Some techniques and trade-offs affecting large data base retrieval times

Abstract

T h i s p a p e r p r e s e n t s a t h e o r e t i c a l a n a l y s i s of c e r t a i n t e c h n i q u e s for o r g a n i z i n g l a r g e a m o u n t s of s t o r e d data to f a c i l i t a t e fast r e t r i e v a l of des i r e d i n f o r m a t i o n . The w e l l -k n o w n a c c e s s m e t h o d involving the use of an inverted file to provide multi-keyword access to records is analyzed and shown to significantly reduce retrieval time at the cost of increased file maintenance time. It is shown that further improvements in retrieval time can result from exploiting several techniques for compacting the inverted file, including the use of a bit-pattern representation of the inverted file records. In addition, a direct keyword access method is introduced which avoids the use of a large disk resident concordance/index for locating disk resident information by maintaining a relatively small core resident table.