[Moin-user] Argument order for search

Mail@Heavy.ch mail at heavy.ch
Mon Mar 16 17:25:14 EDT 2009


Dr. Uwe Werner schrieb:
> Hello Fellow-MoinMoiners!
> I was wondering if there is a difference in performance between
> (1) <<FullSearch(category:CategoryName title:Prefix-)>>
> and
> (2) <<FullSearch(title:Prefix- category:CategoryName)>> ???
if you talk about xapian, I think there is no different, because all
keywords/data are stored in a indexes/database... but maybe some core
dev knows better. the normal moinmoin search is slow. don't use it for
bigger wikies.

> Does category search actually open the page and read until the last  
> line is reached in order to check the category? If so, then I presume   
> (2) is faster because checking the name of a page (actually most  
> pages) and excluding it from the subsequent is a quicker thing than  
> finding categories. Is this correct?

again with xapian search sure not! Because xapian use an own database
for the indexes (http://xapian.org/docs/quickstart.html) so no need for
open/reading every page.

about the question for the querparser I do not know.. some moin-dev
should know.

What's about the intern "slow" moinmoin search don't know... it's anyway
to slow if you start to have a wiki with more then a few hundred pages.
> The wiki in question is still small. Does someone have "empirical"  
> evidence -- or know the internals?

it's not only depend on the wiki size (pagecounts), more important is
how your users use the wik, how many traffic you will have, how fast is
your machine, are your pages full with attachment to download or only
single text pages, etcetera.

maybe you have to specific how big your wiki will be, how many
concurrent users you will have, how many search in a minutes, etc.. so
somebody can say someting...

the only limit is that some filesystem (like ext3) only supporting
32'000 subdirectorys and I also would say more then 15'/20'000 Pages
would be realy heavy. Maybe have a look at the ext4
or some other filesystems (e.g. xfs)

in generaly:
1. use apache (or even a more lighter webserver) with wsgi
2. use xapain for search
3. try to tweak/tune your filesystem
4. add a lot of memory to your machine,
5. use fast harddisk with some raid
6. etcetera...

see here: http://moinmo.in/HowTo/Tune%20Performance

> BTW when is the cache in the "Cached" search version up-to-date?
as far as i know "caching" means only the result (the page itself), and
not the search query. so if somebody add a new page you need to
"refresh" to see this page...

btw. there is a page on the wiki http://moinmo.in/PerformanceProposals
but it is a bit outdated.

hope it helps a bit...


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