Horton

Re: [Proposal] Global temporary tables

Tomas Vondra <tomas.vondra@2ndquadrant.com>

View thread
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>, 曾文旌(义从) <wenjing.zwj@alibaba-inc.com>, Pavel Stehule <pavel.stehule@gmail.com>, Robert Haas <robertmhaas@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, 蔡松露(子嘉) <zijia@taobao.com>, "Cai, Le" <le.cai@alibaba-inc.com>, 萧少聪(铁庵) <shaocong.xsc@alibaba-inc.com>
Date: 2020-01-13T21:03:01Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. PageAddItemExtended(): Add LP_UNUSED assertion.

  2. Remove temporary files after backend crash

  3. Fix comment in indexing.c

  4. Fix failure to ignore leftover temp tables after a server crash.

On Mon, Jan 13, 2020 at 09:12:38PM +0100, Julien Rouhaud wrote:
>On Mon, Jan 13, 2020 at 05:32:53PM +0100, Tomas Vondra wrote:
>> On Mon, Jan 13, 2020 at 11:08:40AM +0300, Konstantin Knizhnik wrote:
>> >
>> >"if any code tried to access the statistics directly from the table,
>> >rather than via the caches".
>> >
>> >Currently optimizer is accessing statistic though caches. So this
>> >approach works. If somebody will rewrite optimizer or provide own
>> >custom optimizer in extension which access statistic directly
>> >then it we really be a problem. But I wonder why bypassing catalog
>> >cache may be needed.
>> >
>>
>> I don't know, but it seems extensions like hypopg do it.
>
>AFAIR, hypopg only opens pg_statistic to use its tupledesc when creating
>statistics on hypothetical partitions, but it should otherwise never reads or
>need plain pg_statistic rows.

Ah, OK! Thanks for the clarification. I knew it does something with the
catalog, didn't realize it only gets the descriptor.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services