Howard Chu wrote: > Michael StrÃder wrote: >> HI! >> >> I'm trying to retrieve change events from accesslog DB (all with today's >> RE24). I tried searching with this filter: >> >> (&(reqDN=cn=Test-Mail-Gruppe 1,dc=example,dc=com)(reqStart<=20120413180000Z)) >> >> This turned out to be quite slow though. reqDN is indexed and there are only >> two possible entries. Using a filter reqStart>= even when negated with (!()) >> is pretty fast. > > Is reqStart indexed? Yes, eq-indexed of course. >> I really wonder why that is. > > Obviously, for any database that has been around for even a short while, there > will be far fewer records with a date newer than [today's date] as opposed to > older than then. But there were only three entries matching (reqDN=cn=Test-Mail-Gruppe 1,dc=example,dc=com) anyway and reqDN is also eq-indexed and finding them with this filter is pretty fast. Some more examples where reqDN-index is obviously not used but reqStart-index should be used in both cases: Quite fast although I would have expected an significant slow down because of negation filter: (&(reqDN:dnSubtreeMatch:=ou=Groups,dc=example,dc=com)(reqStart>=20120313072338Z)(!(reqStart>=20120413075657Z))) Almost identical but very slow compared to the example above: (&(reqDN:dnSubtreeMatch:=ou=Groups,dc=example,dc=com)(reqStart>=20120313072338Z)(reqStart<=20120413075657Z)) I can't explain this based on index configuration. Maybe there's something handled differently with <= compared to >=? Ciao, Michael.
Description: S/MIME Cryptographic Signature