… constantly referring to the amazing MySQL manual, especially the option and variable reference table. But…prealloc_sizeblogpercona.commanual tx_isolationblogpercona.commanual unique_checksblogpercona.commanual updatable_views_with_limitblogpercona.commanual Uptimeblogpercona.commanual Uptime_since_…
Post: MySQL 4 to MySQL 5 Upgrade performance regressions
June 6, 2007 By 8 Comments
… trigger in MySQL 4.0 and large number of transactions in total so serializing them would make MySQL… happens in commit phase which is not counted as “inside innodb”. I wish there would … but dramatically raises number of update transactions per second needed to trigger the problem. Without BBU …
Post: Understanding Multi-node writing conflict metrics in Percona XtraDB Cluster and Galera
November 20, 2012 By 17 Comments
…every node. A ‘local’ certification failure is only counted on the node that was the source of…: instead of a local transaction triggering the failure on commit, this is triggered by Galera replication threads applying…like a bug and is investigating. I’ll update this post if and when an actual bug…
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
…Cache” which is quite helpful for MySQL Performance optimization tasks but there … invalidated from query cache by table updates, this means number of queries …do not need to be cached. Counting query cache efficiency There are …to fragmentation lowmem_prunes can be triggered even if there is some free…
Post: Debugging problems with row based replication
May 6, 2010 By 12 Comments
…format does offer advantages particularly if triggers or stored procedures are used…count(*) from t1; +———-+ | count(*) | +———-+ | 65536 | +———-+ 1 row in set (0.02 sec) My test setup includes a MySQL…340718 Update_rows: table id 15 flags: STMT_END_F ### UPDATE repl.t1 ### …
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By 3 Comments
…, you could potentially trigger crash recovery when… Duplicates: 0 Warnings: 0 mysql> update employees set age = ((YEAR(CURDATE…mysql-bin.000022 | mysql mysql> select count(*) from salaries where emp_no = 10001; +———-+ | count(*) | +———-+ | 0 | +———-+ 1 row in set (0.00 sec) mysql…
Post: Are you designing IO bound or CPU bound application ?
December 20, 2006 By 10 Comments
… look boring and obvious but it is extremely important for MySQL Performance Optimization. In fact I probably have to touch it in every second MySQL Consulting work or even more frequently. IO Bound workload is… will need to add counts for all messages, read messages etc, make sure they are updated (ie use triggers) and make sure all…
Post: Can Innodb Read-Ahead reduce read performance ?
June 26, 2007 By 2 Comments
…state: sleeping Number of rows inserted 60790248, updated 11571576, deleted 0, read 63850963520 0…normal aio reads are in fact counted in pages rather than distinct IO…and so read-ahead is constantly triggered which makes all thread to …was adviseor in this project from MySQL AB side) – to improve how …
Comment: How to calculate a good InnoDB log file size
December 22, 2008 By 38 Comments
mysql> SHOW GLOBAL VARIABLES LIKE ‘innodb_log_file_size’; +———————-+———–+ …. It is one particular transaction that seems to trigger the error and that has a total of … in an ordered update. The total number of rows is 1286113 (determined with SELECT COUNT(*)). The file containing …
