…in current implementation is useless. To get some initial impression about performance …threads with limiting dataset to 3,000,000 rows per table, that is in total… –rand-type=uniform –max-time=1800 –mysql-user=root –report-interval=10 … stats: regular tables: —–cpu—— us sy id wa st 1 0 98 …
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
…rows per second, while retrieval of large rows…MySQL Server complexity it is getting…
Post: The Optimization That (Often) Isn't: Index Merge Intersection
December 14, 2012 By 6 Comments
…MySQL could only use one index per table in a given query … ran it, however, it took 3 seconds. Not only that, … the optimizer just can’t get things right, and you, as …id > 2938575 AND parent_id=0 AND status=1 ORDER BY user_id LIMIT 1\G *************************** 1. row *************************** id…
Post: Edge-case behavior of INSERT...ODKU
October 27, 2012 By 6 Comments
… to 2000 per second, sustained, 24h per day….id | username | host_id | last_modified | +—-+———-+———+———————+ | 1 | foo | 3 | 2012-10-05 22:58:28 | +—-+———-+———+———————+ 1 row… defined first. So, MySQL checks our INSERT,…day, and we get 33.1 days, …
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
… ICE 3.5….get an even distribution, the test data was hashed over the values in the date_id…mysql> show table status like ‘ontime_fact’G *************************** 1. row *************************** Name: ontime_fact Engine: InnoDB Version: 10 Row_format: Compact Rows: 6697533 Avg_row…file-per-table…
Post: When EXPLAIN estimates can go wrong!
October 13, 2011 By 7 Comments
…5.1: mysql [localhost] {msandbox} (foo2) > explain select count(*) from test_estimate where type between 3 and 6 \G *************************** 1. row *************************** id: 1 … of the intermediate pages to get a better estimate of the average number of records per page. If there are less …
Post: Reasons for run-away main Innodb Tablespace
June 10, 2010 By 2 Comments
… cause of getting extremely large …mysql> select * from innodb_rseg; +———+———-+———-+———+————+———–+ | rseg_id | space_id | zip_size…rows. In many cases doing such processes in chunks, updating/deleting may be thousands of rows per…about 3 million of row changes….
Post: Investigating MySQL Replication Latency in Percona XtraDB Cluster
March 3, 2013 By 13 Comments
…id=”attachment_13324″ align=”alignright” width=”300″] Investigating MySQL … reads. My setup is 3 Percona XtraDB Cluster nodes …get fully synchronous replication behavior: mysql> set global wsrep_causal_reads=1; Query OK, 0 rows…on the different cluster node: per-request statistics: min: 0.69ms …
Post: Quickly finding unused indexes (and estimating their size)
December 5, 2012 By 2 Comments
…get…mysql> select * from all_indexes\G … *************************** 33. row *************************** TABLE_SCHEMA: sakila TABLE_NAME: rental INDEX_NAME: rental_date NON_UNIQUE: 0 COLUMN_CNT: 3…per_table, then you can rebuild the tablespace for your table by simply doing: mysql…
Post: Estimating Replication Capacity
July 20, 2010 By 4 Comments
… per customer… mysql> show processlist; +——–+————-+———–+——+———+——+———————————————————————–+——————+ | Id | User | Host …3 rows in set (0.00 sec) 4) Slave Catchup/Binlog Application method. We can just get…
