Re: WIP patch for parallel pg_dump

Joachim Wieland wrote:
> Regarding snapshot cloning and dump consistency, I brought this up
> already several months ago and asked if the feature is considered
> useful even without snapshot cloning.

In addition, Joachim submitted a synchronized snapshot patch that looks
to me like it slipped through the cracks without being fully explored.
Since it's split in the official archives the easiest way to read the
thread is at
http://www.mail-archive.com/pgsql-hackers(at)postgresql(dot)org/msg143866.html

Or you can use these two:
http://archives.postgresql.org/pgsql-hackers/2010-01/msg00916.php
http://archives.postgresql.org/pgsql-hackers/2010-02/msg00363.php

That never made it into a CommitFest proper that I can see, it just
picked up review mainly from Markus. The way I read that thread, there
were two objections:

1) This mechanism isn't general enough for all use-cases outside of
pg_dump, which doesn't make it wrong when the question is how to get
parallel pg_dump running

2) Running as superuser is excessive. Running as the database owner was
suggested as likely to be good enough for pg_dump purposes.

Ultimately I think that stalled because without a client that needed it
the code wasn't so interesting yet. But now there is one; should that
get revived again? It seems like all of the pieces needed to build
what's really desired here are available, it's just the always
non-trivial task of integrating them together the right way that's needed.

--
Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
PostgreSQL Training, Services and Support www.2ndQuadrant.us