MySQL’s innodb_file_per_table is a wonderful thing – most of the time. Having every table use its own .ibd file allows you to easily reclaim space when dropping or truncating tables. But in some use cases, it may cause significant performance issues. Many of you in the audience are responsible for running automated tests on your […]
Search Results for: innodb per table
When innodb_file_per_table is OFF and all data is going to be stored in ibdata files. If you drop some tables of delete some data then there is no any other way to reclaim that unused disk space except dump/reload method. When Innodb_file_per_table is ON, each table stores data and indexes in it’s own tablespace file. […]
I’ve been working with an application which does a lot of CREATE and DROP table for Innodb tables and we’ve discovered DROP TABLE can take a lot of time and when it happens a lot of other threads stall in “Opening Tables” State. Also contrary to my initial suspect benchmarking create/drop table was CPU bound […]
One schema optimization we often do is extending index when there are queries which can use more key part. Typically this is safe operation, unless index length increases dramatically queries which can use index can also use prefix of the new index are they ? It turns there are special cases when this is not […]
Everyone using Innodb tables probably got use to the fact Innodb tables perform non locking reads, meaning unless you use some modifiers such as LOCK IN SHARE MODE or FOR UPDATE, SELECT statements will not lock any rows while running. This is generally correct, however there a notable exception – INSERT INTO table1 SELECT * […]
If you use Percona Server 5.5 and you have configured it to use multiple buffer pool instances than sooner or later you’ll see the following lines on the server’s error log and chances are you’ll be worried about them:
InnoDB: detected cycle in LRU for buffer pool 5, skipping to next buffer pool.
InnoDB: detected cycle in LRU for buffer pool 3, skipping to next buffer pool.
InnoDB: detected cycle in LRU for buffer pool 7, skipping to next buffer pool.
Worry not as this is mostly harmless. It’s becoming a February tradition for me (Fernando) […]
A few days ago I wrote about MySQL performance implications of InnoDB isolation modes and I touched briefly upon the bizarre performance regression I found with InnoDB handling a large amount of versions for a single row. Today I wanted to look a bit deeper into the problem, which I also filed as a bug. First […]
Percona is glad to announce the release of Percona XtraBackup 2.2.8 on January 14, 2015. Downloads are available from our download site or Percona Software Repositories. Percona XtraBackup enables MySQL backups without blocking user queries, making it ideal for companies with large data sets and mission-critical applications that cannot tolerate long periods of downtime. Offered […]
Over the past few months I’ve written a couple of posts about dangerous debt of InnoDB Transactional History and about the fact MVCC can be the cause of severe MySQL performance issues. In this post I will cover a related topic – InnoDB Transaction Isolation Modes, their relationship with MVCC (multi-version concurrency control) and how […]
Percona is glad to announce the release of Percona Server 5.6.22-71.0 on January 12, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories. Based on MySQL 5.6.22, including all the bug fixes in it, Percona Server 5.6.22-71.0 is the current GA release in the Percona Server 5.6 series. Percona Server is open-source […]