… explains more in detail what the “will be disallowed in a future release” means. In MySQL 5.7 the checks will be stricter: in the default SQL mode, a duplicate index will… not redundant ones. What is the difference? Let’s see an example. If we execute: mysql> ALTER TABLE test ADD INDEX (col2); Query OK…
Post: MySQL Query Patterns, Optimized - Webinar questions followup
June 3, 2013 By 2 Comments
… keywords were returned in a different order from what you specify in the query? The tuple comparison you’re referring to is this example… in this case to force MySQL to scan the `title` table first, grouping by kind_id in index order. This made the first table in… Percona Training classes in North America and Europe. Join Percona and the MySQL community at our events. The next one is in London on…
Post: MySQL and the SSB - Part 2 - MyISAM vs InnoDB low concurrency
May 22, 2013 By Leave a Comment
… blog post is part two in what is now a continuing series on the Star Schema Benchmark. In my previous blog post I compared MySQL 5.5.30 to MySQL… adaptive hash index is improving performance of InnoDB significantly during the hot run, as hash indexes are faster than a b-tree index. Also…
Post: Implementing SchemaSpy in your MySQL environment
June 4, 2013 By 2 Comments
…In my case here is the properties file in use for my Percona Server 5.6.10 sandbox: description=MySQL driver=com.mysql… indexes, columns flagged ‘nullable’ and ‘must be unique’ (woops!), single column tables, incrementing column names in… via crontab once you’re done. What are some ERD tools you use …
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
… a bit. Our unit of locking in Innodb is a single row (well, the PRIMARY KEY index entry for that row). This means… has no effect on standard MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL replication? It’s actually much worse than Galera. As I illustrated in a blog…
Post: Galera Flow Control in Percona XtraDB Cluster for MySQL
May 2, 2013 By 5 Comments
…is important to understand. What is flow control? One of the things that people don’t often expect when switching to Galera is existence of a replication feedback mechanism, unlike anything you find in standard async MySQL replication. It is…
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
… Which is the perfect case for read-only transaction optimization in MySQL 5.6, because all SELECT queries in…. No surprises here, the general pattern is consistent with what we saw previously. Note that the… –oltp-read-only=off –oltp-index-updates=0 –oltp-non-index-updates=0 run POINT_SELECT +…
Post: MySQL and Percona Server in LinkBench benchmark
May 8, 2013 By 18 Comments
…is related to BUG#67808. For MySQL 5.6.11 top mutexes is &buf_pool->mutex,&new_index->lock. I profiled 5.6.11 in…In CPU-bounds case MySQL performs quite well, though we can see small performance drop in MySQL 5.6. In IO-bound cases MySQL…
Post: Is your MySQL buffer pool warm? Make it sweat!
April 16, 2013 By 6 Comments
… What does that mean? In most of these high-availability solutions it means that mysqld is …replication. The buffer pool and adaptive hash index on the standby server will not …| percona-playback –mysql-host 127.0.0.1 –mysql-username playback –mysql-password PaSSwOrd –mysql-schema schema_name…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
…60) DEFAULT ” NOT NULL, PRIMARY KEY (id) ) CREATE INDEX k on sbtest$I(k) and tables … is very write intensive. So what are results in this case: InnoDB gradually declines as data growth (which is…_repair_threads = 1 myisam_recover socket=/var/lib/mysql/mysql.sock user=root skip-grant-tables TokuDB-…
