Horton

Re: BUG #14897: Segfault on statitics SQL request

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Dmitry Dolgov <9erthalion6@gmail.com>, Michael Paquier <michael.paquier@gmail.com>, Vincent Lachenal <vincent.lachenal@gmail.com>, PostgreSQL mailing lists <pgsql-bugs@postgresql.org>
Date: 2017-11-11T19:31:47Z
Lists: pgsql-bugs 
Andres Freund <andres@anarazel.de> writes:
> On 2017-11-11 12:54:29 -0500, Tom Lane wrote:
>> I think that would be better served by a flag like
>> MCXT_ALLOC_ALIGN_CACHELINE than by having the callers demand a
>> specific numeric alignment value --- it'd be a lot easier to make the
>> alignment match actual hardware requirements if it were being inserted
>> at one specific place.

> Specifying MCXT_ALLOC_ALIGN_CACHELINE rather than CACHELINE_ALIGNMENT
> doesn't seem to make it meaningfully harder to adjust. Or are you
> thinking of probing the hardware?

Yeah, the latter.  The two approaches seem pretty much equivalent if
you're assuming compile-time decisions, but if we ever wanted a run-
time decision, I think having a flag bit that's interpreted inside
MemoryContextAllocExtended would be easier to deal with.

			regards, tom lane

Commits

  1. Prevent int128 from requiring more than MAXALIGN alignment.

  2. Rearrange c.h to create a "compiler characteristics" section.