Re: pg_dump with both --serializable-deferrable and -j

On 2015-01-28 15:32:15 +0000, Kevin Grittner wrote:
> Andres Freund <andres@2ndquadrant.com> wrote:
> > ISTM that the check is just overzelous and/or needs to be moved into
> > ImportSnapshot(). There it then could be made to check if the exporting
> > xact was also deferrable.
> 
> That would be great if ImportSnapshot had access to that
> information; I don't see it, though.  Having pg_dump use repeatable
> read transactions for the processes that import the snapshot would
> work fine, as long as they are reading a snapshot which was
> captured by a serializable read only deferrable transaction.

Then add that information? The disk format for snapshot isn't persistent
across restarts, so we can just extend it.

I really don't like adding hacks like using a lower serializability
level than what's actually requested just because it happens to be
easier. Even if it's just in some backend.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
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