Posts Categorized: MySQL
I got tired of going all over the place to get information about mysqld variables, so I decided to make a summary of most of them (for version 5.0.27 linux). (Due to lack of horizontal space, I had to make two tables — the second one containing a short description of the variable.) Corrections, additions, and amplifications are welcome. Enjoy!
Pythian will be at the MySQL Conference in Santa Clara, taking in all the material we can, processing it, and spewing out what I hope will be some useful blogs. Watch this space!
Here is the perl script referred to by mysql-memory-usage-profile.
I’m not going to try to post a comprehensive mysql tuning manual here. This post is about taking a snapshot profile of a mysql instance that will allow you to define what type of instance you are dealing with, and give you some idea about whether the current configurations are stable or not.
Those of you who, like we do here at Pythian, have the pleasure of supporting both MySQL and Oracle environments (among others) will definitely know who Tom Kyte is. In any event, reading his blog today I noticed that over the weekend he posted on an error message blurted out of a wordpress environment… something about how the “[MySQL server has gone away]“
Big insider news on James Governor’s blog. They are giving the bigwigs (Gartner, IDC, Forrester et alia) a run for their money in technology analysis. The news is this, MySQL has signed a million euro deal with…..
Just a small thought to share. Oracle doesn’t really comply to the rule 11 of Codd’s 12 rules. It does have database links and tables can be grouped in different locations (databases) but it’s not possible to distribute a table transparently across several locations. MySQL Cluster, on the other hand, distributes rows of a table over different data nodes using hash function on the primary key and it’s transparent to the client so it conforms to the Rule 11 as opposed to Oracle.
Over-the-Top Tales from the Trenches: Bringing order to the chaos of every day DBA life. My aim in any posting is to make your job as a DBA in Oracle, SQLserver and MySQL easier. Ever wondered how to get a quick count of the number of connections per hostname from MySQL? Welcome to the arcane (but extremely powerful) world of the MySQL command line pager.
At the end of my last MySQL post I mentioned strange behavior with GROUP BY and DISTINCT. This MySQL “feature” could save some resources on sorts and aggregates but generally I would avoid it as this is not portable solution. Generally speaking, query output is non-deterministic — it depends on the full table scan implementation and on the physical order of rows in a table. This means that it’s actually a bug and , instead, MySQL should produce and error on those statements.
MySQL – No Index Used With ORDER BY + LIMIT and DISTINCT. This is actually a follow up on my previous post. Developers tried to rewrite all statements and even overdid it. As we say in Russia – “teach fool how to pray and he will break his forehead”.