May 18, 2013

MySQL 5.5 and MySQL 5.6 default variable values differences

February 21, 2013 By 8 Comments

As the part of analyzing surprising MySQL 5.5 vs MySQL 5.6 performance results I’ve been looking at changes to default variable values. To do that I’ve loaded the values from MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query:

Lets go over to see what are the most important changes [...]

Filed Under: Insight for DBAs, MySQL Tagged With: , , ,

A case for MariaDB’s Hash Joins

May 31, 2012 By Leave a Comment

MariaDB 5.3/5.5 has introduced a new join type “Hash Joins” which is an implementation of a Classic Block-based Hash Join Algorithm. In this post we will see what the Hash Join is, how it works and for what types of queries would it be the right choice. I will show the results of executing benchmarks [...]

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: , , , , ,

Data compression in InnoDB for text and blob fields

May 30, 2012 By 2 Comments

Have you wanted to compress only certain types of columns in a table while leaving other columns uncompressed? While working on a customer case this week I saw an interesting problem where a table had many heavily utilized TEXT fields with some read queries exceeding 500MB (!!), and stored in a 100GB table. In this [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL, Percona Software

Performance problem with Innodb and DROP TABLE

February 3, 2011 By 23 Comments

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 [...]

Filed Under: Insight for DBAs, MySQL Tagged With:

Effect from innodb log block size 4096 bytes

January 3, 2011 By 19 Comments

In my post MySQL 5.5.8 and Percona Server: being adaptive I mentioned that I used innodb-log-block-size=4096 in Percona Server to get better throughput, but later Dimitri in his article MySQL Performance: Analyzing Percona’s TPCC-like Workload on MySQL 5.5 sounded doubt that it really makes sense. Here us quote from his article: “Question: what is a [...]

Filed Under: Benchmarks, MySQL Tagged With: ,

MySQL 5.5.8 and Percona Server: being adaptive

December 20, 2010 By 25 Comments

As we can see, MySQL 5.5.8 comes with great improvements and scalability fixes. Adding up all the new features, you have a great release. However, there is one area I want to touch on in this post. At Percona, we consider it important not only to have the best peak performance, but also stable and predictable performance. I refer you [...]

Filed Under: Benchmarks, MySQL Tagged With: , ,

Tuning InnoDB Concurrency Tickets

May 24, 2010 By 5 Comments

InnoDB has an oft-unused parameter innodb_concurrency_tickets that seems widely misunderstood. From the docs: “The number of threads that can enter InnoDB concurrently is determined by the innodb_thread_concurrency variable. A thread is placed in a queue when it tries to enter InnoDB if the number of threads has already reached the concurrency limit. When a thread [...]

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: , , , ,

SSD, XFS, LVM, fsync, write cache, barrier and lost transactions

March 2, 2009 By 32 Comments

We finally managed to get Intel X25-E SSD drive into our lab. I attached it to our Dell PowerEdge R900. The story making it running is worth separate mentioning – along with Intel X25-E I got HighPoint 2300 controller and CentOS 5.2 just could not start with two RAID controllers (Perc/6i and HighPoint 2300). The [...]

Filed Under: Hardware and Storage Tagged With: ,

Linux schedulers in tpcc like benchmark

January 30, 2009 By 19 Comments

I mentioned earlier that IO scheduler CFQ coming by default in RedHat / CentOS 5.x may be not so good for MySQL. And yesterday one customer reported that just changing cfq to noop solved their InnoDB IO problems. I ran tpcc scripts against XtraDB on our Dell PowerEdge R900 server (16 cores, 8 disks in [...]

Filed Under: Benchmarks Tagged With:

Another scalability fix in XtraDB

January 23, 2009 By 13 Comments

Recent scalability fixes in InnoDB and also Google’s and your SMP fixes almost made InnoDB results acceptable in primary key lookups queries, but secondary indexes were forgotten for some time. Now having Dell PowerEdge R900 on board (16CPU cores, 16GB RAM) I have some time for experiments, and I played with queries

Filed Under: Benchmarks, Percona Software Tagged With: ,
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