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help / color / mirror / Atom feedFrom: Robert Haas <[email protected]>
To: Tom Lane <[email protected]>
Cc: Etsuro Fujita <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: Ashutosh Bapat <[email protected]>
Cc: Rajkumar Raghuwanshi <[email protected]>
Cc: pgsql-hackers <[email protected]>
Subject: Re: Expression errors with "FOR UPDATE" and postgres_fdw with partition wise join enabled.
Date: Fri, 3 Aug 2018 10:14:04 -0400
Message-ID: <CA+TgmoZmVEx3piQ5TSKMyv55Rt8osEFeEUY1497SBXqnYMuu7g@mail.gmail.com> (raw)
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On Fri, Aug 3, 2018 at 10:07 AM, Tom Lane <[email protected]> wrote:
> Robert Haas <[email protected]> writes:
>> On Thu, Aug 2, 2018 at 4:25 PM, Tom Lane <[email protected]> wrote:
>>> Now, that's a bit of a problem for postgres_fdw, because it seems to
>>> insist on injecting WRVs even when the query text does not require any.
>>> Why is that, and can't we get rid of it?
>
>> I don't quite know what you mean here -- postgres_fdw does use
>> whole-row vars for EPQ handling, which may be what you're thinking
>> about.
>
> As far as I can see from the example that started this thread,
> postgres_fdw injects WRVs into a PWJ whether or not the query involves
> FOR UPDATE; that's why this bug is reproducible in a query without FOR
> UPDATE. But we shouldn't need any EPQ support in that case.
I might be missing something, but the original reproducer involves a
FOR UPDATE clause, and the expected regression test output in
postgres_fdw.out appears to show a whole-row var in the foreign scan's
target list only in those examples where a locking clause is present.
>> Honestly, I'm pretty impressed that we have added not one but two
>> members to the RelOptKind enum without as little collateral damage as
>> there has been.
>
> Color me a bit more skeptical about the bug density in that, given
> that enable_partitionwise_join is off by default; that means you're
> not getting a lot of testing.
You're hard to please.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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Subject: Re: Expression errors with "FOR UPDATE" and postgres_fdw with partition wise join enabled.
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