…to give it a little help in…MySQL driver=com.mysql.jdbc.Driver connectionSpec=jdbc:mysql://127.0.0.1:5610/schemaspy driverPath=/usr/share/java/mysql…indexes, columns flagged ‘nullable’ and ‘must be unique’ (woops!), single column tables, incrementing column names in…
Post: How to recover table structure from InnoDB dictionary
April 22, 2013 By 4 Comments
…to find InnoDB pages which belong to the table’s index. Which one? A table can have many secondary indexes, but only in the primary index…how the primary index gets created it will have minimal `ID` among the indexes of the table. mysql> select * from SYS_INDEXES…
Post: Galera Flow Control in Percona XtraDB Cluster for MySQL
May 2, 2013 By 5 Comments
…to allow replication to resume as soon as possible. An example configuration tuning flow control in a master/slave cluster might be: mysql…index smaller in…to the application. How to…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…in Innodb is a single row (well, the PRIMARY KEY index…to get to disk. This has no effect on standard MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL…to do? Retrying automatically, or giving your end user a chance to…
Post: Using UNION to implement loose index scan in MySQL
August 10, 2006 By 15 Comments
…MySQL Will not use indexes in all cases when it is technically possible. For multiple key part indexes MySQL will only be able to…MySQL Optimizer would handle this case right it would not be but in this case we only can give a hand to MySQL…
Post: DROP TABLE and stalls: Lazy Drop Table in Percona Server and the new fixes in MySQL
June 22, 2012 By 33 Comments
… I am going to give a high level picture of how Lazy Drop Table works and how the new DROP Table works in MySQL >= 5.5… DROP Table in MySQL >= 5.5.23 work, I would like to mention quickly, that how drop table in MySQL < 5.5.23 used to work. When… Hash Index (AHI) Scan the buffer pool and for each page in the buffer pool If the page has a hash index built…
Post: Percona Live MySQL Conference and Expo 2013 – News from the Committee – Tutorial Selection Complete
December 3, 2012 By 1 Comment
… to being a MySQL DBA and would be an excellent choice for anyone either just getting started in MySQL…INDEXes — All about Indexing Now for one of my former colleages: Rick James of Yahoo! Inc. Rick is giving… focuses in on how the query optimizer does what it does, why it does it, and how to …
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…using the sorted primary key values. Let me give you a simple example. Suppose you have …in MySQL 5.6 code? As MRR was used in both MySQL 5.6 and MariaDB 5.5. Handler_mrr_rowid_refills counts how…value in the index record to make a lookup in the PK. Both these lookups are performed in a single call to…
Post: Tools and Techniques for Index Design Webinar Questions Followup
October 4, 2012 By 5 Comments
I presented a webinar this week to give an overview of Tools and Techniques for Index Design. Even if you missed the webinar… still relevant to current versions of MySQL. Q: How do the upcoming changes in MySQL 5.6 change the best practices for index design? Fundamentally, index design…
Post: Find unused indexes
June 30, 2012 By Leave a Comment
… ago about how to find duplicate indexes. This time we’ll learn how to find unused indexes to continue …in the server. To generate some load on the database I’m going to use the benchmark software tpcc-mysql…to measure the impact on performance. You won’t need to drop all such indexes but it gives…
