Re: Statistical aggregate functions are not working with PARTIALaggregation

At Wed, 08 May 2019 13:06:36 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote in
<20190508.130636.184826233.horiguchi.kyotaro@lab.ntt.co.jp>
> At Tue, 07 May 2019 20:47:28 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote
in<20190507.204728.233299873.horiguchi.kyotaro@lab.ntt.co.jp>
 
> > Hello.
> > 
> > At Tue, 7 May 2019 14:39:55 +0530, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com> wrote in
<CAKcux6=YBMCntcafSs_22dS1ab6mGay_QUaHx-nvg+_FVPMg3Q@mail.gmail.com>
> > > Hi,
> > > As this issue is reproducible without partition-wise aggregate also,
> > > changing email subject from "Statistical aggregate functions are not
> > > working with partitionwise aggregate " to "Statistical aggregate functions
> > > are not working with PARTIAL aggregation".
> > > 
> > > original reported test case and discussion can be found at below link.
> > >
https://www.postgresql.org/message-id/flat/CAKcux6%3DuZEyWyLw0N7HtR9OBc-sWEFeByEZC7t-KDf15FKxVew%40mail.gmail.com
> > 
> > The immediate reason for the behavior seems that
> > EEOP_AGG_STRICT_INPUT_CHECK_ARGS considers non existent second
> > argument as null, which is out of arguments list in
> > trans_fcinfo->args[].
> > 
> > The invalid deserialfn_oid case in ExecBuildAggTrans, it
> > initializes args[1] using the second argument of the functoin
> > (int8pl() in the case) so the correct numTransInputs here is 1,
> > not 2.
> > 
> > I don't understand this fully but at least the attached patch
> > makes the test case work correctly and this seems to be the only
> > case of this issue.
> 
> This behavior is introduced by 69c3936a14 (in v11).  At that time
> FunctionCallInfoData is pallioc0'ed and has fixed length members
> arg[6] and argnull[7]. So nulls[1] is always false even if nargs
> = 1 so the issue had not been revealed.
> 
> After introducing a9c35cf85c (in v12) the same check is done on
> FunctionCallInfoData that has NullableDatum args[] of required
> number of elements. In that case args[1] is out of palloc'ed
> memory so this issue has been revealed.
> 
> In a second look, I seems to me that the right thing to do here
> is setting numInputs instaed of numArguments to numTransInputs in
> combining step.

By the way, as mentioned above, this issue exists since 11 but
harms at 12. Is this an open item, or older bug?

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center