Re: Reasons to reorder results *within* a transaction?

Evan Jones wrote:
> I *know* that without an ORDER BY clause, the database is free to
> reorder results in any way it likes. However, I recently ran into a
> case where the *SAME* query was returning results in a different order
> *within* a single transaction, which surprised me (we fixed it by
> adding the missing ORDER BY). I would assume that once a transaction
> obtains a snapshot, all its read operations would return the same
> results.

Yes, the same results -- not necessarily in the same order.  For
instance, a synchronized scan might start at a different point of the
table.

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