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Understanding the maximum number of columns in a MySQL table

April 8, 2013 By Stewart Smith 5 Comments

This post was initially going to be two sets of polls: “What is the maximum number of columns in MySQL?” and “What is the minimum maximum number of columns in MySQL?”. Before you read on, ponder those questions and come up with your own answers… and see if you’re right or can prove me wrong! [...]

Filed Under: MySQL Tagged With: columns, CREATE TABLE, ddl, FRM, limits, MySQL, MySQL table, Perl, UNIREG

Percona Live MySQL Conference and Expo 2013: It feels like 2007 again

March 21, 2013 By Vadim Tkachenko Leave a Comment

I actually don’t remember exactly whether it was in 2006, 2007 or 2008 — but around that time the MySQL community had one of the greatest MySQL conferences put on by O’Reilly and MySQL. It was a good, stable, predictable time. Shortly thereafter, the MySQL world saw acquisitions, forks, times of uncertainly, more acquisitions, more forks, [...]

Filed Under: Events and Announcements, MySQL Tagged With: Box, Dimitri Kravtchuk, Esty, facebook, Google, MariaDB, MySQL, MySQL 5.6, NING, nnoDB, O'Reilly, Oracle, Percona Live MySQL Conference and Expo 2013, Percona Server, Percona XtraBackup, Pinterest, Sunny Bains, Tumblr, Twitter, Vadim Tkachenko

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

Is there room for more MySQL IO Optimization?

January 3, 2013 By Peter Zaitsev 11 Comments

I prefer to run MySQL with innodb_flush_method=O_DIRECT in most cases – it makes sure there is no overhead of double buffering and I can save the limited amount of file system cache I would normally have on database server for those things which need to be cached — system files, binary log, FRM files, MySQL [...]

Filed Under: Insight for DBAs, MySQL Tagged With: innodb_flush_method=O_DIRECT, MySQL IO Optimization, Percona Server

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

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

ALTER TABLE: Creating Index by Sort and Buffer Pool Size

June 27, 2012 By Peter Zaitsev 4 Comments

Today I was looking at the ALTER TABLE performance with fast index creation and without it with different buffer pool sizes. Results are pretty interesting. I used modified Sysbench table for these tests because original table as initially created only has index on column K which initially contains only zeros, which means index is very [...]

Filed Under: Insight for DBAs, MySQL

Building Indexes by Sorting In Innodb (AKA Fast Index Creation)

June 19, 2012 By Peter Zaitsev 2 Comments

Innodb can indexes built by sort since Innodb Plugin for MySQL 5.1 which is a lot faster than building them through insertion, especially for tables much larger than memory and large uncorrelated indexes you might be looking at 10x difference or more. Yet for some reason Innodb team has chosen to use very small (just [...]

Filed Under: Benchmarks, Insight for DBAs, MySQL

Data compression in InnoDB for text and blob fields

May 30, 2012 By Michael Coburn 2 Comments

Have you wanted to compress only certain types of columns in a table while leaving other columns uncompressed? While working on a customer case this week I saw an interesting problem where a table had many heavily utilized TEXT fields with some read queries exceeding 500MB (!!), and stored in a 100GB table. In this [...]

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

Troubleshooting MySQL Memory Usage

March 21, 2012 By Peter Zaitsev 5 Comments

One of the most painful troubleshooting tasks with MySQL is troubleshooting memory usage. The problem usually starts like this – you have configured MySQL to use reasonable global buffers, such as innodb_buffer_size, key_buffer_size etc, you have reasonable amount of connections but yet MySQL takes much more memory than you would expect, causing swapping or other [...]

Filed Under: Insight for DBAs, MySQL

Understanding the maximum number of columns in a MySQL table

Percona Live MySQL Conference and Expo 2013: It feels like 2007 again

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

Is there room for more MySQL IO Optimization?

Recovery after DROP & CREATE

MySQL Indexing Best Practices: Webinar Questions Followup

ALTER TABLE: Creating Index by Sort and Buffer Pool Size

Building Indexes by Sorting In Innodb (AKA Fast Index Creation)

Data compression in InnoDB for text and blob fields

Troubleshooting MySQL Memory Usage

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