Re: Should we cacheline align PGXACT? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Should we cacheline align PGXACT?
Date
Msg-id 19065.1471621560@sss.pgh.pa.us
Whole thread Raw
In response to Re: Should we cacheline align PGXACT?  (Alexander Korotkov <a.korotkov@postgrespro.ru>)
List pgsql-hackers
Alexander Korotkov <a.korotkov@postgrespro.ru> writes:
> On Fri, Aug 19, 2016 at 4:46 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> That's one mighty ugly patch.  Can't you do it without needing to
>> introduce the additional layer of struct nesting?

> That's worrying me too.
> We could use anonymous struct, but it seems to be prohibited in C89 which
> we stick to.
> Another idea, which comes to my mind, is to manually calculate size of
> padding and insert it directly to PGXACT struct.  But that seems rather
> ugly too.  However, it would be ugly definition not ugly usage...
> Do you have better ideas?

No, that was the best one that had occurred to me, too.  You could
probably introduce a StaticAssert that sizeof(PGXACT) is a power of 2
as a means of checking that the manual padding calculation hadn't
gotten broken.
        regards, tom lane



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