[pacman-dev] Tar backend for local db

Allan McRae allan at archlinux.org
Thu Nov 1 01:29:35 EDT 2012


On 01/11/12 15:25, Klaus-J. Wolf wrote:
> On Thu, Nov 1, 2012 at 6:12 AM, Allan McRae <allan at archlinux.org> wrote:
> 
>> Well...  I have a cunning plan...  How about we do both!
>>
>>
>> Have the local database in a tarball but also extracted.  All reading is
>> done from the tarball, so -Q operations would be fast due to not require
>> reading from lots of small files.
> 
> 
> If you use a separate database for faster access anyway, why not use a real
> fast format like sqlite or such alike? It could be a fragile format since
> the db would be regenerated after each access.

Because we already have all the code to read from tarballs - that is how
the sync dbs are handled.

> I personally see not much gain in this, it'd be a few milliseconds you save
> on the cost of making a simple task unnecessary complex (I am follower of
> the KISS principle :-).


# echo 3 > /proc/sys/vm/drop_caches
# time pacman -Qi pacman-git
...
real	0m13.242s

>From experience with the tar backend for sync databases, this would
decrease by at least 10 seconds.

Allan


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