Grouper Developers Forum

[Tom Zeller <>]

Caching impacts ldappcng significantly. I had not investigated this before.

Our ehcache config files, ehcache.xml and grouper.ehcache.xml, are
daunting - so many caches to tune !

I wanted to cache "everything", so I decided ehcache.xml and
grouper.ehcache.xml should look like this :

<ehcache>
  <defaultCache
    maxElementsInMemory="500000"
    eternal="false"
    timeToIdleSeconds="120"
    timeToLiveSeconds="120"
    overflowToDisk="false"
  />
</ehcache>

Unfortunately, we sometimes hardcode ehcache parameters - which are
not overriden by the <defaultCache /> element.

So, adding a method to EhcacheController which uses <defaultCache/>
unless a configuration is specified :

  public Cache getCacheWithDefaults(String name) {
    this.initialize();
    if (!this.mgr.cacheExists(name) ) {
      mgr.addCache(name);
    }
    return mgr.getCache(name);
  }

and calling this method in the constructor of CachingAccessResolver,
CachingAttrDefResolver, and CachingNamingResolver

  public CachingAccessResolver(AccessResolver resolver) {
    super(resolver);
    this.cc = new EhcacheController();

    // init cache
    cc.getCacheWithDefaults(CACHE_HASPRIV);
  }

means that it would be possible to configure all caches using <defaultCache/>.

I also wrote a helper method to display ehcache statistics :

2011-03-25 00:07:23,408: [Timer-3] INFO
edu.internet2.middleware.ldappc.spml.PSPCLI.run(157) -  - End of
ldappc-ng execution : 36 ms
2011-03-25 00:07:23,411: [Timer-3] INFO
edu.internet2.middleware.ldappc.spml.PSPCLI.run(166) -  -
cache hit ratio  75%      3 hits      1 miss :
edu.internet2.middleware.grouper.FieldFinder.fieldCache
cache hit ratio  56%      5 hits      4 miss :
edu.internet2.middleware.grouper.GroupTypeFinder.typeCache
cache hit ratio  50%     10 hits     10 miss :
edu.internet2.middleware.grouper.subj.CachingResolver.FindByIdentifier
cache hit ratio  50%     10 hits     10 miss : SpmlDataConnector
cache hit ratio   0%      0 hits     15 miss :
edu.internet2.middleware.grouper.Field
cache hit ratio  67%      2 hits      1 miss :
edu.internet2.middleware.grouper.Group
cache hit ratio  75%     39 hits     13 miss :
edu.internet2.middleware.grouper.Member
cache hit ratio  67%      2 hits      1 miss :
edu.internet2.middleware.grouper.Stem

If you read this far ...

Armed with such statistics and the ease of configuring one
<defaultCache />, I think deployers of ldappcng would have an easier
time tuning caching to meet their needs.

I have not committed anything yet, let me know what you think.

TomZ