… do something like this in MySQL 5.5, you will succeed without errors or warnings: mysql> ALTER TABLE test ADD INDEX (col2); Query OK… two indexes with the same columns (in the same order) and the server will not complain. If we execute the same sentences in MySQL… 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…
Post: Percona Server 5.1.69-14.7 now available: A drop in replacement for MySQL
June 10, 2013 By 4 Comments
… 2013. A drop in replacement for MySQL, downloads are available here and from the Percona Software Repositories. Based on MySQL 5.1…. Incorrect schema definition for the User Statistics tables in INFORMATION_SCHEMA (CLIENT_STATISTICS, INDEX_STATISTICS, TABLE_STATISTICS, THREAD_STATISTICS, and USER_…
Post: Implementing SchemaSpy in your MySQL environment
June 4, 2013 By 2 Comments
… properties file in use for my Percona Server 5.6.10 sandbox: description=MySQL driver=com.mysql.jdbc.Driver connectionSpec=jdbc:mysql://127.0…names, tables without indexes, columns flagged ‘nullable’ and ‘must be unique’ (woops!), single column tables, incrementing column names in tables, and tables…
Post: MySQL Query Patterns, Optimized - Webinar questions followup
June 3, 2013 By 2 Comments
… columns in a compound index, then the order would matter, and it would have to match the order of columns in the index. Example… index-scan of 7 rows in the `kind_type` table to be first, then look up matching rows in `title` by a secondary index… 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…
Post: MySQL and the SSB - Part 2 - MyISAM vs InnoDB low concurrency
May 22, 2013 By Leave a Comment
… 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 5.6.10, both with… data at the filesystem level. The InnoDB indexes were built using ALTER TABLE fast index creation (merge sort). For the MyISAM tests…
Post: Percona Server 5.6.11-60.3 first Release Candidate now available
June 3, 2013 By 3 Comments
…. Incorrect schema definition for the User Statistics tables in INFORMATION_SCHEMA (CLIENT_STATISTICS, INDEX_STATISTICS, TABLE_STATISTICS, THREAD_STATISTICS, and USER_STATISTICS…. Release notes for Percona Server for MySQL 5.6.11-60.3 are available in our online documentation. Bugs can be reported…
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
… perfect case for read-only transaction optimization in MySQL 5.6, because all SELECT queries in the AUTOCOMMIT mode are, by definition, read… was explained in the original post, but seems to cause much confusion. Even though the read-only transactions optimization in MySQL 5.6…-test-mode=nontrx –oltp-read-only=off –oltp-index-updates=0 –oltp-non-index-updates=0 run POINT_SELECT + UPDATE QPS test…
Post: MySQL and Percona Server in LinkBench benchmark
May 8, 2013 By 18 Comments
…#67808. For MySQL 5.6.11 top mutexes is &buf_pool->mutex,&new_index->lock. I profiled 5.6.11 in this IO… for MySQL 5.6.11. Conclusion: In CPU-bounds case MySQL performs quite well, though we can see small performance drop in MySQL 5.6. In IO-bound cases MySQL still…
Post: Is your MySQL buffer pool warm? Make it sweat!
April 16, 2013 By 6 Comments
… Thursday. I’ll be at the Percona Live MySQL Conference and Expo next week in Santa Clara, California so look for me there – I’d love to connect and talk more about MySQL buffer… traffic except for replication. The buffer pool and adaptive hash index on the standby server will not have recently accessed pages…
Post: Percona Server for MySQL 5.5.30-30.2 now available
April 10, 2013 By 10 Comments
… memory allocators on MySQL performance can be found in this blogpost. (Ignacio Nin) This release of Percona Server for MySQL has fixed a… explicitly named foreign key constraint which implied an implicit secondary index with the same name. Fixed by detecting such cases and… fixed #1015506 (Alexey Bychko). Percona Server for MySQL was missing help texts in the MySQL client because the help tables were missing. Bug…
