Wikipedia:Historical archive/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 inability to see pages.
 * Readers are frustrated in their inability to edit pages. Sometimes they lose their work.

Possible Causes

 * Saving pages with many links is slow
 * 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

(Discussion moved from Village pump)

False server down
I couldn&#8217;t access the website (like it was down) for 2 or 3 hours until just now. I thought it&#8217;s just another server thing until I tried another public computer (all in the same room), and it worked fine. Then I closed my broswers (I tried in both IE & NE), and it worked, but pages appear quite slowly when I log in, and very fast when I&#8217;m Anon. This false down is really annoying, as I was in the middle of typing something when it suddenly occurred, but I couldn&#8217;t go anywhere because I&#8217;m using a public comp, so I needed to hog the comp instead of going elsewhere.


 * Q: What caused this false "personalized" down?
 * Q2: Why the slow-fast regi-Anon difference?

--Menchi 20:36 16 Jul 2003 (UTC)


 * I'm not sure about the "false down", but Q2 is easy -- caching. Because all anon. users see the same HTML, it can easily be cached. If another anon. user has viewed the page recently, no DB access is required. The cached HTML is also compressed, whereas the HTML generated for logged in users is not. -- Tim Starling 00:25 17 Jul 2003 (UTC)


 * Can I set my preferences so as to get the cached HTML, if my settings are identical to those of an anon user? Martin 09:59 17 Jul 2003 (UTC)


 * No, but you can just log out. :) It stores the entire page, including the sidebar and bits in the corner, so you wouldn't get things like the 'move page' link, ability to watch pages, etc.

Slowdowns - blame the foreigners!
move to lag

I just realized something regarding the consistent wikipedia slowdowns. The features that we have turned off to keep the english wikipedia from slowing down, are on on the other pedias. Could this be contributing to the slow downs? MB 14:33 18 Jul 2003 (UTC)


 * They have been turned off on Wikiquote so perhaps they are still on and causing slowdown on the other language pedias? Nanobug 17:46, 19 Sep 2003 (UTC)