| From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
|---|---|
| To: | Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andres Freund <andres(at)anarazel(dot)de>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, Rushabh Lathia <rushabh(dot)lathia(at)gmail(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Corey Huinker <corey(dot)huinker(at)gmail(dot)com> |
| Subject: | Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation) |
| Date: | 2018-02-06 21:14:26 |
| Message-ID: | CAH2-Wzm7E2p1WE2vzbZHmx1jJbQRY=NniQmJ5=Xxh9bX43sM5A@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Feb 6, 2018 at 1:04 PM, Tomas Vondra
<tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> Did you do a test with "-O0"? In my experience that makes valgrind tests
> much more reliable and repeatable. Some time ago we've seen cases that
> were failing for me but not for others, and I suspect it was due to me
> using "-O0".
FWIW, I use -O1 when configure is run for Valgrind. I also turn off
assertions (this is all scripted). According to the Valgrind manual:
"With -O1 line numbers in error messages can be inaccurate, although
generally speaking running Memcheck on code compiled at -O1 works
fairly well, and the speed improvement compared to running -O0 is
quite significant. Use of -O2 and above is not recommended as Memcheck
occasionally reports uninitialised-value errors which don’t really
exist."
The manual does also say that there might even be some problems with
-O1 at a later point, but it sounds like it's probably worth it to me.
Skink uses -Og, FWIW.
--
Peter Geoghegan
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