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List Archive: gentoo-performance
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To: gentoo-performance@g.o
From: Jesse Guardiani <jesse@...>
Subject: Re: Re: portage performance
Date: Fri, 30 Jul 2004 10:12:53 -0400
Brian Harring wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> 
>> The basic problem in searching is actually that it isn't implemented
>> smartly
>> in current portage. I have working (emerge -s like) code that is
>> blazingly
>> fast as it does not actually open all ebuilds.
> Searching works off of the cache for the most part, if a cache entry is
> stale, it's updated (eg the ebuild is opened and srced).
> Unless you're not checking the cache and updating it as you proceed,
> you're implementation ought to suffer the same limitation.
> 
>>  Doing description searching is
>> impossible to do fast without some kind of cache. I don't think
>> creating a
>> reliable cache for that is going to be a priority,
> There are 2 things that need to be done (in my books at least) to step
> up the speed of a description search-
> A) sql based cache backend, whether sqlite or mysql.

If it comes to this, I definately vote for sqlite. It's much faster than
mysql for embedded apps, and you don't have to worry about whether or not
the server is running.


>  Either that, or
> extend the flat cache to store the descriptions in a central index.

I think this is a good idea. AFAIK, this is what FreeBSD does. Perhaps
tinycdb could be used? (OCaml has a CDB module available too. You can
get it here: http://bleu.west.spy.net/~dustin/projects/ocaml/index.xtp
(BSD licence))


> B) alter the search description alg so that instead of stepping through
> each entry getting the description, we just state "give me all packages
> that have a description matching blar", and leave it up to the backend
> to decide what is the most efficient way to search.  With flat cache,
> we'd still have to go file by file; w/ a sql variant, it could take
> advantage of the appropriate syntax.

I personally prefer well designed hash table schemes. This is part of a
base operating system, so it needs to be extremely efficient. IMO, SQL
databases tend to encourage laziness. This is not to say that they don't
have their place, but I don't think they belong in a package management
system.

Still, it's a novel idea, I think. And offers a great deal of flexibility.


-- 
Jesse Guardiani, Systems Administrator
WingNET Internet Services,
P.O. Box 2605 // Cleveland, TN 37320-2605
423-559-LINK (v)  423-559-5145 (f)
http://www.wingnet.net



--
gentoo-performance@g.o mailing list

References:
portage performance
-- Jesse Guardiani
Re: portage performance
-- Jerry McBride
Re: portage performance
-- Jesse Guardiani
Re: Re: portage performance
-- Bart Alewijnse
Re: Re: portage performance
-- Paul de Vrieze
Re: Re: portage performance
-- Brian Harring
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Updated Jun 17, 2009

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