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Percona XtraDB Cluster 5.5.30-23.7.4 for MySQL now available

April 17, 2013 By Hrvoje Matijakovic 2 Comments

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.30-23.7.4 for MySQL on April 17, 2013. Binaries are available from the downloads area or from our software repositories. New Features: Percona XtraDB Cluster has implemented initial implementation of weighted quorum. Weight for node can be assigned via pc.weight option in the wsrep_provider_options variable. [...]

Filed Under: MySQL, XtraDB Cluster Tagged With: libjemalloc library, pc.weight, Percona XtraDB Cluster

MySQL 5.6.10 Optimizer Limitations: Index Condition Pushdown

March 14, 2013 By Jaime Crespo 2 Comments

While preparing the webinar I will deliver this Friday, I ran into a quite interesting (although not very impacting) optimizer issue: a “SELECT *” taking half the time to execute than the same “SELECT one_indexed_column” query in MySQL 5.6.10. This turned into a really nice exercise for checking the performance and inner workings of one [...]

Filed Under: Events and Announcements, Insight for Developers, MySQL Tagged With: Index Condition Pushdown, Jaime Crespo, MySQL 5.6.10

MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark

March 11, 2013 By Justin Swanhart 7 Comments

So far most of the benchmarks posted about MySQL 5.6 use the sysbench OLTP workload. I wanted to test a set of queries which, unlike sysbench, utilize joins. I also wanted an easily reproducible set of data which is more rich than the simple sysbench table. The Star Schema Benchmark (SSB) seems ideal for this. [...]

Filed Under: MySQL Tagged With: InnoDB plugin, Justin Swanhart, MySQL 5.5, MySQL 5.6, Star Schema Benchmark (SSB), sysbench

InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

March 4, 2013 By Ernie Souhrada 7 Comments

This is part 2 in a 3 part series. In part 1, we took a quick look at some initial configuration of InnoDB full-text search and discovered a little bit of quirky behavior; here, we are going to run some queries and compare the result sets. Our hope is that the one of two things [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: Ernie Souhrada, FTS, FullText Search, InnoDB, MyISAM, MySQL 5.6

InnoDB Full-text Search in MySQL 5.6 (part 1)

February 26, 2013 By Ernie Souhrada 1 Comment

I’ve never been a very big fan of MyISAM; I would argue that in most situations, any possible advantages to using MyISAM are far outweighed by the potential disadvantages and the strengths of InnoDB. However, up until MySQL 5.6, MyISAM was the only storage engine with support for full-text search (FTS). And I’ve encountered many [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: Ernie Souhrada, FTS, FullText Search, InnoDB, MyISAM, MySQL 5.6

The Optimization That (Often) Isn’t: Index Merge Intersection

December 14, 2012 By Ernie Souhrada 6 Comments

Prior to version 5.0, MySQL could only use one index per table in a given query without any exceptions; folks that didn’t understand this limitation would often have tables with lots of single-column indexes on columns which commonly appeared in their WHERE clauses, and they’d wonder why the EXPLAIN plan for a given SELECT would [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL

Recovery after DROP & CREATE

August 22, 2012 By Aleksandr Kuzminsky 1 Comment

In a very popular data loss scenario a table is dropped and empty one is created with the same name. This is because mysqldump in many cases generates the “DROP TABLE” instruction before the “CREATE TABLE”:

DROP TABLE IF EXISTS `actor`;
/*!40101 SET @saved_cs_client     = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `actor` (
  `actor_id` smallint(5) unsigned NOT NULL AUTO_INCREMENT,
  `first_name` varchar(45) NOT NULL,
  `last_name` varchar(45) NOT NULL,
  `last_update` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`actor_id`),
  KEY `idx_actor_last_name` (`last_name`)
) ENGINE=InnoDB AUTO_INCREMENT=201 DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;

DROP TABLE IF EXISTS `actor`;

/*!40101 SET @saved_cs_client = @@character_set_client */;

/*!40101 SET character_set_client = utf8 */;

CREATE TABLE `actor` (

`actor_id` smallint(5) unsigned NOT NULL AUTO_INCREMENT,

`first_name` varchar(45) NOT NULL,

`last_name` varchar(45) NOT NULL,

`last_update` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

PRIMARY KEY (`actor_id`),

KEY `idx_actor_last_name` (`last_name`)

) ENGINE=InnoDB AUTO_INCREMENT=201 DEFAULT CHARSET=utf8;

/*!40101 SET character_set_client = @saved_cs_client */;

If there were no subsequent CREATE TABLE the recovery would be trivial. Index_id of the PRIMARY index of [...]

Filed Under: MySQL Tagged With: drop table, InnoDB, Recovery

Percona XtraDB Cluster: Multi-node writing and Unexpected deadlocks

August 17, 2012 By Jay Janssen 17 Comments

Percona XtraDB Cluster (PXC) and the technology it uses (Galera) is an exciting alternative to traditional MySQL replication. For those who don’t know, it gives you: Fully Synchronous replication with a write latency increase equivalent to a ping RTT to the furthest node Automatic cluster synchronization, both incremental and full restores The ability to read [...]

Filed Under: MySQL, XtraDB Cluster

MySQL Indexing Best Practices: Webinar Questions Followup

August 16, 2012 By Peter Zaitsev 4 Comments

I had a lot of questions on my MySQL Indexing: Best Practices Webinar (both recording and slides are available now) We had lots of questions. I did not have time to answer some and others are better answered in writing anyway. Q: One developer on our team wants to replace longish (25-30) indexed varchars with [...]

Filed Under: Insight for DBAs, MySQL

A case for MariaDB’s Hash Joins

May 31, 2012 By Ovais Tariq Leave a Comment

MariaDB 5.3/5.5 has introduced a new join type “Hash Joins” which is an implementation of a Classic Block-based Hash Join Algorithm. In this post we will see what the Hash Join is, how it works and for what types of queries would it be the right choice. I will show the results of executing benchmarks [...]

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: batched key access, block nested loop, hash join, JOIN Performance, MariaDB, Performance

Percona XtraDB Cluster 5.5.30-23.7.4 for MySQL now available

MySQL 5.6.10 Optimizer Limitations: Index Condition Pushdown

MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark

InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

InnoDB Full-text Search in MySQL 5.6 (part 1)

The Optimization That (Often) Isn’t: Index Merge Intersection

Recovery after DROP & CREATE

Percona XtraDB Cluster: Multi-node writing and Unexpected deadlocks

MySQL Indexing Best Practices: Webinar Questions Followup

A case for MariaDB’s Hash Joins

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