Wikipedia:Lag

Lag Log

• Pursuant to lag complaints on the mailing list (plus my own observation of 25 second lags), I locked the database for 3 minutes. There was a slight improvement, but it's still slow. --Uncle Ed 18:20 Jan 22, 2003 (UTC)

• No access for nearly four (4) hours today! From 12:44 to 16:37 (US East Coast time). No idea what caused it, but when Jimbo found out that the server wasn't responding he got Jason to restart it. --Uncle Ed 22:10 Dec 12, 2002 (UTC)

• Access slowed from a crawl to a halt this morning, US East Coast time at around 11:20, so I locked the database for about 10 minutes, to see if that would speed it up again. It seems better to me now. --Uncle Ed 16:27 Dec 10, 2002 (UTC)

Lagging Problem

Often the Wikipedia server gets into a mode where it does not respond for periods of over one minute -- a huge amount of time in the Internet world.

Yeah, like today: 2 hours! Sheesh.

Effects of lagging

• Readers are frustrated in their ability to see pages.
• Readers are frustrated in their ability to edit pages. Sometimes they lose their work.

Possible Causes

• Saving pages with many links is slow (http://sourceforge.net/tracker/index.php?func=detail&aid=584443&group_id=34373&atid=411192)
• Someone running a long query?
• Some guy in Arkansas downloading the entire site, including diffs and user contributions pages with varying numbers of return results set, with a spider that doesn't have a throttle control (now blocked)

Proposed Solutions

Note: if a solution isn't keyed to a cause, it's not likely to really solve anything.

• lagging Does anybody know why the site is lagging so bad? 129.186.80.116[?] 17:53 Oct 29, 2002 (UTC) Yes someone plz direct me to or create a tech page which explains the lag. Lir 17:59 Oct 29, 2002 (UTC) Don't remove this until somebody tells me where else I can go to put things like this. Lir 18:11 Oct 29, 2002 (UTC)

I've noticed it too. Try Talk:Main_Page. Its been going on for days. Sometimes causing me server not found errors. But how do you know what it is? I assume just too many people online at the same time. It goes away at night. Rlee0001 18:19 Oct 29, 2002 (UTC)

MySQL has really crappy table locking, and blocks everything when certain slow operations are being done. We're looking into replacing it with Postgresql, which is said to scale better. But, first I have to adapt the code, change the table definitions, make sure it works on my home server, set up a test installation here before we go converting hundreds of megabytes of databasey goodness willy-nilly. --Brion 21:16 Oct 29, 2002 (UTC)

You might also want to look at doing "What links here" on pages linked to by every single one of Ram-Man's 36000 or so pages... these will predictably lock up for ages. I imagine that these and similar links are being hit periodically... -- Anon.

I am almost positive that "saving pages with too many links" is not the problem, unless they are external links or something like that. Yesterday, I updated the "Multiple-Place Names" page. It has over 1,200 links and it took a second or too longer because it was a large page, but not a serious lag. If *that* page doesn't cause any trouble, then no page should. -- Ram-Man

Inclined to concur. I have a few pages with a large number of links (e.g. Norse mythology) which have dependants and dependancies in abundance and they seem as good as gold. user:sjc