… status counters. Counter Name MySQL 5.5 MySQL 5.6 MySQL 5.6 w/ join_buffer_size=6M & read_rnd_buffer_size=6M MariaDB 5… the values for ‘Handler_read_key’, ‘Handler_read_next’ and ‘Handler_read_rnd_next’. MariaDB 5.5 with Hash Joins enabled is doing less Handler reads as compared to…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… bound workload, mentioned above. Counter Name MySQL 5.5 MySQL 5.6 MySQL 5.6 w/ read_rnd_bufer_size=4M MariaDB 5.5 MariaDB… N/A 1 0 Handler_read_key 508833 623738 622184 508913 507516 Handler_read_next 574320 574320 572889 574320 572889 Handler_read_rnd_next 136077 136094 136366 136163 136435 Innodb_buffer_pool_read_ahead 0…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
… in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a… optimizer enhancement Index Condition Pushdown (ICP). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take…
Post: What does Handler_read_rnd mean?
June 15, 2010 By 15 Comments
MySQL‘s SHOW STATUS command has two counters that are often confusing and result in “what does that mean?” questions: Handler_read_rnd Handler_read_rnd_next… was called the handler API, which is why the variables begin with Handler_. Handler_read_rnd counts the number of times the handler::rnd_pos() method is…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL manual, …Handler_prepareblogpercona.commanual Handler_read_firstblogpercona.commanual Handler_read_keyblogpercona.commanual Handler_read_lastblogpercona.commanual Handler_read_nextblogpercona.commanual Handler_read_prevblogpercona.commanual Handler_read_rndblogpercona.commanual Handler_read_rnd…
Post: MySQL: Followup on UNION for query optimization, Query profiling
August 14, 2006 By 12 Comments
…Handler_discover | 0 | | Handler_prepare | 0 | | Handler_read_first | 0 | | Handler_read_key | 1 | | Handler_read_next | 42250 | | Handler_read_prev | 0 | | Handler_read_rnd | 0 | | Handler_read_rnd_next | 0 | | Handler_rollback | 0 | | Handler_savepoint | 0 | | Handler…
Post: How to estimate query completion time in MySQL
April 22, 2008 By 14 Comments
… to choose another thread and watch only its status, but MySQL doesn’t currently let you do that.) The solution was… scan of the fact table. This is shown by the Handler_read_rnd_next status variable. Here’s an easy way to watch… -i 10 | grep Handler_read_rnd_next — ignore the first line of output… | Handler_read_rnd_next | 429224 | So the server was reading roughly 43K rows per…
Comment: What does Handler_read_rnd mean?
June 25, 2010 By 15 Comments
….00 sec) mysql> show status like ‘Handler_read_rnd_next’ ; +———————–+——-+ | Variable_name | Value | +———————–+——-+ | Handler_read_rnd_next | 0 | +———————–+——-+ 1 row in set (0.00 sec) mysql> select * from….00 sec) mysql> show status like ‘Handler_read_rnd_next’ ; +———————–+——-+ | Variable_name | Value | +———————–+——-+ | Handler_read_rnd_next | 4 | +———————–+——-+ 1 row in set (0.00 sec) Handler_read_rnd_next was…
Post: Joining on range? Wrong!
May 17, 2010 By 10 Comments
… beginning of MySQL, however unless …Handler_read%’; +———————–+——–+ | Variable_name | Value | +———————–+——–+ | Handler_read_first | 0 | | Handler_read_key | 3 | | Handler_read_next | 118181 | | Handler_read_prev | 0 | | Handler_read_rnd | 0 | | Handler_read_rnd…
Comment: MySQL Server Memory Usage
September 1, 2006 By 18 Comments
…Handler_commit’, ’19092941′ ‘Handler_delete’, ’0′ ‘Handler_discover’, ’0′ ‘Handler_read_first’, ’1100773′ ‘Handler_read_key’, ’2491307870′ ‘Handler_read_next’, ’1266206297′ ‘Handler_read_prev’, ’0′ ‘Handler_read_rnd‘, ’234159075′ ‘Handler_read_rnd_next’, ’2358572961′ ‘Handler…
