August 29, 2014

InnoDB scalability issues due to tables without primary keys

Each day there is probably work done to improve performance of the InnoDB storage engine and remove bottlenecks and scalability issues. Hence there was another one I wanted to highlight: Scalability issues due to tables without primary keys This scalability issue is caused by the usage of tables without primary keys. This issue typically shows […]

How to reclaim space in InnoDB when innodb_file_per_table is ON

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. […]

InnoDB performance optimization basics (redux)

I recently stumbled upon a post that Peter Zaitsev published back in 2007 titled “Innodb Performance Optimization Basics.” It’s a great post and reading it inspired me to examine what’s changed in the nearly six years that have followed in terms of MySQL, Percona Server – as well as in all of the other now-available […]

How InnoDB promotes UNIQUE constraints

The other day I was running pt-duplicate-key-checker on behalf of a customer and noticed some peculiar recommendations on an InnoDB table with an odd structure (no PRIMARY key, but multiple UNIQUE constraints). This got me thinking about how InnoDB promotes UNIQUE constraints to the role of PRIMARY KEYs. The documentation is pretty clear: [DOCS] When […]

Introduction to Percona XtraBackup 2.1 (MySQL webinar & more)

Percona XtraBackup 2.1 has been in GA now for a little over four months and has some impressive new features to improve backup performance, security, and storage requirements. When used with Percona Server, additional features are enabled that can provide even more dramatic performance improvements. Percona XtraBackup is open source, free MySQL hot backup software […]

TokuDB vs InnoDB in timeseries INSERT benchmark

This post is a continuation of my research of TokuDB’s  storage engine to understand if it is suitable for timeseries workloads. While inserting LOAD DATA INFILE into an empty table shows great results for TokuDB, what’s more interesting is seeing some realistic workloads. So this time let’s take a look at the INSERT benchmark.

Advanced MySQL Query Tuning: Webinar followup Q&A

Thanks to all who attended my “MySQL Query Tuning” webinar on July 24.  If you missed it, you can you can download the slides and also watch the recorded video. Thank you for the excellent questions after the webinar as well. Query tuning is a big topic and, due to the limited time, I had […]

InnoDB Full-text Search in MySQL 5.6: Part 3, Performance

This is part 3 of a 3 part series covering the new InnoDB full-text search features in MySQL 5.6. To catch up on the previous parts, see part 1 or part 2 Some of you may recall a few months ago that I promised a third part in my InnoDB full-text search (FTS) series, in […]

Checking B+tree leaf nodes list consistency in InnoDB

If we have InnoDB pages there are two ways to learn how many records they contain: PAGE_N_RECS field in the page header Count records while walking over the list of records from infimum to supremum In some previous revision of the recovery tool a short summary was added to a dump which is produced by […]

Recovering temporal types in MySQL 5.6: TIME, TIMESTAMP and DATETIME

MySQL 5.6 introduces a new feature – microseconds resolution in some temporal types. As of 5.6.4 TIME, TIMESTAMP and DATETIME can have a fractional part. To create a field with subseconds you can specify precision in brackets: TIME(3), DATETIME(6) etc. Obviously, the new feature requires the format change. All three types may now have a […]