RFC: Re: [Yum-devel] How to make depsolving twice as fast...

[Tim Lauridsen]

seth vidal wrote:
> On Sat, 2008-03-29 at 16:08 -0400, James Antill wrote:
>> On Sat, 2008-03-29 at 09:11 -0400, seth vidal wrote:
>>> On Sat, 2008-03-29 at 02:22 -0400, James Antill wrote:
>>>> Maybe this was more obvious to others, but:
>>>>
>>>> yum --enablerepo=development upgrade
>>>>
>>>> ...takes about twice as long (and uses about 100MB more) as:
>>>>
>>>> yum --disablerepo=* --enablerepo=development upgrade
>>>>
>>> well, you are diminishing the number of packages to search through by
>>> about half.
>>  Yeh, I tried to do some code so we can have "newest pkgs" data directly
>> in MetaSack so the sqlitesack code could say things like "if this pkg
>> isn't the newest, skip the requires/provides searches" ... but it wasn't
>> pretty, and didn't save much (roughly 10% RSS / 5% CPU).
>>
>>  So I had another idea, just do something like the above (which is
>> probably what the user would do if they knew) ... have a configuration
>> option in the repo section that says "when this repo. is enabled, these
>> other repos should be disabled".
>>
>>  With the following patch, I added the following (in the corresponding
>> repo. sections):
>>
>> [development]
>> auto_disable_repos = fedora, updates, updates-testing
>>
>> [development-debuginfo]
>> auto_disable_repos = fedora-debuginfo, updates-debuginfo, updates-testing-debuginfo
>>
>>
>> [livna-development]
>> auto_disable_repos = livna
>>
>> [livna-development-debuginfo]
>> auto_disable_repos = livna-debuginfo
>>
>> ...gives me about 33% CPU (30 secs from 45) 33% RSS (163MB from 243, VSZ
>> also down by about 80MB to 393MB from 473MB)[1].
>>
>>  Patch is at:
>>
>>  http://people.redhat.com/jantill/yum/patches/auto-disable-repos.patch
>>
>> ...the way it is there you can still do:
>>
>>  --enablerepo=development --enablerepo=fedora
>>
>> ...if you really want to.
>>
>>
>>  So RFC time:
>>
>> . Anyone think the feature is too magic? Any suggestions to make it less
>> magic (add option to disable, add log messages saying what we are
>> doing?)
>>
>> . Anyone hate the config. variable name?
>>
>> . Anyone want the option to be more powerful? Ie. if you have
>> updates-debuginfo on, and you do --enablerepo=updates-testing we
>> probably want to turn updates-testing-debuginfo on.
>>
>>
> 
> Seriously, I think this not something worth adding to yum. Maintaining
> these lists is doom, especially as more repos get added/subtracted and
> frankly if a user complains about yum being slow or taking up too much
> memory and they're loading repos they aren't using then I think that
> falls into the category of "Dr, it hurts when I do this! Don't do that,
> then."
> 

I agree with Seth on this one, i don't help people in the day to use of yum.


Tim