I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the Percona documentation or forums. So I present to you what is now my newest Firefox toolbar bookmark: an option and [...]
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 [...]
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 [...]
Impact of the number of idle connections in MySQL
December 17, 2010 By 21 Comments
Be careful with my findings, I appear to have compile in debug mode, I am redoing the benchmarks. Updated version here. I recently had to work with many customers having large number of connections opened in MySQL and although I told them this was not optimal, I had no solid arguments to present. More than [...]
Sharing an auto_increment value across multiple MySQL tables
October 4, 2010 By 9 Comments
The title is SEO bait – you can’t do it. We’ve seen a few recurring patterns trying to achieve similar – and I thought I would share with you my favorite two: Option #1: Use a table to insert into, and grab the insert_id:
1 2 3 4 5 | CREATE TABLE option1 (id int not null primary key auto_increment) engine=innodb; # each insert does one operations to get the value: INSERT INTO option1 VALUES (NULL); # $connection->insert_id(); |
Option #2: Use a table with one just row:
1 2 3 4 5 6 | CREATE TABLE option2 (id int not null primary key) engine=innodb; INSERT INTO option2 VALUES (1); # start from 1 # each insert does two operations to get the value: UPDATE option2 SET id=@id:=id+1; SELECT @id; |
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 [...]
Paul McCullagh answers your questions about PBXT
November 20, 2009 By 2 Comments
Following on from our earlier announcement, Paul McCullagh has responded with the answers to your questions – as well as a few I gathered from other Percona folks, and attendees of OpenSQL Camp. Thank you Paul! What’s the “ideal” use case for the PBXT engine, and how does it compare in performance?  When would I [...]
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 [...]
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 [...]
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
1 | SELECT name FROM sbtest WHERE country_id = ? LIMIT 5 |
