Recently, I have faced one interesting issue with Master(Active)-Master(Passive) replication (RBR + Triggers). Passive master was stopped due to “Duplicate Entry” error with update statement. It was something like this.

Last_Error: Error ‘Duplicate entry ‘29014131’ for key ‘PRIMARY” on query. Default database: ‘db’. Query: ‘UPDATE `db`.`tab1` SET `empid`=’103′, `name`=’Nilnandan’,  `address`=’India ‘, `postcode`=’D100′, `phone`=’878 515 7788’;

Interesting thing was , id (primary key column) was not updated in above update statement. Initially I was confused but when I check further, found that both servers has binglog_format = row and there are some triggers in “tab1” table which is inserting records into “tab2” (Another table).

After some investigation, found that “If under row-based replication the slave applied the triggers as …

Debugging a Production War Story

This is a presentation i made for the 2013 Flipkart BootCampers.

Its a production war story and how we went about debugging the root cause.

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Installing Apache2 With PHP5 And MySQL Support On Fedora 19 (LAMP)

LAMP is short for Linux, Apache, MySQL, PHP. This tutorial shows how you can install an Apache2 webserver on a Fedora 19 server with PHP5 support (mod_php) and MySQL support.

If we have InnoDB pages there are two ways to learn how many records they contain:

• PAGE_N_RECS field in the page header
• Count records while walking over the list of records from infimum to supremum

In some previous revision of the recovery tool a short summary was added to a dump which is produced by the constraints_parser.

But if a page is lost and page_parser hasn’t found it, all records from this page are lost. In other words per-page recovery statistics gives us little idea about whether or not a recovered table is complete.

To cover this flaw a new tool index_check is introduced in …

In part one of this post, I gave you a couple examples of how to backup your MySQL databases using mysqldump. In part two, I will show you how to use the MySQL Enterprise Backup (MEB) to create a full and partial backup.

MySQL Enterprise Backup provides enterprise-grade backup and recovery for MySQL. It delivers hot, online, non-blocking backups on multiple platforms including Linux, Windows, Mac & Solaris. To learn more, you may download a …

Thanks Anna.I was expecting this blog. Your blogs on InnoDB Internals are very good. If possible please write a book on the InnoDB internals.

Regards,
Karthik

I’ll be presenting the keynote for Wednesday’s (31st July) MySQL Virtual Developer Day. The idea behind this event is that you get half a day of on-line presentations as well as live Q&A. My session focuses on what’s new in MySQL – in particular MySQL 5.6 and MySQL Cluster 7.3. As you’ll come to have expected, the event is free but you need to register here.
In the following agenda, all times are local to Singapore…

Percona is glad to announce the release of Percona Monitoring Plugins 1.0.4. The components are designed to integrate seamlessly with widely deployed solutions such as Nagios and Cacti, and are delivered in the form of templates, plugins, and scripts.

Changelog:

* Added Galera/MySQL Monitoring Template for Cacti
* Added “Disk Read/Write Time per IO Request (ms)” graph
* Added “MySQL InnoDB Buffer Pool Efficiency” graph
* Switched ss_get_mysql_stats.php to PHP MySQLi extension and made it working with SSL (bug 1193097)
* Added user info to the max_duration check of pmp-check-mysql-innodb plugin (bug 1185513)
* ss_get_mysql_stats.php default values for ‘$status’ array were null instead of 0 (bug 1070268)
* Introduction of innodb_read_views_memory overrode the InnoDB total memory allocated …

Issue – the OpenStack instances hostnames are not resolved at the moment by their floating IPs.

Fast solution – use PowerDNS
Short story:
1. Boot an instance , assign it a floating IP, open tcp ports 22 8001 and udp port 53.
2. Install PowerDNS, the particular yum package is named pdns.
3. install the mysql backend for PowerDNS, its available as yum package as well.
4. Install MariaDB , set the proper configuration, the initialize it at the default location.
5. Set the pdns user, create the pdns database and create the tables needed.
6. Configure the pdns service to use the gmysql backend.
7. Create and user at the OpenStack MySQL able to connect from the floating IP subnet.
8. Grant that user select permissions on all nova.* tables.
9. At the PowerDNS instance, set simple python / php / bash script to query the nova database and to inject the hostnames and the …