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From Emmanuel Lécharny <>
Subject Re: Search performance potential improvements
Date Sat, 07 Sep 2013 06:55:35 GMT
Some more : in SubtreeScopeEvaluator.evaluate() and
OneLevelScopeEvaluator.evaluate(), we also check if the entry we will
work on is an alias :

        if ( null != db.getAliasIndex().reverseLookup( id ) )
            return false;

Replacing it with a cache check will again save 10%.

FTR, by commenting this piece of code and the same in
DefaultSearchEngine, I reach 26 364 search/s on Mavibot (it was around
19 000 before).

Also note that since I started to work on performances, one month ago,
the gain is quite significant : up to 26 364 search/s from 5091/s... And
we still have some other ways to gain somemore performance :-)

JDBM performances are 3 times behind (6 381/s) but it was 654/s on the
very first tests.

Le 9/4/13 12:12 PM, Emmanuel Lécharny a écrit :
> Hi guys,
> I just came back from a short week of excellent vacations, and I spent
> the last two days looking at the search operation.
> Just before I left, I thought that the entry was cloned for no reason.
> The fact is that we do modify the entry before returning it, so we must
> modify a copy of the cached entry, otherwise we can have some really
> nasty bugs in other parts (the entry is cached, so we can't simply
> modify it).
> OTOH, I discovered that we do a costly check in the
> DefaultSearchEngine.computeResults() method : we check if the search
> BaseDN is an alias by looking into the Alias index. Not doing this check
> imrpove the performance for around 15%. I'm pretty sure we can avoid
> looking into the index, as soon as we already have a cache of the
> existing aliases. The pb is that it's just a cache, and if the alias is
> not in the cache, we have to fetch the alias index. This become a pb
> when we have a lot of aliases, something unlikely to happen.
> I will try to think about a better solution.

Emmanuel Lécharny 

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