Horton

Re: v13: Performance regression related to FORTIFY_SOURCE

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jeff Davis <pgsql@j-davis.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, pgsql-hackers@postgresql.org, Peter Geoghegan <pg@bowt.ie>
Date: 2020-06-06T01:50:53Z
Lists: pgsql-hackers 
Jeff Davis <pgsql@j-davis.com> writes:
> On Thu, 2020-06-04 at 16:35 -0400, Alvaro Herrera wrote:
>> If it is something worth worrying about, let's discuss what's a good
>> fix for it.

> While making a minimal test case for the GCC bug report, I found
> another surprisingly-small workaround. Patch attached.

Ugh :-( ... but perhaps you could get the same result like this:

-#define TapeBlockPayloadSize  (BLCKSZ - sizeof(TapeBlockTrailer))
+#define TapeBlockPayloadSize  (BLCKSZ - (int) sizeof(TapeBlockTrailer))

Or possibly casting the whole thing to int or unsigned int would be
better.  Point being that I bet it's int vs long that is making the
difference.

			regards, tom lane

Commits

  1. Fix platform-specific performance regression in logtape.c.