yum 3.2.23 more than 10x slower than 3.2.21?!

[Joe Nall]

On Jun 26, 2009, at 10:03 AM, Seth Vidal wrote:

>
>
> On Fri, 26 Jun 2009, Roberto Ragusa wrote:
>
>> It is really CPU intensive. I see some unicode related stuff in the  
>> changelog
>> and my memory goes to years ago (RedHat 8?) when the UTF8 enabled  
>> grep
>> got a similar slowdown (the lib was then improved after that).
>>
>> Hmmmmm, made other experiments....
>> Really weird.
>>
>> #time yum list updates --disablerepo=\* --enablerepo=ROB10\*
>> (less than 3 seconds)
>>
>> #time yum list updates --disablerepo=\* --enablerepo=updates
>> (less than 3 seconds)
>>
>> #time yum list updates --disablerepo=\* --enablerepo=ROB10\*  -- 
>> enablerepo=updates
>> (more than one minute)
>>
>> ROB10\* is some local repositories, containing mirrored stuff from  
>> some
>> repositories, _including fedora_updates_, so the same rpms are  
>> found in two
>> different repositories. How can this trigger such a slowdown, I  
>> don't know.
>>
>> I have to correct what I said before, the time is not always spent
>> on read64() and gettimeofday(); there is a lot of strace-silent  
>> activity
>> (just spurious brk() calls).
>>
>> Maybe something like hashing of some data structure is taking a  
>> really bad
>> direction?
>
>
> run:
>
> time yum -d 3 --disablerepo=\* --enablerepo=ROB10\*  \
>           --enablerepo=updates  list updates | grep 'time:'
>
>
> and post that output.


I disabled all repos and individually enabled one repo at a time. Each  
individual repo performance was excellent (couple of seconds). When I  
included two repos, I start to see the problem. local-mirror-updates  
is a a low cost (500) local rsync mirror on a GbE network.

[root at fast ~]# time yum -d 3 --disablerepo=\* --enablerepo=local- 
mirror-updates --enablerepo=updates list updates | grep 'time:'
Config time: 0.040
repo time: 0.000
pkgsack time: 39.956
rpmdb time: 0.002
up:Obs Init time: 0.054
up:simple updates time: 0.047
up:obs time: 0.002
up:condense time: 0.000
updates time: 0.388

real	0m40.547s
user	0m40.253s
sys	0m0.195s