Since my first post on MySQL transaction descriptors optimization introduced in Percona Server 5.5.30-30.2 and a followup by Dimitri Kravchuk, we have received a large number of questions on why the benchmark results in both posts look rather different. We were curious as well, so we tried to answer that question by retrying benchmarks on […]
Choosing a good InnoDB log file size is key to InnoDB write performance. This can be done by measuring the amount of writes in the redo logs. You can find a detailed explanation in this post. To sum up, here are the main points: The redo logs should be large enough to store at most […]
As an instructor with Percona I’m sometimes asked about the differences between the READ COMMITTED and REPEATABLE READ transaction isolation levels. There are a few differences between READ-COMMITTED and REPEATABLE-READ, and they are all related to locking.
One of the most important features of InnoDB is the row level locking. This feature provides better concurrency under heavy write load but needs additional precautions to avoid phantom reads and to get a consistent Statement based replication. To accomplish that, row level locking databases also acquire gap locks. What is a Phantom Read A […]
LVM snapshots is one powerful way of taking a consistent backup of your MySQL databases – but did you know that you can now restore directly from a snapshot (and binary logs for point in time recovery) in case of that ‘Oops’ moment? Let me show you quickly how. This howto assumes that you already […]
This is a time-honored topic, and there’s no shortage of articles on the topic on this blog. I wanted to write a post trying to condense and clarify those posts, as it has taken me a while to really understand this relationship. Some basic facts Most of us know that writing into Innodb updates buffer […]
Sometimes we need to restore only some tables from a full backup maybe because your data loss affect a small number of your tables. In this particular scenario is faster to recover single tables than a full backup. This is easy with MyISAM but if your tables are InnoDB the process is a little bit […]
In our recent release of Percona Server 5.5.19 we introduced new value for innodb_flush_neighbor_pages=cont. This way we are trying to deal with the problem of InnoDB flushing.
Once upon a time, it would have been considered madness to even attempt to create 30,000 tables in InnoDB. That time is now a memory. We have customers with a lot more tables than a mere 30,000. There have historically been no tests for anything near this many tables in the MySQL test suite. So, […]
Not everyone may know this, but there are precious few innodb crash recovery tests available. Some folks have noticed this and asked for something to be done about it, but unfortunately, no tests have been created for the main MySQL branch. The MySQL at Facebook branch has a number of tests that are quite interesting. […]