September 3, 2014

System size and Performance Optimization

Performance optimization is never ending story, you can virtually always find something else to optimize but while on generic system, not tuned by expert you often can get significant performance increase in the matter of hours further performance improvements become more and more time consuming and expensive and gains smaller. This observation does not only […]

Beware: key_buffer_size larger than 4G does not work

I was working with customer today which has MySQL on a system with some 64GB or RAM running MyISAM, so they set key_buffer_size to 16G… and every few days MySQL crashes. Why ? Because key_buffer_size over 4GB in size is not really supported (checked with latest and greatest MySQL Enterprise 5.0.34). It works just fine […]

TMP_TABLE_SIZE and MAX_HEAP_TABLE_SIZE

We all know disk based temporary tables are bad and you should try to have implicit temporary tables created in memory where possible, do to it you should increase tmp_table_size to appropriate value and avoid using blob/text columns which force table creation on the disk because MEMORY storage engine does not support them Right ? […]

Undo area size restriction needed for Innodb

As you can read from my Innodb Architecture and Performance Optimization presentation Innodb automatically manages undo area in system tablespace so you never need to care about it. I present it as positive feature reducing administration effort needed but it also can cause a troubles as it happened for me today: InnoDB: 11 transaction(s) which […]

Choosing proper innodb_log_file_size

If you’re doing significant amount of writes to Innodb tables decent size of innodb_log_file_size is important for MySQL Performance. However setting it too large will increase recovery time, so in case of MySQL crash or power failure it may take long time before MySQL Server is operational again. So how to find the optimal combination […]

InnoDB page size

As maybe you know InnoDB uses hard page size 16Kb for datafiles and for buffer pool. However this size can be changed if you need it for your workload. go to file innobase/include/univ.i, lines:

UNIV_PAGE_SIZE is page size (as you see – default value 16Kb). Possible values for UNIV_PAGE_SIZE is 8K, 16K, 32K, 64K. […]

Reducer.sh – A powerful MySQL test-case simplification/reducer tool

Let me start by saying a big “thank you” to the staff at Oracle for deciding to open source reducer.sh. It’s a tool I developed whilst I was working for them several years ago. Its sole purpose is to do one thing – but do it good: test-case simplification. So, let’s say some customer just […]

Using sysbench 0.5 for performing MySQL benchmarks

Given the recent excitement & interest around OpenStack I wanted to make sure I was ready to conduct appropriate evaluations of system performance.  I generally turn to sysbench since it comes with a variety of different tests (accessed via –test= option interface), including: fileio – File I/O test cpu – CPU performance test memory – […]

Percona XtraDB Cluster 5.6.20-25.7 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on September 1st 2014. Binaries are available from downloads area or from our software repositories. Based on Percona Server 5.6.20-68.0 including all the bug fixes in it, Galera Replicator 3.7, and on Codership wsrep API 25.7, Percona XtraDB Cluster 5.6.20-25.7 is now […]

Galera replication – how to recover a PXC cluster

Galera replication for MySQL brings not only the new, great features to our ecosystem, but also introduces completely new maintenance techniques. Are you concerned about adding such new complexity to your MySQL environment? Perhaps that concern is unnecessarily. I am going to present here some simple tips that hopefully will let fresh Galera users prevent […]