Attached is a patch that limits the range tested by horology to

Attached is a patch that limits the range tested by horology to
what is capable using integer-datatime timestamps. It does attempt
to exercise the maximum allowable timestamp range.
Also is a small error check when converting a timestamp from external
to internal format that prevents out of range timestamps from being
entered.

Files patched:
        Index: src/backend/utils/adt/timestamp.c
                Added range check to prevent out of range timestamps
                from being used.

        Index: src/test/regress/sql/horology.sql
        Index: src/test/regress/expected/horology-no-DST-before-1970.out
        Index: src/test/regress/expected/horology-solaris-1947.out
                Limited range of timestamps being checked to
                Jan 1, 4713 BC  to Dec 31, 294276

In creating this patch, I have seen some definite problems with integer
timestamps and how they react when used near their limits. For example,
the following statement gives the correct result:

        SELECT timestamp without time zone 'Jan 1, 4713 BC'
               + interval '109203489 days' AS "Dec 31, 294276";

However, this statement which is the logical inverse of the above
gives incorrect results:

        SELECT timestamp without time zone '12/31/294276'
             - timestamp without time zone 'Jan 1, 4713 BC' AS "109203489 Days";

John Cochran