> >> I have to search for field5 in some DB files (30 or more >>for a total of > >> 50 GB of space and 150 M of records ). > > >> select * from main where field5= "AABBCCDD"; > > > > > Did you put an index on field5? > > Yes I use: > > CREATE UNIQUE INDEX main_index ON main (field2,field5,field7);
It's not the first field in the index, so I don't think it will use it for searching on "WHERE field5 = 'xxx' ". Try adding an index on field5 only CREATE UNIQUE INDEX main_indexf5 ON main (field5); > > > > Is a quite complex index used for eliminating duplicates, is it OK? I don't see any problem.
