[pacman-dev] tardb - Was: pacman cold caches performance, too much stat()ing
Allan McRae
allan at archlinux.org
Sat Dec 12 19:44:22 EST 2009
Dan McGee wrote:
> I think most of this thread is the wrong approach to the problem.
> Rather than try to meld the DB to fit pacman, we should just swap out
> DBs so it doesn't have these bad worst-case conditions.
>
> $ du -sh --apparent-size local/ sync/*
> 15M local/
> 8.4M sync/community
> 31K sync/community-testing
> 812K sync/core
> 11M sync/extra
> 302K sync/testing
>
> With those numbers in mind, we're talking about ~30 to ~35 MB of raw
> text data here. That is not a lot of data; most hard drives have at
> least ~30 MB/sec performance so this whole mess could be read in under
> a second if it was stored in a single file. So that would be one way
> of thinking about the issue differently.
Has anyone looked at the idea of using a single tarball for each db
recently? From memory, most of the issues of treating the reading from
archives in a style like a file stream had been solved when looking at
changelogs. Having said that, I have not looked at that code since it
was implemented...
Allan
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