Horton

Re: Declarative partitioning - another take

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Amit Langote <amitlangote09@gmail.com>, Dmitry Ivanov <d.ivanov@postgrespro.ru>, Michael Paquier <michael.paquier@gmail.com>, Andres Freund <andres@anarazel.de>, Erik Rijkers <er@xs4all.nl>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Pg Hackers <pgsql-hackers@postgresql.org>, pgsql-hackers-owner@postgresql.org
Date: 2016-12-21T04:42:59Z
Lists: pgsql-hackers 
On Tue, Dec 20, 2016 at 9:14 PM, Amit Langote
<Langote_Amit_f8@lab.ntt.co.jp> wrote:
> On 2016/12/21 1:45, Alvaro Herrera wrote:
>> Robert Haas wrote:
>>> On Tue, Dec 20, 2016 at 10:27 AM, Alvaro Herrera
>>> <alvherre@2ndquadrant.com> wrote:
>>>> Even if we decide to keep the message, I think it's not very good
>>>> wording anyhow; as a translator I disliked it on sight.  Instead of
>>>> "skipping scan to validate" I would use "skipping validation scan",
>>>> except that it's not clear what it is we're validating.  Mentioning
>>>> partition constraint in errcontext() doesn't like a great solution, but
>>>> I can't think of anything better.
>>>
>>> Maybe something like: partition constraint for table \"%s\" is implied
>>> by existing constraints
>>
>> Actually, shouldn't we emit a message if we *don't* skip the check?
>
> Scanning (aka, not skipping) to validate the partition constraint is the
> default behavior, so a user would be expecting it anyway, IOW, need not be
> informed of it.  But when ATExecAttachPartition's efforts to avoid the
> scan by comparing the partition constraint against existing constraints
> (which the user most probably deliberately added just for this) succeed,
> that seems like a better piece of information to provide the user with,
> IMHO.  But then again, having a message printed before a potentially long
> validation scan seems like something a user would like to see, to know
> what it is that is going to take so long.  Hmm.
>
> Anyway, what would the opposite of Robert's suggested message look like:
> "scanning table \"%s\" to validate partition constraint"?

Maybe: partition constraint for table \"%s\" is implied by existing constraints

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Fix typo.

  2. Document trigger-firing behavior for inheritance/partitioning.

  3. Fire per-statement triggers on partitioned tables.

  4. Set ecxt_scantuple correctly for tuple routing.

  5. Fix interaction of partitioned tables with BulkInsertState.

  6. Avoid core dump for empty prepared statement in an aborted transaction.

  7. Fix some problems in check_new_partition_bound().

  8. Remove unnecessary arguments from partitioning functions.

  9. Fix reporting of constraint violations for table partitioning.

  10. Fix tuple routing in cases where tuple descriptors don't match.

  11. Invalid parent's relcache after CREATE TABLE .. PARTITION OF.

  12. Doc: improve documentation about inheritance.