On 2020-01-10 14:41, Robert Haas wrote:
This rule very nearly matches the current behavior: it explains why temp table operations are allowed, and why ALTER SYSTEM is allowed, and why REINDEX etc. are allowed. However, there's a notable exception: PREPARE, COMMIT PREPARED, and ROLLBACK PREPARED are allowed in a read-only transaction. Under the "doesn't change pg_dump output" criteria, the first and third ones should be permitted but COMMIT PREPARED should be denied, except maybe if the prepared transaction didn't do any writes (and in that case, why did we bother preparing it?). Despite that, this rule does a way better job explaining the current behavior than anything else suggested so far.
I don't follow. Does pg_dump dump prepared transactions? -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
