Ever ran into a situation where you saw “some important variable you really needed to know about=<optimized out>” while debugging?
Suppose you have turned on innodb_file_per_table (which means that each table has its own tablespace), and you have to drop tables in a background every hour or every day. If its once every day then you can probably schedule the table dropping process to run during off-peak hours. But I have seen cases where the […]
Many people use mysqldump –single-transaction to get consistent backup for their Innodb tables without making database read only. In most cases it works, but did you know there are some cases when you can get table entirely missing from the backup if you use this technique ? The problem comes from the fact how MySQL’s […]
I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the Percona documentation or forums. So I present to you what is now my newest Firefox toolbar bookmark: an option and […]
Following on from our earlier announcement, Paul McCullagh has responded with the answers to your questions – as well as a few I gathered from other Percona folks, and attendees of OpenSQL Camp. Thank you Paul! Whatâ€™s the “ideal” use case for the PBXT engine, and how does it compare in performance? Â When would I […]
It is a known fact that ext3 is not the most efficient file system out there and for example file removals can be painfully slow and cause a lot of random I/O. However, as it turns out, it can sometimes have a much more severe impact on the MySQL performance that it would seem. When […]
I am happy to announce next build of our backup tool. This version contains several bugfixes and introduces initial implementation of incremental backup. Incremental backup works in next way. When you do regular backup, at the end of procedure you can see output:
The latest check point (for incremental): '1319:813219999'
>> log scanned up to (1319 813701532)
Transaction log of lsn (1318 3034677302) to (1319 813701532) was copied.
090404 06:03:29 innobackupex: All tables unlocked
090404 06:03:29 innobackupex: Connection to database server closed
innobackupex: Backup created in directory '/mnt/data/tmp'
innobackupex: MySQL binlog position: filename 'db02-bin.001271', position 247627478
090404 06:07:58 innobackupex: innobackup completed OK!
innobackupex: You must use -i (--ignore-zeros) option for extraction of the tar stream.
which gives start point 1319:813219999 for further incremental backup. This point […]
Sometimes MySQL Replication may run out of sync – because of its own buts or operational limitations or because of application mistake, such as writing to the slave when you should be only writing to the master. In any case you need slave to be synced with Master. To discover the difference between Master and […]
Suppose you want to remove auto_increment from 100G table. No matter if it’s InnoDB or MyISAM, you’d usually ALTER TABLE huge_table CHANGE id id int(6) NOT NULL and then wait hours for table rebuild to complete. If you’re unlucky i.e. you have a lot of indexes and not too much RAM – you could end […]
Its almost a month since I promised Heikki Tuuri to answer Innodb Questions. Heikki is a busy man so I got answers to only some of the questions but as people still poking me about this I decided to publish the answers I have so far. Plus we may get some interesting follow up questions […]