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Re: [HACKERS] regressin failure on latest CVS

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: ohp(at)pyrenet(dot)fr
Cc: Rocco Altier <RoccoA(at)Routescape(dot)com>,Michael Glaesemann <grzm(at)myrealbox(dot)com>,pgsql-patches(at)postgresql(dot)org, pgsql-hackers(at)postgresql(dot)org
Subject: Re: [HACKERS] regressin failure on latest CVS
Date: 2005-07-23 17:15:12
Message-ID: 200507231715.j6NHFC523531@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-patches
Yes, we have seen those stat tests fail randomly.  We are working on a
solution.


---------------------------------------------------------------------------

ohp(at)pyrenet(dot)fr wrote:
> I think the patch is ok now,   intervall is not failing anymore as of
> 18:50 CET.
> 
> However stats fails.
> regression.diffs:
> 
> *** ./expected/stats.out	Sat Jul 23 17:18:20 2005
> --- ./results/stats.out	Sat Jul 23 18:55:17 2005
> ***************
> *** 53,59 ****
>    WHERE st.relname='tenk2' AND cl.relname='tenk2';
>    ?column? | ?column? | ?column? | ?column?
>   ----------+----------+----------+----------
> !  t        | t        | t        | t
>   (1 row)
> 
>   SELECT st.heap_blks_read + st.heap_blks_hit >= pr.heap_blks + cl.relpages,
> --- 53,59 ----
>    WHERE st.relname='tenk2' AND cl.relname='tenk2';
>    ?column? | ?column? | ?column? | ?column?
>   ----------+----------+----------+----------
> !  f        | f        | t        | t
>   (1 row)
> 
>   SELECT st.heap_blks_read + st.heap_blks_hit >= pr.heap_blks + cl.relpages,
> ***************
> *** 62,68 ****
>    WHERE st.relname='tenk2' AND cl.relname='tenk2';
>    ?column? | ?column?
>   ----------+----------
> !  t        | t
>   (1 row)
> 
>   -- End of Stats Test
> --- 62,68 ----
>    WHERE st.relname='tenk2' AND cl.relname='tenk2';
>    ?column? | ?column?
>   ----------+----------
> !  f        | t
>   (1 row)
> 
>   -- End of Stats Test
> 
> ======================================================================
> 
> On Sat, 23 Jul 2005, Bruce Momjian wrote:
> 
> > Date: Sat, 23 Jul 2005 11:36:43 -0400 (EDT)
> > From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
> > To: ohp(at)pyrenet(dot)fr
> > Cc: Rocco Altier <RoccoA(at)Routescape(dot)com>,
> >      Michael Glaesemann <grzm(at)myrealbox(dot)com>, pgsql-patches(at)postgresql(dot)org,
> >      pgsql-hackers(at)postgresql(dot)org
> > Subject: Re: [HACKERS] regressin failure on latest CVS
> >
> > ohp(at)pyrenet(dot)fr wrote:
> > > I just checked latest CVS (5 mn ago) the problem is still the same,
> > > BTW, this is on Unixware 714 and no --enable-integer-datetime
> >
> > Do you have the latest patch included int that version of CVS?
> > Anonymous CVS has a delay, and what was the problem you were seeing, the
> > rounding or the day - 1 result?
> >
> > ---------------------------------------------------------------------------
> >
> >
> > >
> > > Regards
> > > On Sat, 23 Jul 2005, Rocco Altier wrote:
> > >
> > > > Date: Sat, 23 Jul 2005 11:15:44 -0400
> > > > From: Rocco Altier <RoccoA(at)Routescape(dot)com>
> > > > To: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
> > > > Cc: Michael Glaesemann <grzm(at)myrealbox(dot)com>, pgsql-patches(at)postgresql(dot)org,
> > > >      pgsql-hackers(at)postgresql(dot)org, ohp(at)pyrenet(dot)fr
> > > > Subject: RE: [HACKERS] regressin failure on latest CVS
> > > >
> > > > This still does not fix the problem.
> > > >
> > > > I had done my patch to try to mimic the way 8.0 had handled the math
> > > > with the remainders, but to carry it over another bucket (day).
> > > >
> > > > The problem that I see is that we are taking day_remainder and
> > > > multiplying by USECS_PER_DAY.  Which is a double * int64, thus there is
> > > > the precision loss there.
> > > >
> > > > I think initial division by the factor can't be helped, but repeatedly
> > > > doing more floating point math on with it is causing the rounding error.
> > > >
> > > > Thanks,
> > > > 	-rocco
> > > >
> > > > > -----Original Message-----
> > > > > From: Bruce Momjian [mailto:pgman(at)candle(dot)pha(dot)pa(dot)us]
> > > > > Sent: Saturday, July 23, 2005 10:54 AM
> > > > > To: Rocco Altier
> > > > > Cc: Michael Glaesemann; pgsql-patches(at)postgresql(dot)org;
> > > > > pgsql-hackers(at)postgresql(dot)org; ohp(at)pyrenet(dot)fr
> > > > > Subject: Re: [HACKERS] regressin failure on latest CVS
> > > > >
> > > > >
> > > > > Rocco Altier wrote:
> > > > > > This patch fixes the interval regression on my AIX box
> > > > > (kookaburra) by
> > > > > > only doing integer math on the interval, instead of
> > > > > float/double math.
> > > > > >
> > > > > > I think this is the correct way to handle this, since it's
> > > > > an integer
> > > > > > data type.
> > > > > >
> > > > > > I don't know if it will fix Olivier's problem, since I
> > > > > wasn't able to
> > > > > > reproduce it.
> > > > > >
> > > > >
> > > > > I have changed the way I compute the remainder values --- instead of
> > > > > using multiplication, I use division and then subtraction.
> > > > > This should
> > > > > fix your rounding problem.  Looking at your fix, I don't see
> > > > > how adding
> > > > > USECS changes things because the factor is already a float,
> > > > > but I think
> > > > > the problem was more the way I was computing the remainders.
> > > > >
> > > > > Patch attached --- let me know if it does not fix your problem.
> > > > >
> > > > > --------------------------------------------------------------
> > > >
> > > >
> > > >
> > >
> > > --
> > > Olivier PRENANT        	        Tel: +33-5-61-50-97-00 (Work)
> > > 15, Chemin des Monges                +33-5-61-50-97-01 (Fax)
> > > 31190 AUTERIVE                       +33-6-07-63-80-64 (GSM)
> > > FRANCE                          Email: ohp(at)pyrenet(dot)fr
> > > ------------------------------------------------------------------------------
> > > Make your life a dream, make your dream a reality. (St Exupery)
> > >
> > > ---------------------------(end of broadcast)---------------------------
> > > TIP 6: explain analyze is your friend
> > >
> >
> >
> 
> -- 
> Olivier PRENANT        	        Tel: +33-5-61-50-97-00 (Work)
> 15, Chemin des Monges                +33-5-61-50-97-01 (Fax)
> 31190 AUTERIVE                       +33-6-07-63-80-64 (GSM)
> FRANCE                          Email: ohp(at)pyrenet(dot)fr
> ------------------------------------------------------------------------------
> Make your life a dream, make your dream a reality. (St Exupery)
> 

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

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