Groups > comp.lang.java.programmer > #32991

Re: Performance JPA

From	Arne Vajhøj <arne@vajhoej.dk>
Newsgroups	comp.lang.java.programmer
Subject	Re: Performance JPA
Date	2015-11-03 20:44 -0500
Organization	Aioe.org NNTP Server
Message-ID	<n1bnte$2j8$2@speranza.aioe.org> (permalink)
References	<87lhagkcsh.fsf@Equus.decebal.nl> <563763d9$0$23727$e4fe514c@news.xs4all.nl> <87d1vrk20x.fsf@Equus.decebal.nl> <56389a9e$0$23778$e4fe514c@news.xs4all.nl>

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On 11/3/2015 6:29 AM, Silvio wrote:
> On 11/03/2015 07:52 AM, Cecil Westerhof wrote:
>> As I understood it until now, there should be a little overhead, but
>> it can be worse I understand now. As said in the above rowmapper was
>> used. Now the application uses em.find to read. For displaying a page
>> only reads are done, so using em.find instead rs.get... seems to make
>> a very big difference. Is there a reason for this and can there be
>> something done about this?

> If you look at the executed SQL you will probably see a huge amount of
> lookup-by-pk statements executed where in the past these where
> relatively rare since they where mostly multi-row selects (usually
> foreign key conditions possibly combined with other filters).
>
> This is typical for an application that has undergone a naive (in the
> one-to-one sense) port to an ORM layer.

Really??

I have never seen such a problem.

em.createQuery is easy and generate an equivalent SQL to the one
to chose if manually written.

Arne

Thread

Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-02 09:47 +0100
  Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-02 14:23 +0100
    Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-03 07:52 +0100
      Re: Performance JPA Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-03 11:16 +0000
        Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-03 19:11 +0100
          Re: Performance JPA Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-03 19:15 +0000
            Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-04 09:28 +0100
              Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-10 08:07 +0100
                Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-10 10:35 +0100
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-11 06:20 +0100
                Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-11 09:32 -0500
                Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-10 19:56 -0500
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-11 06:50 +0100
                Re: Performance JPA Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-11 12:17 +0000
                Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-11 09:30 -0500
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-11 23:20 +0100
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-11 23:11 +0100
                Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-11 19:10 -0500
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-12 07:27 +0100
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-13 08:30 +0100
                Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-13 10:45 +0100
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-13 11:06 +0100
                Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-13 13:36 +0100
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-20 09:04 +0100
                Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-13 21:46 -0500
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-20 09:09 +0100
          Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-03 20:35 -0500
            Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-04 09:35 +0100
              Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-07 22:09 -0500
      Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-03 12:29 +0100
        Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-03 19:23 +0100
        Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-03 20:44 -0500
          Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-04 09:48 +0100
          Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-04 10:23 +0100
            Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-04 11:27 +0100
              Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-04 12:42 +0100
                Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-07 22:18 -0500
                Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-09 10:43 +0100
                Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-20 09:13 +0100
            Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-07 22:12 -0500
              Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-09 10:22 +0100
                Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-10 21:35 -0500
                Re: Performance JPA Silvio <silvio@internet.com> - 2015-11-11 11:29 +0100
      Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-03 20:42 -0500
        Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-04 11:19 +0100
          Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-07 22:05 -0500
  Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-02 20:08 -0500
    Re: Performance JPA Cecil Westerhof <Cecil@decebal.nl> - 2015-11-03 07:55 +0100
      Re: Performance JPA Arne Vajhøj <arne@vajhoej.dk> - 2015-11-03 20:45 -0500
  Re: Performance JPA Lew <lewbloch@gmail.com> - 2015-11-16 14:43 -0800

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