I have practically just ran into this issue and found that the DefaultOptimizer is returning Long.MAX_VALUE for substring searches starting with "*"
Ideally when the given attribute has a index then we should just consider the size/count of the index, this results in better performance gain than when the Long.MAX_VALUE is used. I will commit this fix. otoh, I was able to gain 10x speed by configuring the ads-partitioncachesize property to a sufficiently high value w.r.t the total size of the partition (effectively keeping many entries in memory to avoid deserialization) On Mon, Mar 24, 2014 at 11:14 PM, Ernst Bech <[email protected]> wrote: > Ok I just did :) > > DIRSERVER 1965 > > I hope I didn't mess up too bad ;) > > With regards > > Ernst Bech > > > > Von: Emmanuel Lécharny <[email protected]> > An: [email protected], > Datum: 24.03.2014 17:45 > Betreff: Re: Antwort: Re: [ApacheDS] Slow search for a string > starting with "*" > > > > Le 3/24/14 4:26 PM, Ernst Bech a écrit : > > I have done a search for an unindexed attribut, another search for an > > unindexed attribute starting with a "*" and a search for an indexed > > attribute starting with a "*". > > All three took abount 5 secs on my hardware. > > > > So these test results seem to prove that the index is not used at all as > > > you pointed out. Will this have a chance to be improved later? > > OpenLDAP has the ability to configure an index as substring index which > > improves also searches starting (not only ending) with a "*" > drastically. > > Is this possible which ApacheDS too? > > This is defitively possible, and I would say it's easy to implement : > it's just a matter to create an index of the reverted value. > > How does it work ? Let's say you add a value MY-TEST for the CN > attribute. The normal CN index will refer to TEST, when the reverse > index will refer to TSET-YM. Now, looking for *TEST is just searching > the reverted index for TSET*. > > We have discussed this feature lengthly for years, but never decided to > implement it up to now. > > It woul be cool to create a JIRA proposing to add this feature. > > > -- > Regards, > Cordialement, > Emmanuel Lécharny > www.iktek.com > > > -- Kiran Ayyagari http://keydap.com
