Re: Commits 8de72b and 5457a1 (COPY FREEZE) - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: Commits 8de72b and 5457a1 (COPY FREEZE)
Date
Msg-id 20121206165539.GT5162@tamriel.snowman.net
Whole thread Raw
In response to Re: Commits 8de72b and 5457a1 (COPY FREEZE)  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Commits 8de72b and 5457a1 (COPY FREEZE)  (Jeff Davis <pgsql@j-davis.com>)
List pgsql-hackers
* Robert Haas (robertmhaas@gmail.com) wrote:
> I haven't looked at the committed patch - which seemed a bit

Disclaimer- neither have I, but..

When I last recall this discussion (likely in some bar in Europe), the
problem was also that an independent session would be able to:

a) see that the table exists (due to SnapshotNow being used for lookups)
b) see rows in the table

Part 'a' is something which I think would be good to fix (but hard),
and it sounds like this patch might make part 'b' happen, which I think
makes the part 'a' problem worse.  I'm guessing this isn't a problem for
the TRUNCATE case because the second session would still be looking at
the pre-TRUNCATE files on disk, right?  Is that reference to exactly
which files on disk to look at being used to address the CREATE problem
too..?

That said, I love the idea of having a way to drop tuples in w/o having
to go back and rewrite them three times..
Thanks,
    Stephen

pgsql-hackers by date:

Previous
From: "Kevin Grittner"
Date:
Subject: Re: Serious problem: media recovery fails after system or PostgreSQL crash
Next
From: Stephen Frost
Date:
Subject: Re: Commits 8de72b and 5457a1 (COPY FREEZE)