… select query with ORDER BY, LIMIT and with paging — Handler_read_rnd 12 M Handler_read_rnd_next 4,483 M Created_tmp_disk_tables 5,270 Created_tmp_tables 5,274 Created_tmp_files 37 k Key_reads…
Comment: What does Handler_read_rnd mean?
June 25, 2010 By 15 Comments
Sasha, yes that should do it, and if I understand correctly should even remove the extra EOF call to Handler_read_rnd_next.
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 4 Comments
… 5.6. Next interesting thing are the last two columns of the table above and 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 when…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
….commanual 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…
Comment: MySQL Server Memory Usage
September 1, 2006 By 21 Comments
…5′ ‘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_rollback’, ’4947643…
Comment: What does Handler_read_rnd mean?
June 16, 2010 By 15 Comments
… | | Handler_read_next | 59 | Whereas adding ORDER BY RAND() adds “using temporary; using filesort” to the EXPLAIN, and gives the following: | Handler_read_first | 1 | | Handler_read_next | 59 | | Handler_read_rnd | 59 | | Handler_read_rnd_next | 60 |
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a look at and benchmarking optimizer enhancements one by one. So in the same way this blog post is aimed at a new optimizer enhancement Index Condition …
Comment: How to estimate query completion time in MySQL
June 15, 2010 By 16 Comments
Great tip! Any insight into what the “rnd_next” in “Handler_read_rnd_next” *translates* to? Most status variables are clear to me (e.g. prev/next/key), but this one escapes me.
