Optimizing the Performance of a Relational Algebra Database Interface
An approach for implementing a "smart" interface
to support a relational view of data is proposed. 
 The basic idea is to employ automatic programming techniques
so that the interface analyzes and efficiently 
refines the high level query specification supplied by
the user.  A relational algebra interface, called 
SQUIRAL, which was designed using this approach, is described
in detail. SQUIRAL seeks to minimize query 
response time and space utilization by: (1) performing
global query optimization, (2) exploiting disjoint 
and pipelined concurrency, (3) coordinating sort orders
in temporary relations, (4) employing directory 
analysis, and (5) maintaining locality in page references.
 Algorithms for implementing the operators 
of E. F. Codd's relational algebra are presented, and
a methodology for composing them to optimize the 
performance of a particular user query is described.
CACM October, 1975
Smith, J. M.
Yen-Tang Chang, P.
