April 19, 2014

Optimizing InnoDB for creating 30,000 tables (and nothing else)

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, […]

Innodb row size limitation

I recently worked on a customer case where at seemingly random times, inserts would fail with Innodb error 139. This is a rather simple problem, but due to it’s nature, it may only affect you after you already have a system running in production for a while.

Performance problem with Innodb and DROP TABLE

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 […]

Different flavors of InnoDB flushing

In my recent benchmarks, such as this one about the Virident TachIon card, I used different values for innodb_buffer_pool_size, like 13GB, 52GB, and 144GB, for testing the tpcc-mysql database with size 100G. This was needed in order to test different memory/dataset size ratios. But why is it important, and how does it affect how InnoDB works […]

Innodb undo segment size and transaction isolation

You might know if you have long running transactions you’re risking having a lot of “garbage” accumulated in undo segment size which can cause performance degradation as well as increased disk space usage. Long transactions can also be bad for other reasons such as taking row level locks which will prevent other transactions for execution, […]

High Rate insertion with MySQL and Innodb

I again work with the system which needs high insertion rate for data which generally fits in memory. Last time I worked with similar system it used MyISAM and the system was built using multiple tables. Using multiple key caches was the good solution at that time and we could get over 200K of inserts/sec. […]

Spreading .ibd files across multiple disks; the optimization that isn’t

Inspired by Baron’s earlier post, here is one I hear quite frequently – “If you enable innodb_file_per_table, each table is it’s own .ibd file.  You can then relocate the heavy hit tables to a different location and create symlinks to the original location.” There are a few things wrong with this advice:

Percona XtraBackup 1.5-Beta

Percona XtraBackup 1.5-Beta is now available for download. This release adds additional functionality to Percona XtraBackup 1.4, the current general availability version of XtraBackup. This is a beta release. Functionality Added or Changed Support for MySQL 5.5 databases has been implemented. (Yasufumi Kinoshita) XtraBackup can now be built from the MySQL 5.1.52, MySQL 5.5.7, or Percona Server […]

MySQL Partitioning – can save you or kill you

I wanted for a while to write about using MySQL Partitioning for Performance Optimization and I just got a relevant customer case to illustrate it. First you need to understand how partitions work internally. Partitions are on the low level are separate table. This means when you’re doing lookup by partitioned key you will look […]

How well does your table fits in innodb buffer pool ?

Understanding how well your tables and indexes fit to buffer pool are often very helpful to understand why some queries are IO bound and others not – it may be because the tables and indexes they are accessing are not in cache, for example being washed away by other queries. MySQL Server does not provide […]