…) from information_schema.tables where engine=’memory’; +——————————-+ | sum(data_length+index_length) | +——————————-+ | 126984 | +——————————-+ 1 row in set (0.98 sec) This… additional pool allocated 0 Internal hash tables (constant factor + variable factor) Adaptive hash index 4422068288 (2039977928 + 2382090360) Page hash 127499384 Dictionary cache 512619219 (509995888…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
…. But InnoDB’s adaptive hash indexes require that the prefix is stored in every record R. An adaptive hash index tries to guess where… can’t wait for ability to create physically sorted indexes with Innodb (with index built by sort) this is when this should… single extent. For big tables, a secondary index reserves different extents from the clustered index. Q4: Does Innodb ever merges sequential pages…
Post: How much memory Innodb Dictionary can take ?
May 6, 2010 By 3 Comments
… set (8.04 sec) mysql> select count(*) from INNODB_SYS_INDEXES; +———-+ | count(*) | +———-+ | 451773 | +———-+ 1 row in set (2.75 sec) In… additional pool allocated 0 Internal hash tables (constant factor + variable factor) Adaptive hash index 17721976 (17701384 + 20592) Page hash 1107208 Dictionary cache 702440032 (4427312…
Post: DROP TABLE and stalls: Lazy Drop Table in Percona Server and the new fixes in MySQL
June 22, 2012 By 33 Comments
… Adaptive Hash Index (AHI) Scan the buffer pool and for each page in the buffer pool If the page has a hash index built… time) and a shared reader-writer lock on the Adaptive Hash Index latch. The buffer pool mutex is a major point of…
Post: Join performance of MyISAM and Innodb
May 29, 2006 By 6 Comments
… done using different kinds of columns – primary key, integer indexed column and indexed char column. The query is also trivial – the point… with index and generally highly optimized Innodb builds hash indexes which helps to speed up lookup by indexes by passing BTREE index and using hash, which…
Comment: How to decrease InnoDB shutdown times
May 14, 2009 By 20 Comments
… ADAPTIVE HASH INDEX” section difference between ‘Inserts’ and ‘merged recs’ will show how many to go. Example : ————————————- INSERT BUFFER AND ADAPTIVE HASH INDEX ————————————- Ibuf: size 4185, free list len 3748, seg size 7934, 65171060 inserts, 65171060 merged recs, 10552858 merges Hash table…
Comment: Heikki Tuuri to answer your in depth Innodb questions
October 3, 2007 By 51 Comments
Question to Heikki Seems that adaptive hash indexes are not used for primary key lookups or not showed … innodb status”. select * from table where id= show innodb status: … Hash table size 10624987, used cells 1, node heap has 1 buffer(s) 0.00 hash searches/s, 15979.01 non-hash searches/s
Post: Can Innodb Read-Ahead reduce read performance ?
June 26, 2007 By 2 Comments
… AND ADAPTIVE HASH INDEX ————————————- Ibuf: size 108931, free list len 64619, seg size 173551, 56290428 inserts, 59538912 merged recs, 3876269 merges Hash table…, node heap has 1974 buffer(s) 867.08 hash searches/s, 532.42 non-hash searches/s — LOG — Log sequence number 586…
Post: Announcing Percona Server 5.5.27-29.0
October 11, 2012 By Leave a Comment
…. Bug fixed #1013644 (Laurynas Biveinis). Multiple adaptive hash index partitions would cause overly large hash index. Fixed by changing the way partition sizes are… crash when compiled with a non-default maximum number of indexes per table. Upstream MySQL bugs: #54127, #61178, #61179 and #61180…
Comment: Index lock and adaptive search - next two biggest InnoDB problems
February 27, 2010 By 12 Comments
Vadim, the adaptive hash index is sometimes even the leading problem on standard non-plugin … inevitably going to become a global problem inside InnoDB. Adaptive hash index is one, but I think the insert buffer, undo logs… engine that has nothing shared? Everything per-table or per-index?
