rcs1000

Alas: I have no plug-ins enabled, and I have deleted everything in cache. But to no avail. It still says “0 Comments” or “No Comments”.

Just for the record: this query is from is my “recent comments” plug-in. Is it an appalling piece of SQL that’s causing the problem, or could there be something else?

(Essentially, mySQL seems to lock-up… then too many queries… then *poof!* the system is down)

OK: I seem to have narrowed the problem down to mySQL, and in particular to a slow query. This seems to be the issue:

Copying to tmp table | SELECT * FROM wp_comments WHERE (comment_approved=’1′) GROUP BY Comment_ID DESC LIMIT 5

Which is often taking a long, long time because the table – presumably – is locked. Does anyone have any idea why this might happen, and how it can be stopped?

Grrr… thanks, Robert

Well, I’ve turned off KeepAlive. I don’t know whether that will help. I guess I’ll watch and look. MaxClients has been adjusted down to 256. Hopefully, without the KeepAlive… well, we’ll see.

Gosh – this is all turning into a horrible admin nightmare. I’ve also been getting “too many connections” errors on mysql – perhaps due to me restarting apache repeatedly, or perhaps the source of the problem.

And my logs are multi-gigabyte size… I really wish I knew what i was doing!

OK. Only thing in the error log that looks like a likely culprit is:

“server reached MaxClients setting, consider raising the MaxClients setting”, that occurs just before the site goes into slow-mo!

I’ve upped it to 500 – but to be honest, I don’t think that’s the real problem. “ps -All” shows about 100 apache2 processes… and I suspect it’ll now race up to 500. Maybe it’s not timing out connections fast enough? But why would that only occur now?

Hmmmm….

Woah! Whole system now unstable. Power cycle time…

(I will check the error logs when it comes back up.)

OK – I tried that, and again have come up against the same problem. After a while the site slows right down (and, indeed, seems now to have stopped completely). When I ssh into the box, it runs at a fair speed, so I’m sure the machine isn’t itself running slow.

I wonder if it’s a slow or malformed SQL query… (damn I wish I could see *where* exactly the system is hiccuping).

Since I posted this, the site has suddenly returned to full performance! Bizarre?

<IfModule prefork.c>
StartServers 5
MinSpareServers 5
MaxSpareServers 10
MaxClients 20
MaxRequestsPerChild 0
</IfModule>

and in mods-enabled are…

cgi.load
mod_python.load
perl.conf
perl.load
php4.conf
php4.load
rewrite.load
userdir.conf
userdir.load

Many thanks,
Robert

Tg,
I’ll dig out my code this evening and email it to you.
Cheers,
Robert

The plug-in can be downloaded here (I wasn’t feeling particularly smart last night, I had a nightmare system administration problem, that turned out to simply be due to someone else on another VM taking all the CPU time…):
https://amoral.org/latest_comments.php.txt
Thanks
Robert

Oh yes; and it can be seen in action – again – at https://testbed.amoral.org

OK Podz,
Details: latest_comments.php is now a plug-in. The plug-in contains a function taking two variables: the number of comments you wish to display and the amount of each comment you wish to show.
The function is simple: it runs a query on the wp_comments table, pulls out the data, and formats it. About 40 lines of code. Nothing spectacularly difficult, but I like the effect.
Regards,
Robert

I have a database backed random quote generator on my web-page https://amoral.org, I haven’t made it into a plug-in but it wouldn’t be particularly hard.
Unfortunately, I’m dealing with a terribly messed up WordPress install right now (my fault, no excuses), and also plu-in-ising my comments hack. So it may take a little while.
Watch this space.

I was using WordPress 1.0.1. So, I had no access to plug-ins. I am currently upgrading to 1.2 to turn it into a plug-in rather than a hack.
I will post again once I have changed it.
Thanks,
Robert
ps (the upgrade hss, of course, temporarily removed the comment hack – if you still want to see it, it is at https://www.politicalbetting.com)