patch to filterindex.c (ITS#228)

[benno@columbia.edu]

Full_Name: Benn Oshrin
Version: 1.2.4
OS: solaris 7
URL: http://www.columbia.edu/~benno/servers-slapd-back-ldbm-filterindex.diff
Submission from: (NULL) (128.59.39.90)


We noticed a situation where (with 400,000 records in our database) certain
searches would time out rather than respond quickly (even if there were no
entries to be found).  

For our database, cn=matheson\* timed out while cn=mathesom\* failed
immediately.  We traced this problem to faulty logic in 
substring_comp_candidates.

The patch (available at the URL provided) simply breaks the search if a NULL
intersection of search candidates is returned since at that point it is
impossible to find a match.