Re: pg_verify_checksums and -fno-strict-aliasing - Mailing list pgsql-hackers

From Tom Lane
Subject Re: pg_verify_checksums and -fno-strict-aliasing
Date
Msg-id 28226.1535727306@sss.pgh.pa.us
Whole thread Raw
In response to Re: pg_verify_checksums and -fno-strict-aliasing  (Michael Paquier <michael@paquier.xyz>)
Responses Re: pg_verify_checksums and -fno-strict-aliasing
List pgsql-hackers
Michael Paquier <michael@paquier.xyz> writes:
> On Thu, Aug 30, 2018 at 07:37:37PM -0400, Tom Lane wrote:
>> Anyway, I'll work on a patch for that, unless you were on it already?

> I have begun working on that and am less than halfway through it as I
> needed a fresh problem, however I am not sure I would be able to finish
> it today, perhaps tomorrow...  If you have time and want to press on as
> 11 would release soon, of course feel free to wrap up more quickly than
> I can.

Some of these places might be performance-critical enough that adding
a palloc/pfree cycle would not be nice.  What I was considering doing
was inventing something like

typedef union PGAlignedBuffer
{
    char    data[BLCKSZ];
    double    force_align;
} PGAlignedBuffer;

and replacing plain char[] variables with that as appropriate.
We might need one for XLOG_BLCKSZ too.

Since this'd be used in frontend as well as backend, it'd likely
have to end up in c.h, which is slightly annoying but not really
a big deal as long as we pick a nonconflicting type name.

            regards, tom lane


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