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Caching svn_fs_t and friends

From: Blair Zajac <blair_at_orcaware.com>
Date: Wed, 03 Apr 2013 16:25:01 -0700

Hi guys,

Saw my name mentioned in IRC regarding caching svn_*_t.

In our custom svn RPC server that exposes svn_repos_t and svn_fs_t, we
cache svn_repos_t, svn_fs_root_t (for both revisions and txns).

I pulled some stats from our live server, here is the svn_repos_t cache:

Max=238
N=238
InUse=0
Lookups=209959446
CacheHits=209958192
CacheMisses=1254
CacheHitRatio=0.999994
Evictions=1016

ConstructionAge(
   N=238
   min=04:22:19.316771
   25%=1d07:05:44.297955
   50%=1d22:38:44.728577
   90%=6d05:40:09.023494
   95%=6d05:47:27.417303
   99%=7d05:34:32.500303
   max=7d06:48:08.218891)

LastUseAge(
   N=238
   min=0.000316
   25%=38:54.439219
   50%=38:54.843007
   90%=1d22:08:15.423188
   95%=1d22:09:46.925353
   99%=1d22:09:46.925165
   max=1d22:10:05.678702)

NumberServantsPerId(
   N=119
   min=1
   25%=1
   50%=1
   90%=2
   95%=3
   99%=10
   max=76)

So our oldest svn_repos_t is 7 days and 6 hours old, which is basically
as old as the process, so we can cache them indefinitely. Actually, I
size the cache to 2*number repos.

Blair
Received on 2013-04-04 01:26:14 CEST

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