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: 2017-09-26T22:49:39Z
Lists: pgsql-bugs, pgsql-hackers 
Andrew Dunstan <andrew.dunstan@2ndquadrant.com> writes:
> 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.

Yeah, that aspect of it was bothering me too: it's easy to say
"mark the function unsafe", but that only helps to the extent that
the function is used in queries where the planner has control of
whether to parallelize or not.  There's an awful lot of hard-wired
calls to I/O functions in our code, and I would not want to promise
that none of those are reachable in a parallel worker.

As for Stephen's concern, I had already looked at reverting 15bc038f9
earlier, and concluded that none of that code had changed significantly
since then.  There's some conflicts due to pgindent activity but I think
pulling it out will be a straightforward thing to do.

			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.