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Displaying posts with tag: database recovery (reset)
Dealing with corrupted InnoDB data

Data corruption! It can happen. Maybe because of a bug or storage problem that you didn’t expect, or MySQL crashes when a page checksum’s result is different from what it expected. Either way, corrupted data can and does occur. What do you do then?

Let’s look at the following example and see what can be done when you face this situation.

We have some valuable data:

> select * from t limit 4;
+---+--------+
| i | c      |
+---+--------+
| 1 | Miguel |
| 2 | Angel  |
| 3 | Miguel |
| 4 | Angel  |
+---+--------+
> select count(*) from t;
+----------+
| count(*) |
+----------+
|  2097152 |
+----------+

One day the query you usually run fails and your application stops working. Even worse, it causes the crash already mentioned:

> select * from t where i=2097151;
ERROR 2006 (HY000): MySQL server has gone away

Usually this is the point when panic starts. The error log …

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Webinar Replay & Slides: Repair & Recovery for Your MySQL, MariaDB & MongoDB / TokuMX Clusters

January 23, 2014 By Severalnines

 

Thanks to everyone who attended this week’s webinar; if you missed the sessions or would like to watch the webinar again and browse through the slides, they are now available online.

 

Special thanks to Seppo Jaakola from Codership, the creators of Galera Cluster, for walking us through the various scenarios of Galera recovery. 

 

Webinar topics discussed: 

  • Redundancy models for Galera, NDB and MongoDB / TokuMX
  • Failover & Recovery (Automatic vs Manual)
  • Zooming into Galera recovery procedures
  • Split brains in multi-datacenter setups

 

Watch the replay:

 

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