Re: is possible cache tupledesc templates in execution plan? significant performance issue, maybe bug?

2017-10-08 19:10 GMT+02:00 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:

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> 2017-10-08 19:04 GMT+02:00 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
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>> 2017-10-08 18:59 GMT+02:00 Andres Freund <andres(at)anarazel(dot)de>:
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>>> On 2017-10-08 18:57:28 +0200, Pavel Stehule wrote:
>>> > 2017-10-08 18:44 GMT+02:00 Andres Freund <andres(at)anarazel(dot)de>:
>>> >
>>> > > Hi,
>>> > >
>>> > > On 2017-10-08 18:36:23 +0200, Pavel Stehule wrote:
>>> > > > 2. Lot of used tables are pretty wide - 60, 120, .. columns
>>> > > >
>>> > > > Now, I am doing profiling, and I see so most time is related to
>>> > > >
>>> > > > ExecTypeFromTLInternal(List *targetList, bool hasoid, bool
>>> skipjunk)
>>> > >
>>> > > Yea, that's known - I've complained about this a couple times. You
>>> could
>>> > > try whether the following master branch helps:
>>> > > https://git.postgresql.org/gitweb/?p=users/andresfreund/
>>> > > postgres.git;a=shortlog;h=refs/heads/simple_statement_perf
>>> > >
>>> > > That's just micro-optimization though, not a more fundamental
>>> > > solution. But for me it yields pretty nice speedups for cases with
>>> long
>>> > > tlists.
>>> > >
>>> > >
>>> > it is just this patch
>>> >
>>> > HeapTuple tup;
>>> > Form_pg_type typTup;
>>> >
>>> > + if (typid < FirstBootstrapObjectId)
>>> > + break;
>>> > +
>>> > tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
>>> > if (!HeapTupleIsValid(tup))
>>> > elog(ERROR, "cache lookup failed for type %u", typid);
>>>
>>> No.
>>>
>>
>> please, how I can clone your repo?
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>>
>> I found it
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With your branch the execution is about 15-20% faster - so overhead of
exec init is more significant.

Unfortunately Oracle is significantly faster for this pattern

Regards

Pavel