On mån, 2010-03-01 at 15:30 -0500, Jaime Casanova wrote: > so IMMUTABLE = DETERMINISTIC NO SQL, > STABLE = DETERMINISTIC READS SQL DATA > VOLATILE = NOT DETERMINISTIC MODIFIES SQL DATA
It might be tempting to create such a mapping, but there could be a number of pitfalls, especially if you define it as a commutative equivalence rather than say logical implications. For example, MODIFIES SQL DATA ought to imply VOLATILE, but the reverse is not true. When the volatility attribute was introduced, we briefly looked at the standard "deterministic" attribute, but concluded that it would be better to create settings that describe how the PostgreSQL planner/executor works instead of some abstract setting that is descriptive but doesn't actually help optimizing the query. We might actually end up with all three groups of settings at some point. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
