$Header: /cvsroot/pgsql/src/backend/access/nbtree/README,v 1.2 2000/07/2106:42:32 tgl Exp $

$Header: /cvsroot/pgsql/src/backend/access/nbtree/README,v 1.3 2000/07/2122:14:09 tgl Exp $

This directory contains a correct implementation of Lehman and Yao's

high-concurrency B-tree management algorithm (P. Lehman and S. Yao,

Notes to operator class implementors:

+ With this implementation, we require the user to supply us with

a procedure for pg_amproc. This procedure should take two keys

A and B and return < 0, 0, or > 0 if A < B, A = B, or A > B,

respectively. See the contents of that relation for the btree

access method for some samples.

+ With this implementation, we require each supported datatype to supply

us with a comparison procedure via pg_amproc. This procedure must take

two nonnull values A and B and return an int32 < 0, 0, or > 0 if A < B,

A = B, or A > B, respectively. See nbtcompare.c for examples.