July 22, 2014

Percona Server 5.5.13-20.4 Stable Release

Percona is glad to announce the release of Percona Server 5.5.13-20.4 on July 1st, 2011 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.5.13, Percona Server Percona Server 5.5.13-20.4 is now the current stable release in the 5.5 series. All of Percona’s software is open-source and free, all the details of the […]

Performance Schema tables stats

My previous benchmark on Performance Schema was mainly in memory workload and against single tables. Now after adding multi-tables support to sysbench, it is interesting to see what statistic we can get from workload that produces some disk IO. So let’s run sysbench against 100 tables, each 5000000 rows (~1.2G ) and buffer pool 30G. […]

Analyzing the distribution of InnoDB log file writes

I recently did a quick analysis of the distribution of writes to InnoDB’s log files. On a high-traffic commodity MySQL server running Percona XtraDB for a gaming workload (mostly inserts to the “moves” table), I used strace to gather statistics about how the log file writes are distributed in terms of write size. InnoDB writes […]

InnoDB TABLE/INDEX stats

In Released and new coming features I did not mentioned two additional INFORMATION_SCHEMA tables available in XtraDB: It is INNODB_TABLE_STATS INNODB_INDEX_STATS These table show statistics about InnoDB tables ( taken from InnoDB data dictionary). INNODB_TABLE_STATS is | table_name | table name in InnoDB internal style (‘database/table’) | | rows | estimated number of all rows […]

InnoDB: look after fragmentation

One problem made me puzzled for couple hours, but it was really interesting to figure out what’s going on. So let me introduce problem at first. The table is

Table has 11864696 rows and takes Data_length: 698,351,616 bytes on disk The problem is that after restoring table from mysqldump, the query that scans data […]

Why InnoDB index cardinality varies strangely

This is a very old draft, from early 2007 in fact. At that time I started to look into something interesting with the index cardinality statistics reported by InnoDB tables. The cardinality varies because it’s derived from estimates, and I know a decent amount about that. The interesting thing I wanted to look into was […]

The perils of InnoDB with Debian and startup scripts

Are you running MySQL on Debian or Ubuntu with InnoDB? You might want to disable /etc/mysql/debian-start. When you run /etc/init.d/mysql start it runs this script, which runs mysqlcheck, which can destroy performance. It can happen on a server with MyISAM tables, if there are enough tables, but it is far worse on InnoDB. There are […]

ANALYZE: MyISAM vs Innodb

Following up on my Previous Post I decided to do little test to see how accurate stats we can get for for Index Stats created by ANALYZE TABLE for MyISAM and Innodb. But before we go into that I wanted to highlight about using ANALYZE TABLE in production as some people seems to be thinking […]

INFORMATION_SCHEMA tables in the InnoDB pluggable storage engine

Much has been written about the new InnoDB pluggable storage engine, which Innobase released at the MySQL conference last month. We’ve written posts ourselves about its fast index creation capabilities and the compressed row format, and how that affects performance. One of the nice things they added in this InnoDB release is INFORMATION_SCHEMA tables that […]

Learning about MySQL Table Fragmentation

Recently I was working with the customer who need quick warmup – to get Innodb table fetched in memory as fast as possible to get good in memory access performance. To do it I run the query: “SELECT count(*) FROM tbl WHERE non_idx_col=0″ I use this particular form of query because it will do full […]