I recently mentioned a few of the big “non-starter” limitations Postgres has overcome for specific use cases. I decided to write a series of blog posts on MySQL’s unsolved severe limitations. I mean limitations that really hobble it for major, important needs — not in areas where it isn’t used, but in areas where it [...]
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; |
Percona Server 5.1.47-rel11.0
June 21, 2010 By 13 Comments
Dear Community, Percona Server version 5.1.47-rel11.0 is available for download now. The changes in this release include: New features Percona Server is now based on MySQL 5.1.47, and XtraDB is now based on InnoDB plugin 1.0.8. XtraDB now uses the fast recovery code released in InnoDB Plugin version 1.0.8, instead of Percona’s earlier fast-recovery code. [...]
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 [...]
What to do with MySQL Full Text Search while migrating to Innodb ?
September 10, 2009 By 12 Comments
It is rather typical for systems to start as MyISAM but as system growths to move to Innodb. The reason of the move could be just desire for better data consistency guaranty or being bitten repairing multiple GB MyISAM table few times, though Table Locks is probably the most important issue – with modern multi [...]
How much memory can MySQL use in the worst case?
February 12, 2009 By 17 Comments
I vaguely recall a couple of blog posts recently asking something like “what’s the formula to compute mysqld’s worst-case maximum memory usage?” Various formulas are in wide use, but none of them is fully correct. Here’s why: you can’t write an equation for it.
Living with backups
November 6, 2008 By 28 Comments
Everyone does backups. Usually it’s some nightly batch job that just dumps all MySQL tables into a text file or ordinarily copies the binary files from the data directory to a safe location. Obviously both ways involve much more complex operations than it would seem by my last sentence, but it is not important right [...]
Estimating Undo Space needed for LVM Snapshot
June 9, 2008 By 5 Comments
We know MySQL Backups using LVM are pretty cool (check out mylvmbackup) or MMM though it is quite typical LVM is not configurable properly to be usable for MySQL Backups. Quite frequently I find LVM installed on the system but no free space left to be used as snapshot undo space, which means LVM is [...]
Innodb Performance Optimization Basics
November 1, 2007 By 75 Comments
Interviewing people for our Job Openings I like to ask them a basic question – if you have a server with 16GB of RAM which will be dedicated for MySQL with large Innodb database using typical Web workload what settings you would adjust and interestingly enough most people fail to come up with anything reasonable. [...]
Heikki Tuuri Innodb answers – Part I
October 26, 2007 By 19 Comments
Its almost a month since I promised Heikki Tuuri to answer Innodb Questions. Heikki is a busy man so I got answers to only some of the questions but as people still poking me about this I decided to publish the answers I have so far. Plus we may get some interesting follow up questions [...]
