Re: tracking commit timestamps

Petr Jelinek wrote:

> This is good point, we are not too late in the cycle that LSN couldn't be
> added later if we find that it is indeed needed (and we don't have to care
> about pg_upgrade until beta).

I think we're overblowing the pg_upgrade issue. Surely we don't need to
preserve commit_ts data when upgrading across major versions; and
pg_upgrade is perfectly prepared to remove old data when upgrading
(actually it just doesn't copy it; consider pg_subtrans or pg_serial,
for instance.) If we need to change binary representation in a future
major release, we can do so without any trouble.

--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services