Thanks for all, who attended my webinar, I got many questions and I wanted to take this opportunity to answer them. Q: Even ntp has a delay of 0.3-0.4 between servers does that mean a 0.25 as from logs can be an issue ? A: My demo vms were running for a few hours before [...]
Recovering from a bad UPDATE statement
October 19, 2012 By 5 Comments
Did you just run an UPDATE against your 10 million row users table without a WHERE clause? Did you know that in MySQL 5.5 that sometimes you can recover from a bad UPDATE statement? This is possible if you are running in binlog_format=ROW ! Imagine this scenario:
1 2 3 4 5 6 | CREATE TABLE `t1` ( `c1` int(11) NOT NULL AUTO_INCREMENT, `c2` varchar(10) NOT NULL, PRIMARY KEY (`c1`) ) ENGINE=InnoDB; INSERT INTO `t1` (`c2`) VALUES ('michael'), ('peter'), ('aamina'); |
We run an accidental UPDATE statement that [...]
Distro Packages, Pre-built Binaries or Compile Your Own MySQL
September 4, 2012 By 7 Comments
I’ve been helping customers deploy and maintain MySQL (and variants) for the last couple of years and it has always been interesting to hear customer thoughts on how they want their servers installed. It has also been asked many times not only by our support and consulting customers, but widely from different forums and blogs [...]
Recovery after DROP & CREATE
August 22, 2012 By 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”:
1 2 3 4 5 6 7 8 9 10 11 12 | 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 [...]
MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 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 [...]
Announcing Percona XtraBackup 2.0.1
June 25, 2012 By 1 Comment
Percona is glad to announce the release of Percona XtraBackup 2.0.1 on June 25th, 2012. Downloads are available from our download site and Percona Software Repositories. This release is the current GA (Generally Available) stable release in the 2.0 series. This release contains over 20 fixed bugs, some of the more significant bugs fixed are: [...]
STOP: DELETE IGNORE on Tables with Foreign Keys Can Break Replication
February 2, 2012 By 1 Comment
DELETE IGNORE suppresses errors and downgrades them as warnings, if you are not aware how IGNORE behaves on tables with FOREIGN KEYs, you could be in for a surprise. Let’s take a table with data as example, column c1 on table t2 references column c1 on table t1 – both columns have identical set of rows for [...]
Percona XtraBackup 1.6.4
December 19, 2011 By 9 Comments
Percona is glad to announce the release of Percona XtraBackup 1.6.4 on 19 December, 2011 (Downloads are available here and from the Percona Software Repositories). These release notes are (as always) available from the online Percona XtraBackup documentation. This release is purely composed of bug fixes and is the current stable release of Percona XtraBackup. In this release we now [...]
Statement based replication with Stored Functions, Triggers and Events
December 16, 2011 By 4 Comments
Statement based replication writes the queries that modify data in the Binary Log to replicate them on the slave or to use it as a PITR recovery. Here we will see what is the behavior of the MySQL when it needs to log “not usual” queries like Events, Functions, Stored Procedures, Local Variables, etc. We’ll [...]
Find where your data is replicated, win a Percona Live ticket
October 21, 2011 By Leave a Comment
Percona Live London starts on Monday, so this is the last in the series of free-Percona-Live tickets we’ll give away. But first — have you ever wondered what servers are in your MySQL replication hierarchy? We have, too. As consultants, a lot of times we need to get a quick overview of the whole replication [...]
