…Check for Table Cache Related Allocations There are cases when MySQL will allocate a lot of memory for table…long_data to see whenever sending long data feature is used as it can increase amount of resources prepared statements take…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
…take to complete this statement. Lets look at what the problem is. As of MySQL 5.5 FLUSH TABLES WITH READ LOCK does…check for situation like above and either kill FLUSH TABLES WITH READ LOCK and fail backup or kill long…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…how to build for massive scalability, how to do read-write splitting without breaking the user experience, how to take… what the lead consultant does. We want two sets…customer may call and ask “how long to debug server lockups?” … at, including checking for default users in the mysql.* tables, running…
Post: How much memory Innodb locks really take ?
July 13, 2006 By 11 Comments
…_time: 2006-07-12 07:31:51 Update_time: NULL Check_time: NULL Collation: utf8_general_ci Checksum: NULL Create_options… sec) Table with rather small row size, containing 1638400 rows. Now lets lock all rows in this table and see how long does it take: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select count(i) from…
Post: How to estimate time it takes Innodb to Recover ?
May 9, 2007 By 7 Comments
…batch update for relatively small table) less IO will be… perform same amount of checks if page was already flushed … but again this does not normally take major part of … rolling back uncommitted transactions. As MySQL 5.0 these seems… drives. So how do you estimate how long it takes Innodb to Recover …
Post: Predicting how long data load would take
May 24, 2007 By 12 Comments
… Innodb tables for optimal performance, but effect does not…in a binary form. MySQL Configuration Different storage …CHECKS=0 may be used to speed up load to tables…database data directory to see how much data is loaded… rows were relatively long. In most cases …of data in single table was taking a week …
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 12 Comments
… can easily check that it…take over 40 minutes to execute, because that is how long it takes…tables directly (the tables on which dashboard_customer_sales is built), then the query would take significantly longer (40+ minutes): mysql… version does not take long to refresh: mysql> call flexviews.refresh…
Post: How to load large files safely into InnoDB with LOAD DATA INFILE
July 3, 2008 By 28 Comments
… will take a Very Long Time to do — I hate to think how long….does operations such as ALTER TABLE in 10k row chunks, by the way; I chose 1M because the rows were small). But how…mysql -e “set foreign_key_checks=0; set sql_log_bin=0; set unique_checks=0; load data local infile ‘infile.txt’ into table…
Post: Cache Performance Comparison
August 9, 2006 By 73 Comments
…to check peak performance of all caches compared to MySQL Server, by measuring just the time it takes… how long does it take. Test was done on my home test box (2Ghz AMD Sempron CPU) using MySQL … MySQL queries. On Selecting from the table I should note MySQL is rather fast selecting from the table as…
Post: Beware large Query_Cache sizes
March 23, 2007 By 3 Comments
…MySQL Query Cache being source of serious problems. One would see queries both for MyISAM and Innodb tables…check how long FLUSH QUERY CACHE takes – if it is in seconds this is about as long as invalidation can take in extreme case. How… cache such as memcached which does not have this problem. You …
