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filter preprocessing for performance improvement

I wonder if it might be reasonable for the slapd frontend to do some preprocessing of search filters to recognize no-ops and such. Most specifically, any search filter of the form (&(objectclass=*)(filter2)) can be reduced to (filter2), right?

I have a problem in that the first time someone performs a search for 'objectclass=*' after slapd is restarted, the server is really bogged down for a while. Once the search has completed once, this is not a problem. I assume that's due to the IDL cache. However, I currently have to keep the server unavailable after restarting slapd for upwards of half an hour while I do an 'objectclass=*' search the first time.

I suppose a followup might be some preevaluation of ACLs before performing easily-recognized searches. For instance, the backend should not have to cope with a search for objectclass=* if the user doesn't have read access to anything as is often the case with an anonymous bind.

Eric Irrgang - UT Austin ITS Unix Systems - (512)475-9342