…to sysbench support for workload against multiple tables ( traditionally it used only single table). It is available from launchpad source tree lp:sysbench . …select insert delete update_index update_non_index to support different OLTP modes. Most interesting: all scripts support –oltp-tables-count=…
Post: Fighting MySQL Replication Lag
September 22, 2008 By 7 Comments
…if you’re using explicit transactions all updates from the transactions are buffered together and when…multiple row insert statement or Fetching data you’re planning to update/delete and having multiple queries to delete… rolex%”; This query will perform full table scan in MySQL 5.0 (even if there are…
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…some tables in MyISAM format in “mysql” database. Plus HEAP/MEMORY tables are used for temporary tables …size – Used by MyISAM tables only to optimize bulk inserts (multiple value inserts). Really helps …/binlogging related options – when to delete binary logs from master. It does not affect …
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
…multiple tables gives some very important benefits – your data > becomes managable, your ALTER TABLE or OPTIMIZE TABLE > now locks small table… in my > Why MySQL Could be slow with Large Tables article. Deciding whether or…, and deletes but there are other benefits. Also – if you’re replicating from a…
Comment: Why MySQL could be slow with large tables ?
January 31, 2008 By 141 Comments
…MySql, Apache and Php. The database has a relatively acceptable size, not only in number of tables, but also in some table…tables are about 10GB in size each (so far, 6 in total). SELECTing data from the tables… ATable(A) ON DELETE NO ACTION …tables). Once again, I use multiple inserts into the table…
Post: Can Innodb Read-Ahead reduce read performance ?
June 26, 2007 By 2 Comments
…59538912 merged recs, 3876269 merges Hash table size 25499819, used cells 1303661…of rows inserted 60790248, updated 11571576, deleted 0, read 63850963520 0.00… poor read-ahead performance plus multiple threads doing scattered O_DIRECT … was adviseor in this project from MySQL AB side) – to improve how…
Post: Using MMM to ALTER huge tables
March 27, 2008 By 11 Comments
…table VALUES (id,value1,value2,..)”; good e.g. “INSERT INTO tables (id,col1,col2,..) VALUES (id,value1,value2,..)”), deletes…multiple pairs doing some changes in parallel and you want to ensure switch from…
Post: MySQL: Followup on UNION for query optimization, Query profiling
August 14, 2006 By 14 Comments
…multiple ages to deal with ether as BETWEEN range or as IN filesort appears and query becomes very slow: mysql> explain select * from…
Post: Efficient Boolean value storage for Innodb Tables
April 23, 2008 By 6 Comments
…storing multiple of boolean values (yes/now or something similar) in the table …table – myisam_data_pointer_size is 6 default plus we need space for delete… use Null-Aware comparison operator: mysql> select count(*) from cbool where c1NULL; +———-+ | count(*) | +———-+ | 1048576 | …
Post: Using VIEW to reduce number of tables used
September 28, 2007 By 12 Comments
…table header modification, which is costly. Of course if you can simply rewrite software to store multiple users per table… view post123 as select id,title,body from post where user_id=123 with check … works for SELECT, UPDATE, DELETE queries but not for INSERT: mysql> insert into post123 values(1,”…
