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Re: [Wikipedia-l] what's being done about performance?

 

 

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lars at aronsson

Jul 13, 2002, 10:26 AM

Post #1 of 4 (222 views)
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Re: [Wikipedia-l] what's being done about performance?

On Sat, 13 Jul 2002, Daniel Mayer wrote:
> Much is now being done to remedy performance problems -- so I do believe what
> you said is needlessly rude (even if there is a grain of truth to it). This
> is an issue that has crept up upon the developers as new features were added
> -- many of which were asked for by the users.

If performance issues creep upon you, then you have not designed your
system for performance measurement and monitoring. This means you are
clueless. It is like driving a car without a speedometer, and being all
surprised when you are caught for speeding.

In the last week, my script made 410 attempts at 20 minute intervals to
reach the page http://www.wikipedia.com/wiki/Chemistry
Out of these, only 86% were served in less than 5 seconds. Five percent
of the calls timed out (my limit is 60 seconds). Now, this is far better
than the worst problems that Wikipedia saw in April or May, but it is
still pretty miserable. The non-English Wikipedias feature very similar
numbers.

The Sevilla project (http://enciclopedia.us.es/) serves 96% of all my
attempts in under 2 seconds, and 99% in under five seconds. This should
probably be attributed to luck rather than skill, but it helps move people
from the Spanish Wikipedia over to the breakout project.

> Software development seems to often work a lot like article development --

That's OK, but just like the basic Wiki software defines the concept of an
article (it can be written, reviewed, its history tracked, modified,
removed), the software should define a framework for new functionality
that can measure its impact on performance, and turn it on or off. Think
modules.


--
Lars Aronsson (lars [at] aronsson)
tel +46-70-7891609
http://aronsson.se/ http://elektrosmog.nu/ http://susning.nu/


neil.harris at mediachannel

Jul 13, 2002, 10:49 AM

Post #2 of 4 (218 views)
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Re: [Wikipedia-l] what's being done about performance? [In reply to]

Eliminating 'unsuccessful search' and 'special' pages from the count
gives the following stats:

Analysing 100,000 lines from the raw log with this filtering gives:

bin in seconds, total pages, cumulative percentage

0 57360 83.443651%
1 6929 93.523516%
2 2028 96.473720%
3 1034 97.977917%
4 640 98.908948%
5 314 99.365735%
6 157 99.594129%
7 81 99.711962%
8 61 99.800701%
9 46 99.867619%
10 18 99.893804%
11 12 99.911261%
12 16 99.934537%
13 13 99.953448%
14 6 99.962177%
15 6 99.970905%
16 6 99.979634%
17 2 99.982543%
18 0 99.982543%
19 3 99.986907%
20 2 99.989817%

summary 68741 hits in 41366.343 secs, avg = 0.601771039118
only 9 non-special pages took over 20 seconds: here they are:


20020713011714 28.783 /wiki/Historical_anniversaries
20020713012523 20.301 /wiki/Sport
20020713014205 23.161 /wiki/Federal_Standard_1037C
20020713014723 25.357
/w/wiki.phtml?title=Free_On-line_Dictionary_of_Computing/O
_-_Q&redirect=no
20020713015936 21.513
/w/wiki.phtml?title=Wikipedia:Bug_reports&action=history
20020713022203 25.252 /wiki/Free_On-line_Dictionary_of_Computing/L_-_N
20020713025105 29.975
/w/wiki.phtml?title=Free_On-line_Dictionary_of_Computing/E_-_H&redirect=no
20020713033140 20.802 /wiki/Feature_requests
20020713043401 41.392
/w/wiki.phtml?title=Complete_list_of_encyclopedia_topics/R&diff=78830&oldid=71983


It's interesting to note that random spidering hits 'special' pages
about 30% of the time.

Where the page accesses have been binned by the integer part of their
service time as recorded in the logs.

This is looking really good.

-------------------------------------------------

SUGGESTION #1:

Looking at the logs suggests that many of the worst results are
generated on the special page options with large counts -- particularly
the versions with count=5000.

Here's my proposal: we should not list the options with count > 500 for
users *that are not logged in*.

So, at the bottom of the orphans page, a logged in user would see

View (previous 50) (next 50) (20 | 50 | 100 | 250 | 500 | 1000 | 2500
| 5000).

and an casual browser (and any busy bots or spiders) would see

View (previous 50) (next 50) (20 | 50 | 100 | 250 | 500 ).

Random selection from the first list will search on average
50+50+20+50+100+250+500+1000+2500+5000 / 10 = 952 pages

Random selection from the second list will search on average
50+50+20+50+100+250+500 / 10 = 102 pages

a reduction in load of almost an order of magnitude.

Removing these big outlier loads may well take some of the strain off
ordinary page loads that happen to occur at the same time.

------------------------------------------------

SUGGESTION #2:

The 'Unsuccessful search' pages can be enormous. They accumulate all the
bad searches in a whole month. As Wikipedia becomes more popular, they
have become huge, and they now take a long time to load. We should make
these weekly or daily instead of monthly, and perhaps split up the old
ones using a script.

This will also have the effect of improving the 'most wanted' rating of
frequently missed searches, as currently only one instance a month counts.

Or perhaps they should be generated as a special page from the database?

---------------------------------------------------

Neil


neil.harris at mediachannel

Jul 13, 2002, 2:18 PM

Post #3 of 4 (218 views)
Permalink
Re: Re: [Wikipedia-l] what's being done about performance? [In reply to]

Having read Lars' post, to avoid confusion, perhaps I should point out
that my results in the previous mail were for beta.wikipedia.com.

Neil


lars at aronsson

Jul 13, 2002, 7:11 PM

Post #4 of 4 (217 views)
Permalink
Re: Re: [Wikipedia-l] what's being done about performance? [In reply to]

On Sat, 13 Jul 2002, Neil Harris wrote:
> Eliminating 'unsuccessful search' and 'special' pages from the count
> gives the following stats:
> Analysing 100,000 lines from the raw log with this filtering gives:

Where does this "raw log" come from? I don't think I've heard it
mentioned before. Is it from the real use of www.wikipedia.com or from
one of the test servers?


--
Lars Aronsson (lars [at] aronsson)
tel +46-70-7891609
http://aronsson.se/ http://elektrosmog.nu/ http://susning.nu/

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