Alvaro Herrera <alvherre@commandprompt.com> writes:
> I observe that Paolo was using 8.1.0 and Oswaldo 8.1.1.
This appears to be the same bug already fixed in 8.1.3:
2006-01-29 12:27 tgl
* src/: backend/optimizer/path/indxpath.c,
backend/optimizer/path/pathkeys.c, include/optimizer/paths.h
(REL8_1_STABLE): Fix code that checks to see if an index can be
considered to match the query's requested sort order. It was
assuming that build_index_pathkeys always generates a pathkey per
index column, which was not true if implied equality deduction had
determined that two index columns were effectively equated to each
other. Simplest fix seems to be to install an option that causes
build_index_pathkeys to support this behavior as well as the
original one. Per report from Brian Hirt.
regards, tom lane