… last year and a bit. We had to recover data using query log, corrupted binary log and dig into MyISAM tables. You… important data is stored on RAID or at least replicated. Alexey also has a task to write more details about Innodb data recovery process and release code for our innodb recovery toolset, so you can recover your data for free if…
Post: Innodb Double Write
August 4, 2006 By 24 Comments
One of very interesting techniques Innodb uses is technique called “doublewrite” It means Innodb will write data twice when it performs table space… needed ? It is needed to archive data safety in case of partial page writes. Innodb does not log full pages to the… know they tend to happen and before Innodb doublewirite was implemented I had couple of data corruptions due to it. So how does…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… performance (keeping data smaller) or can a bit slow it down. Plus there were bunch of micro optimizations in Innodb in 5… switch to Oracle? HT: You are right, bugs that cause data corruption, crashes, or wrong query results get the highest priority. We… not showed up in “show innodb statusâ€. select * from table where id=5 show innodb status: Hash table size 10624987, used…
Post: Innodb Recovery Update - The tricks what failed.
May 24, 2007 By 3 Comments
… had been recovering corrupted Innodb Tablespace and it is finally done now. As this was over than 1TB worth of data we really… some impact. Innodb tables rarely become corrupt Indeed even if you leave out crashes in my experience Innodb tables become corrupted more seldom than MyISAM. Thanks to checksums and crashing in case of corruptions and a lot…
Post: Magic Innodb Recovery self healing
May 22, 2007 By 2 Comments
… dump potentially corrupted tables (in this particular corruption instance Innodb did not print table name in question), drop tables, restart Innodb without innodb_force_recovery… recovery setting as it may allow you to recover more data or avoid full dump and restore. Another trick which helped…
Post: Using MyISAM in production
June 17, 2006 By 36 Comments
… application (storing billions of rows in tens of thousands tables) Innodb was better choice mainly because of thouse other behaviors … well… with MyISAM storage engine. This hidden corruption may later cause crashes wrong query results and further data corruption. Partial updates. MyISAM is does…
Post: Why you can't rely on a replica for disaster recovery
July 31, 2010 By 25 Comments
… ago one of my colleagues and I worked on a data corruption case that reminded me that sometimes people make unsafe assumptions… primary and fallback machine had identically corrupted data files. After running fsck on the replica, the InnoDB data files were entirely deleted. When we arrived on the scene, there was a data directory with an 800+ GB data file…
Post: Recovery beyond data restore
August 2, 2008 By 11 Comments
… all the data back… or sort of. In practice you have to be very careful such as using sync-binlog innodb_flush… only using Innodb tables to be OK in most cases. There are still some edge cases such as modifying meta data stored… have master data lost, such as you have RAID or disk failure. Though it also can be things like Innodb corruption or soft…
Comment: Why you can't rely on a replica for disaster recovery
August 7, 2010 By 25 Comments
Given a properly behaving operating environment, InnoDB does not corrupt your data, and it is better than most at detecting and recovering …/02/08/how-postgresql-protects-against-partial-page-writes-and-data-corruption/.
Post: Announcing Percona Server for MySQL version 5.1.67-14.4
March 8, 2013 By Leave a Comment
…). When option innodb_flush_method=O_DIRECT was set up, log bitmap files were created and treated as InnoDB data files for flushing purposes, which wasn’t original intention. Bug fixed #1105709 (Laurynas Biveinis). INFORMATION_SCHEMA plugin name innodb_changed… result in a heap corruption. Bug fixed #1111226 (Laurynas Biveinis). XtraDB changed page tracking wasn’t compatible with innodb_force_recovery=6…
