I’ve presented at two different venues about HandlerSocket recently and the number one question that always arises is: Why hasn’t HandlerSocket become more popular than it is? Considering how fast and awesome HandlerSocket is, it’s not seeing as rapid adoption as some might expect. I theorize that there are five reasons for this:
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 [...]
Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
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 [...]
High Rate insertion with MySQL and Innodb
January 7, 2011 By 17 Comments
I again work with the system which needs high insertion rate for data which generally fits in memory. Last time I worked with similar system it used MyISAM and the system was built using multiple tables. Using multiple key caches was the good solution at that time and we could get over 200K of inserts/sec. [...]
Webinar: Introduction to Percona Server, XtraDB and Xtrabackup
November 26, 2010 By 2 Comments
We’ve had such a large number of signups to our Migrating MyISAM to InnoDB webinar, that we decided to hold one more before the year is out: December, 8th 9AM PST: Introduction to Percona Server, XtraDB and Xtrabackup.
Impact of the sort buffer size in MySQL
October 25, 2010 By 8 Comments
The parameter sort_buffer_size is one the MySQL parameters that is far from obvious to adjust. It is a per session buffer that is allocated every time it is needed. The problem with the sort buffer comes from the way Linux allocates memory. Monty Taylor (here) have described the underlying issue in detail, but basically above [...]
How fast is FLUSH TABLES WITH READ LOCK?
April 24, 2010 By 30 Comments
A week or so ago at the MySQL conference, I visited one of the backup vendors in the Expo Hall. I started to chat with them about their MySQL backup product. One of the representatives told me that their backup product uses FLUSH TABLES WITH READ LOCK, which he admitted takes a global lock on [...]
Why you should ignore MySQL’s key cache hit ratio
February 28, 2010 By 28 Comments
I have not caused a fist fight in a while, so it’s time to take off the gloves. I claim that somewhere around of 99% of advice about tuning MySQL’s key cache hit ratio is wrong, even when you hear it from experts. There are two major problems with the key buffer hit ratio, and [...]
How many partitions can you have ?
December 5, 2009 By 19 Comments
I had an interesting case recently. The customer dealing with large MySQL data warehouse had the table which was had data merged into it with INSERT ON DUPLICATE KEY UPDATE statements. The performance was extremely slow. I turned out it is caused by hundreds of daily partitions created for this table. What is the most [...]
More on table_cache
November 26, 2009 By 7 Comments
In my previous post I looked into how large table_cache actually can decrease performance. The “miss” path is getting more expensive very quickly as table cache growths so if you’re going to have high miss ratio anyway you’re better off with small table cache. What I have not checked though is how does table_cache (or [...]
