Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation) - Mailing list pgsql-hackers

From Robert Haas
Subject Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation)
Date
Msg-id CA+TgmoYFPkVHAxVm6Eo+feUJBxY-p3s6RG6TavfXViGYqvuFSg@mail.gmail.com
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In response to Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation)  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: [HACKERS] Parallel tuplesort (for parallel B-Tree indexcreation)  ("Tels" <nospam-abuse@bloodgate.com>)
Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation)  (Peter Geoghegan <pg@bowt.ie>)
List pgsql-hackers
On Mon, Feb 5, 2018 at 1:03 PM, Peter Geoghegan <pg@bowt.ie> wrote:
> It certainly is common. In the case of logtape.c, we almost always
> write out some garbage bytes, even with serial sorts. The only
> difference here is the *sense* in which they're garbage: they're
> uninitialized bytes, which Valgrind cares about, rather than byte from
> previous writes that are left behind in the buffer, which Valgrind
> does not care about.

/me face-palms.

So, I guess another option might be to call VALGRIND_MAKE_MEM_DEFINED
on the buffer.  "We know what we're doing, trust us!"

In some ways, that seems better than inserting a suppression, because
it only affects the memory in the buffer.

Anybody else want to express an opinion here?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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