…For 2 or more, the throughput varies a lot from second to second. I draw boxplots, which show…should say that 300 MiB/sec level for random reads and writes is very decent result for SATA card. I …you are interested more in SSD and MySQL questions – I will be giving a webinary “MySQL and SSD” on May-9….
Post: Load management Techniques for MySQL
May 6, 2012 By 3 Comments
…is not MySQL problem, might be even not problem with your MySQL configuration, queries and hardware, even…with multiple level of concurrency and find out doing work from 32 processes is faster …use more than 4 parallel processes heavily writing to database. Introduce Throttling Sometimes even single…
Post: Testing Fusion-io ioDrive
May 3, 2012 By 1 Comment
…It really makes sense to test it under MySQL workload, but before getting to that, let… in the read synchronous case, let me unfold results and show them in timeline (from 0 to …STEC MACH16 Samsung 830 and each card shows individuals patterns and different handling of write and read IO cases. Follow @…
Post: Percona Toolkit 2.1 with New Online Schema Change Tool
April 5, 2012 By 9 Comments
…. Client applications can continue reading and writing the table with no interruption…have completely redesigned and rebuilt the pt-summary and pt-mysql-summary tools…and DEB repositories. And you can read the documentation, discuss it on the mailing list, get the source code from Launchpad, and…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
…Xtrabackup, MyLVMBackup and others use FLUSH TABLES WITH READ LOCK to temporary make MySQL read only…mysql -A in this case, to prevent it from getting field list from all tables) Reads… pending WRITE query blocks any READ queries to execute on the table. mysql> show processlist; …
Post: InnoDB's gap locks
March 27, 2012 By 15 Comments
…write queries, in spite of your chosen transaction isolation level (considering only the two most common isolation levels, REPEATABLE READ and READ…MySQL uses REPEATABLE READ as the default isolation level so it needs to lock the index records and the gaps to avoid phantom reads and…
Comment: INSERT INTO ... SELECT Performance with Innodb tables.
March 7, 2012 By 21 Comments
I am using AWS MySQL RDS, InnoDB engine. Our requirement is to insert data in same table and read from same table. insert into … SAME_TABLE select my_id+1,.,.,.,.,.,.,. from SAME_TABLE where myid = input_my_id (myid is 1st column of composite (5 columns) primary key). Reading and Writing in same…
Comment: InnoDB's gap locks
April 13, 2012 By 15 Comments
… write queries, in spite of your chosen transaction isolation level” I have two sessions with REPEATABLE READ transaction isolation level. mysql>… and session2: session1> start transaction; select * from t; session2> start transaction; select * from t; I delete one row: session2> delete from t…
Post: Testing Samsung SSD SATA 256GB 830 - not all SSD created equal
April 25, 2012 By 10 Comments
… size (to match workload from InnoDB, as this is primary usage for me), and recently I switched … drops that I observe for both random reads and random writes do not allow me to recommend this drive… are interested more in SSD and MySQL questions – I will be giving a webinary “MySQL and SSD” on May-9….
Post: How to diagnose errors in the MySQL error log
March 26, 2012 By 4 Comments
…writing file ‘/tmp/MYK74Kpi’ (Errcode: 28) The gem in all of that mess is this bit: (Errcode: 28). Now, MySQL…MySQL created a temporary table, using the MyISAM storage engine, and… bug — that error comes from the operating system. Typical…of MySQL Troubleshooting by Sveta Smirnova — I have not read …
