflicts, or is at least confused with, lock_wait_timeout…
Post: Innodb Table Locks
July 31, 2012 By 4 Comments
…to happen concurrently. Lets now try same select but add LOCK IN SHARE MODE so it performs locking reads to validate our …locked explicitly Innodb “converts” table lock to “no lock” hence eliminating conflicts on MySQL level table locks for most queries. Summary: MySQL Table level locks and Innodb…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… locks is displayed. OS Wait is not exactly the same as “reservation” – before falling back to complex wait using sync_array Innodb tries… Innodb kernel and still has 400 tickets to use. Innodb tries to limit thread concurrency allowing only innodb_thread_concurrency threads to run inside Innodb…
Post: Choosing innodb_buffer_pool_size
November 3, 2007 By 39 Comments
… may have other settings to play with. Finally you can try locking MySQL in memory by using –memlock – just be careful as… important Innodb algorithms are finely tuned with consideration what is in memory and what is on disk, for example when Innodb tries to avoid holding latches while doing IO while there could be locks set while accessing pages in…
Post: SELECT LOCK IN SHARE MODE and FOR UPDATE
August 6, 2006 By 51 Comments
… ? Not really – for example you could try to update the row which you just locked with SELECT FOR UPDATE but this row… is missing in Innodb locking.? In my oppinion few rather important peices missing in Locking implementation of Innodb are: Lock table Innodb can lock tables but it will still need to set row level locks which is…
