… enterprise grade storage. For tests I use sysbench fileio, 16KiB block size (to match workload from InnoDB, as this is primary… asynchronous IO library to get time metrics for particular IO block. so my testing command line looks like: sysbench –test=fileio…=async –file-extra-flags=direct –file-fsync-freq=0 –file-block-size=16384 –report-interval=10 run You may see I…
Post: Testing Samsung SSD SATA 256GB 830 - not all SSD created equal
April 25, 2012 By 10 Comments
… to test it. For tests I use sysbench fileio, 16KiB block size (to match workload from InnoDB, as this is primary… asynchronous IO library to get time metrics for particular IO block. so my testing command line looks like: sysbench –test=fileio…=async –file-extra-flags=direct –file-fsync-freq=0 –file-block-size=16384 –report-interval=10 run You may see I…
Post: Load management Techniques for MySQL
May 6, 2012 By 2 Comments
One of the very frequent cases with performance problems with MySQL is what they happen every so often or certain times. Investigating them we find out what the cause is some batch jobs, reports and other non response time critical activities are overloading the system causing user experience to …
Comment: Make your file system error resilient
April 26, 2012 By 8 Comments
…Number of blocks reserved for root. [...] MySQL server is only one doing writes … be wasted if allocated. When an ext* filesystem with “reserved block count: 0″ is nearly full, this generates file fragmentation, performance…
Comment: InnoDB's gap locks
May 7, 2012 By 14 Comments
… [21,30],but it came out my insert still be blocked. The SHOW ENGINE INNODB STATUS information as follow: —TRANSACTION 0…
Post: Zero-Downtime Schema Changes In MySQL
May 3, 2012 By 2 Comments
… wait instead of a dead lock. No, that would cause blocking that would defeat the purpose of the tool. Q: When…
Comment: How much space does empty Innodb table take ?
April 3, 2012 By 7 Comments
… 16KB block is never completely full. After a lot of churn, the block splits will lead to an average of a block being…, there can be extra copies of a row in the block. * Each field (at least non-NULL fields) has 1 or… free space in the 16KB blocks. And I suspect that, for large tables, completely freed 16KB blocks are not counted as “free…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
… worse as the statement started execution all writes will be blocked to the server, which in the end causes “field list… field list from all tables) Reads though would not be blocked, ie there is no MYISAM like table lock priority problem with pending WRITE query blocks any READ queries to execute on the table. mysql> show…
Comment: Instrumentation and the cost of Foreign Keys
April 19, 2012 By 9 Comments
So, locking and subsequent blocking is one thing, but as you said, the data referenced … data” of the account information will be updated frequently. The blocking issue can be mitigated by keeping it in mind while… with and without FKs to see if the additional locking (blocking aside) has any real concern?
Comment: Best kept MySQLDump Secret
March 30, 2012 By 11 Comments
Eric, I tested it with MySQL 5.5 I think what huarong had is just different timing. ALTER TABLE Will be blocked if that table is being dumped right now. However if mysqldump is processing table “A” and you’re altering table “Z” at this time Alter Table will not be blocked.
