Re: hyrax vs. RelationBuildPartitionDesc

From: Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: hyrax vs. RelationBuildPartitionDesc
Date: 2019-04-08 08:56:53
Message-ID: bac37617-9e25-becf-00f3-d9c1007b9983@lab.ntt.co.jp
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On 2019/03/14 10:40, Amit Langote wrote:
> On 2019/03/14 5:18, Tom Lane wrote:
>> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>>> On Wed, Mar 13, 2019 at 3:14 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>>> Meanwhile, who's going to take point on cleaning up rd_partcheck?
>>>> I don't really understand this code well enough to know whether that
>>>> can share one of the existing partitioning-related sub-contexts.
>>
>>> To your question, I think it probably can't share a context. Briefly,
>>> rd_partkey can't change ever, except that when a partitioned relation
>>> is in the process of being created it is briefly NULL; once it obtains
>>> a value, that value cannot be changed. If you want to range-partition
>>> a list-partitioned table or something like that, you have to drop the
>>> table and create a new one. I think that's a perfectly acceptable
>>> permanent limitation and I have no urge whatever to change it.
>>> rd_partdesc changes when you attach or detach a child partition.
>>> rd_partcheck is the reverse: it changes when you attach or detach this
>>> partition to or from a parent.
>>
>> Got it. Yeah, it seems like the clearest and least bug-prone solution
>> is for those to be in three separate sub-contexts. The only reason
>> I was trying to avoid that was the angle of how to back-patch into 11.
>> However, we can just add the additional context pointer field at the
>> end of the Relation struct in v11, and that should be good enough to
>> avoid ABI problems.
>
> Agree that rd_partcheck needs its own context as you have complained in
> the past [1].
>
> I think we'll need to back-patch this fix to PG 10 as well. I've attached
> patches for all 3 branches.
>
> Thanks,
> Amit
>
> [1] https://www.postgresql.org/message-id/22236.1523374067%40sss.pgh.pa.us

Should I add this patch to Older Bugs [1]?

Thanks,
Amit

[1] https://wiki.postgresql.org/wiki/PostgreSQL_12_Open_Items

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Fujii Masao 2019-04-08 10:22:04 Re: reloption to prevent VACUUM from truncating empty pages at the end of relation
Previous Message Masahiko Sawada 2019-04-08 08:26:15 Re: reloption to prevent VACUUM from truncating empty pages at the end of relation