… as Q{FLIGHT_NUMBER}.{QUERY_NUMBER}. In general, each flight examines different time periods or different regions. The flights represent the… MyISAM, Q4.3 examines very little data. It seems that InnoDB performs better when a larger number of rows must be joined together (Q4.1, Q4.2) but worse when small amounts of data are examined. Conclusion In…
Post: Virident vCache vs. FlashCache: Part 2
May 17, 2013 By 3 Comments
… were conducted with approximately 78GiB of data (32 tables, 10M rows each) and a 4GiB buffer pool. The cache devices were… a hypothesis. vCache vs. FlashCache – dirty page threshold Finally, we examine the impact of a couple of different dirty-page ratios…
Comment: Slow Query Log analyzes tools
January 30, 2007 By 84 Comments
… seconds or longer [default: 1] -R=min_rows_examined Include only queries which examined min_rows_examined rows or more -iu=include_user Include only queries… additional statistics: max_query_time, max_rows_examined, execution count [default sorting: max_query_time, max_rows_examined] [multiple] options can be passed more…
Post: Updated msl (microslow) patch, installation walk-through!
April 20, 2008 By 17 Comments
… be logged it must match long_query_time AND min_examined_row_limit AND log_slow_filter. log-slow-queries[=name] Log… SESSION and SET GLOBAL. min_examined_row_limit=# Don’t log queries which examine less than min_examined_row_limit rows to file. If you are not interested in queries which scan no more than N rows…
Post: Debugging problems with row based replication
May 6, 2010 By 12 Comments
… = c1 + 100000 where c1 = 1; Query OK, 1 row affected (0.02 sec) Rows matched: 1 Changed: 1 Warnings: 0 On the… exactly what row is having an issue, we can use the ‘mysqlbinlog’ utility in combination with the slave relay log. Examining the…. mysqlbinlog mysql_sandbox25162-relay-bin.000005 –base64-output=decode-rows -v > decoded.log Examine the decoded binary log with the ‘less’ utility…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
…Id | User | Host | db | Command | Time | State | Info | Rows_sent | Rows_examined | Rows_read | +——-+——+———–+———-+———+——+————————-+—————————–+———–+—————+———–+ | 10219 | root | localhost | dumptest | Query | 324…
Post: Analyzing Slow Query Table in MySQL 5.6
February 18, 2013 By 1 Comment
…(query_time), ‘ Lock_time: ‘, TIME_TO_SEC(lock_time), ‘ Rows_sent: ‘, rows_sent, ‘ Rows_examined: ‘, rows_examined, CHAR(10), ‘SET timestamp=’, UNIX_TIMESTAMP(start_time), ‘;’, CHAR…
Post: How to recover deleted rows from an InnoDB Tablespace
February 20, 2012 By 4 Comments
… from TABLES WHERE TABLE_SCHEMA=’employees’ AND TABLE_NAME=’salaries’; +————+ | ROW_FORMAT | +————+ | Compact | +————+ ~/recovery-tool# ./page_parser -5 -f data/salaries…. This one will connect to the database in order to examine the table and create the table_defs.h content. ~/recovery… the salaries.recovery you can find lot of deleted rows, not only rows deleted accidentally. You should manually find the data you…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… Innodb_row_lock_time_maxblogpercona.commanual Innodb_row_lock_waitsblogpercona.commanual Innodb_rows_deletedblogpercona.commanual Innodb_rows_insertedblogpercona.commanual Innodb_rows_readblogpercona.commanual Innodb_rows_updatedblogpercona…_connectionsblogpercona.commanual max_write_lock_countblogpercona.commanual memlockblogpercona.commanual min_examined_row_limitblogpercona.commanual myisam_block_sizeblogpercona.commanual myisam_data_pointer_sizeblogpercona…
Post: When EXPLAIN can be misleading
November 12, 2006 By 1 Comment
… * from rnd order by r desc limit 1 \G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: rnd type: index possible… badly. Too bad –min-examined-row-limit is not yet implemented 
EXPLAIN would also return misleading number of rows for queries of the…
