Comments on: MySQL is playing funny buggers.

By: David Rubie

David Rubie — Wed, 16 Apr 2008 01:46:45 +0000

Let your mum out of the boot Chris, if she rides up front she will be less inclined to thump.

By: Chris

Chris — Tue, 15 Apr 2008 10:23:23 +0000

The computer people will have heard this one, but for any non-geaks reading this thread who wanted to understand how the experts fix problems (not taking a dig at anybody here)

My mum’s car at the moment has a problem where it sometimes starts making a thumping noise. The only way to fix it is to pull over, turn the car off and then on again. Everything is then fine.

By: Jacques Chester

Jacques Chester — Tue, 15 Apr 2008 04:16:25 +0000

Dave;

That last port is from WP 1.2.

Besides, one word: plugins.

Two more words: Wordpress sucks.

By: Dave Bath

Dave Bath — Tue, 15 Apr 2008 03:39:08 +0000

Just why I prefer to use Oracle or PostgreSQL whenever possible: scalable, good stats/optimizer functions, and reliable:

wordpress-pg.sourceforge.net
codex.wordpress.org/Using_Alternative_Databases

By: swio

swio — Tue, 15 Apr 2008 02:09:30 +0000

The computer people will have heard this one, but for any non-geaks reading this thread who wanted to understand how the experts fix problems (not taking a dig at anybody here)

One day, a Mechanical Engineer, Electrical Engineer, Chemical Engineer and Computer Engineerwere driving down the street in the same car. All of a sudden, the car broke down.

The Mechanical Engineer said, “I think a rod broke.”

The Chemical Engineer said, “The way it sputtered at the end, I don’t think it’s getting gas.”

The Electrical Engineer said, “I think there was a spark and something is wrong with the electrical system.”

All three turned to the computer engineer and said, “What do you think?”

The Computer Engineer said, “I think we should all get out and get back in.”

Or you could just run it on a mainframe ;-)

swio – MF analyst/programmer

By: Jacques Chester

Jacques Chester — Tue, 15 Apr 2008 01:20:06 +0000

I’ve added an index to the id column and at some point I’ll need to dive into the queries to see what other indices are appropriate.

Or I could do a data warehousing thing, dump it off for analysis on my own computer.

By: gilmae

gilmae — Mon, 14 Apr 2008 20:53:25 +0000

meep!

By: Jacques Chester

Jacques Chester — Mon, 14 Apr 2008 13:55:08 +0000

David;

I don’t believe MySQL does that automatically, but I reckon I might run the rebuild and optimise functions now anyway.

Also, I think our on-server stats package might be a problem. It’s got about 850,000 records and not a single index on any column.

By: David Rubie

David Rubie — Mon, 14 Apr 2008 13:10:24 +0000

Is it something silly like a background re-indexing operation? I’m not familiar with MySQL, but other (stupid) databases like Sybase and SQL Server can occasionally act stupid because of the type of scavenging scheme you are running to reclaim resources after (say) a big delete operation. Not all of them show up in the process list either. The other type of issue it might be is a query that is mis-hitting a cached query plan (SQL Server is awful for this) although you usually get 100% utilisation and a query sitting there in the 100% run state without returning anything.

I’d suggest with any big database you want to rebuild the indexes weekly at a quiet time to avoid those kinds of issues.

By: Jacques Chester

Jacques Chester — Mon, 14 Apr 2008 11:46:25 +0000

MySQL itself was jammed up. 100% utilisation of a single CPU, which was suggestive of a single query running at full blast — but no entry in the slow queries log to match.

By: gilmae

gilmae — Mon, 14 Apr 2008 10:44:54 +0000

Which script choked, Jacques?

By: TimT

TimT — Mon, 14 Apr 2008 09:21:31 +0000

Old Jungle saying: never trust MySQL, Myspace, or MY DIERRHAERETIC ARSE.

By: Jacques Chester

Jacques Chester — Mon, 14 Apr 2008 09:12:54 +0000

Clinton;

I do have the slow query log turned on. Nothing in it looks like it should have maxed out the server for five minutes. The worst query in the last day took 6 seconds to do a complex join-and-aggregate over nearly a million records.

By: Clinton Roy

Clinton Roy — Mon, 14 Apr 2008 09:04:40 +0000

Have you turned the slow log on?

log_slow_queries = /var/log/mysql/mysql-slow.log

that let me discover that one of our greylisting databases was terribly slow because it was
using a silly backend for update heavy usage.