Horton

Re: [HACKERS] BUG #14825: enum type: unsafe use?

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Cc: Stephen Frost <sfrost@snowman.net>, Bruce Momjian <bruce@momjian.us>, "David E. Wheeler" <david@justatheory.com>, Christophe Pettus <christophe.pettus@pgexperts.com>, pgsql-bugs@postgresql.org, pgsql-hackers@postgresql.org
Date: 2017-09-27T18:52:54Z
Lists: pgsql-bugs, pgsql-hackers 
Andrew Dunstan <andrew.dunstan@2ndquadrant.com> writes:
> At this stage on reflection I agree it should be pulled :-(

That seems to be the consensus, so I'll go make it happen.

> I'm not happy about the idea of marking an input function as not
> parallel safe, certainly not without a good deal of thought and
> discussion that we don't have time for this cycle.

I think the way forward is to do what we had as of HEAD (984c92074),
but add the ability to transmit the blacklist table to parallel
workers.  Since we expect the blacklist table would be empty most of
the time, this should be close to no overhead in practice.  I concur
that the idea of marking the relevant functions parallel-restricted is
probably not as safe a fix as I originally thought, and it's not a
very desirable restriction even if it did fix the problem.

			regards, tom lane

Commits

  1. Revert to 9.6 treatment of ALTER TYPE enumtype ADD VALUE.

  2. Remove heuristic same-transaction test from check_safe_enum_use().

  3. Use a blacklist to distinguish original from add-on enum values.

  4. Add support for coordinating record typmods among parallel workers.