From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
---|---|
To: | Thomas Munro <thomas(dot)munro(at)gmail(dot)com> |
Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Does TupleQueueReaderNext() really need to copy its result? |
Date: | 2019-08-26 18:09:45 |
Message-ID: | CA+TgmobMoAMrYStOkMmewpP7UDT4+_HZMZ=MHYW=NE8uy12A4Q@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Fri, Aug 23, 2019 at 10:22 PM Thomas Munro <thomas(dot)munro(at)gmail(dot)com> wrote:
> Couldn't resist trying this, and it seems to work. Based on the
> comment "the buffer size is a multiple of MAXIMUM_ALIGNOF, and each
> read and write is as well", it should always work (though I wish
> shm_mq_receive_bytes()'s documentation would discuss message alignment
> explicitly if that's true). On the other hand, I doubt it makes a
> difference, so this is more of a question: is this the way it was
> supposed to work?
There's a comment in htup.h which says:
* * Separately allocated tuple: t_data points to a palloc'd chunk that
* is not adjacent to the HeapTupleData. (This case is deprecated since
* it's difficult to tell apart from case #1. It should be used only in
* limited contexts where the code knows that case #1 will never apply.)
I got scared and ran away.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2019-08-26 18:11:09 | Re: mingw32 floating point diff |
Previous Message | Laurenz Albe | 2019-08-26 18:08:05 | Re: Procedure support improvements |