… use sysbench fileio, 16KiB block size (to match workload from InnoDB, as this is primary usage for me), and recently I… IO mode. There are two reasons for that. First, MySQL/InnoDB uses async writes, so this will emulate database load, and… a wild guess about drops – the drive periodically cleans an internal cache or something. To understand better what kind of response…
Post: Testing STEC SSD MACH16 200GB SLC
April 25, 2012 By 7 Comments
… use sysbench fileio, 16KiB block size (to match workload from InnoDB, as this is primary usage for me), and recently I… IO mode. There are two reasons for that. First, MySQL/InnoDB uses async writes, so this will emulate database load, and… to 87 MiB/sec, which I guess is related to internal garbage collector activity. The results for random read case: Very…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
… SESSION_ID: 7234 TABLE_SCHEMA: test TABLE_NAME: my ENGINE: InnoDB NAME: #sql516_1c42_2 TABLE_ROWS: 0 AVG_ROW_…MEMORY ———————- Total memory allocated 132183490560; in additional pool allocated 0 Internal hash tables (constant factor + variable factor) Adaptive hash index …
Post: XtraDB / InnoDB internals in drawing
April 26, 2010 By 4 Comments
I did some drawing exercise and put XtraDB / InnoDB internals in Visio diagram: The XtraDB differences and main parameters are marked out. PDF version is there http://www.percona.com/docs/wiki/percona-xtradb:internals:start.
Post: InnoDB TABLE/INDEX stats
March 20, 2010 By 5 Comments
… INNODB_INDEX_STATS These table show statistics about InnoDB tables ( taken from InnoDB data dictionary). INNODB_TABLE_STATS is | table_name | table name in InnoDB internal…| | modified | internal counter to judge whether statistics recalculation should be done | INNODB_INDEX_STATS is | table_name | table name in InnoDB internal style (‘database…
Post: Fix of InnoDB/XtraDB scalability of rollback segment
January 18, 2009 By 9 Comments
… single and all transactions are serialized accessing to segment. Fortunately InnoDB internally has mechanism to support multiple rollback segments – and Yasufumi just…_commit=2 innodb_log_buffer_size=8M innodb_log_files_in_group=2 innodb_log_file_size=128M innodb_thread_concurrency=0 innodb_extra_rsegments…
Post: Innodb usability and ease of use.
September 28, 2007 By 14 Comments
… are still done similar way ? Other the years variables like innodb_thread_concurrency were added with rather complicated history of changes… or less understandable with value 0 meaning disabling Innodb internal thread queuing. Another one is innodb_flush_logs_at_trx_commit – initially it… and 1. Interesting enough in some cases Innodb team does get things right. innodb_flush_method variable does not use value 0…
Post: How to load large files safely into InnoDB with LOAD DATA INFILE
July 3, 2008 By 28 Comments
… machine from another, which takes about 10 or 12 hours. InnoDB is not optimized for rollbacks, it’s optimized for transactions… load the file in chunks of a million rows each. (InnoDB internally does operations such as ALTER TABLE in 10k row chunks…, col2 bigint(20) default NULL, key(col1), key(col2) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 Here’s the result of loading the…
Post: Heikki Tuuri to answer your in depth Innodb questions
September 28, 2007 By 51 Comments
Have you ever had a question about Innodb internal design or behavior which is not well covered in MySQL … have them answered ! Heikki Tuuri, Creator of Innodb will answer your Questions about Innodb at MySQL Performance Blog. Please leave your questions… Heikki will likely be unable to answer your questions about Innodb new features or timetables.
Post: What is innodb_support_xa?
March 2, 2011 By 3 Comments
… in InnoDB (prepare, then commit). This is necessary not only for user-initiated XA, but also for internal XA coordination between the InnoDB… per commit. The extra fsync is required because during the internal ‘prepare’ stage, the transaction can’t be considered prepared (and… reduce the number of disk flushes and get better InnoDB performance. Having innodb_support_xa enabled on a replication master—or on…
