[Yum-devel] yum on an olpc machine (slooooooooooow)

[seth vidal]

On Wed, 2006-12-20 at 10:47 +0200, Panu Matilainen wrote:

> I wrote a quick-n-dirty sqlite "backend" for apt to see how things would 
> look like for another implementation (with totally different usage 
> patterns) of repodata.
> 
> The initial version performs so badly you wouldn't believe it :D
> 
> On 2.4GHz AMD64 the creation of dependency cache (which involves walking 
> over all packages and recording the dependency data to it's the memory 
> mapped dependency cache) takes over 3 MINUTES (!) for just FC6 core 
> data. With xml repodata, that's ~6.5s operation on this system, fully 
> reading filelists.xml info as well, which the sqlite version doesn't do at 
> all at this point.
> 
> After a bit of investigation, the major bottleneck here is that the 
> provides, requires, conflicts and obsoletes tables don't have index on 
> pkgKey. After creating those indexes, it's back to ~6.5s even with the 
> naive initial implementation.
> 
> I haven't done any timings on how those indexes would affect yum's usage 
> patterns, probably not *that* dramatic but it might be something to look 
> at.

I'm sure that better indexing would help some lookups rather a lot.

out of curiosity - how much does the size of the sqlite file go up when
the indexes are added?

-sv