August 27, 2014

Recovery after DROP [ TABLE | DATABASE ]

In your recovery practice we often face the problem when data lost by execution DROP TABLE or DROP DATABASE statement. In this case even our InnoDB Data Recovery tool can’t help, as table / directory with files was deleted (if you have innodb-file-per-table). And the same for MyISAM, all .MYD / .MYI / .frm – […]

Improving InnoDB recovery time

Speed of InnoDB recovery is known and quite annoying problem. It was discussed many times, see: http://bugs.mysql.com/bug.php?id=29847 http://dammit.lt/2008/10/26/innodb-crash-recovery/ This is problem when your InnoDB crashes, it may takes long time to start. Also it affects restoring from backup (both LVM and xtrabackup / innobackup) In this is simple test, I do crash mysql during in-memory […]

Friday challenge: ibd recovery

I want to make this Friday a bit more interesting – how do you feel to train a bit in InnoDB data recovery techniques. I have .ibd datafile which was created by query CREATE TABLE `tryme` ( `email` mediumblob, `content` mediumblob ) ENGINE=InnoDB … (SOME PARAMETERS SKIPPED) …; and I inserted one record into this […]

Adjusting Innodb for Memory resident workload

As larger and larger amount of memory become common (512GB is something you can fit into relatively commodity server this day) many customers select to build their application so all or most of their database (frequently Innodb) fits into memory. If all tables fit in Innodb buffer pool the performance for reads will be quite […]

How to calculate a good InnoDB log file size

Peter wrote a post a while ago about choosing a good InnoDB log file size.  Not to pick on Peter, but the post actually kind of talks about a lot of things and then doesn’t tell you how to choose a good log file size!  So I thought I’d clarify it a little. The basic […]

Thoughs on Innodb Incremental Backups

For normal Innodb “hot” backups we use LVM or other snapshot based technologies with pretty good success. However having incremental backups remain the problem. First why do you need incremental backups at all ? Why not just take the full backups daily. The answer is space – if you want to keep several generations to […]

Data Recovery Toolkit for InnoDB Version 0.1 Released

As Peter mentioned in one of previous posts, we’ve done huge work developing robust strategies of InnoDB data recovery to provide our customers effective data recovery services and one of major parts of these strategies is our toolkit for InnoDB data recovery. Today I’m proud to announce its first public release which was used to […]

Innodb Second Start prevention bug ?

I filed the following bug today. Basically it looks like in certain conditions Innodb may be started twice in the parallel on the same data files which can hurt database badly. It is true it does not seems to be 100% repeatable but I’ve seen it multiple times in different environments. I’m not sure if […]

How to estimate time it takes Innodb to Recover ?

Today seems to be Innodb day in our Blog, but well this is the question which pops ups quite frequently in Innodb talks and during consulting engagements. It is well known to get better performance you should normally set innodb_log_file_size large. We however usually recommend caution as it may significantly increase recovery time if Innodb […]

MySQL Users Conference – Innodb

It might look like it is too late to write about stuff happened at Users Conference but I’m just starting find bits of time from processing accumulated backlog. The Theme of this Users Conference was surely Storage Engines both looking at number of third party storage engine presented, main marketing message – Storage Engine partnership […]