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From ChatPristi
Subject Re: Slow performance with 9.3-110x JDBC 4
Date
Msg-id 1396002343.73991.YahooMailNeo@web28905.mail.ir2.yahoo.com
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In response to Re: Slow performance with 9.3-110x JDBC 4  (Lachezar Dobrev <l.dobrev@gmail.com>)
Responses Re: Slow performance with 9.3-110x JDBC 4  (Dave Cramer <pg@fastcrypt.com>)
Re: Slow performance with 9.3-110x JDBC 4  (ChatPristi <cchristo_0899@yahoo.fr>)
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Thank you very much for your help and explanations.

Indeed, the Lachezar's recommendation  ( jdbc:postgresql://localhost/database?protocolVersion=2) restores the speed: 190413 ms with jdbc-9.3.1101 and postgresql 9.3.4.

As I used bytea and due to change since postgresql 9.0 for handling them (bytea_output parameter), my programs only work with  jdbc-9.3.1101 (and no longer with jdbc-8.4-703).

So, I must use 9.3.1101. However, what  does the sentence "I was recommending that for testing purposes only" by Lachezar means ? How to increase performance of server side prepared statements ?



Le Vendredi 28 mars 2014 10h50, Lachezar Dobrev <l.dobrev@gmail.com> a écrit :
  For the record: I was recommending that for testing purposes only, to check if the reduced performance is related to protocol version (I believe there is a significant change it might).


2014-03-27 21:52 GMT+02:00 Dave Cramer <davecramer@gmail.com>:
I wanted to avoid that recommendation, but since it is out there. protocolVersion reverts to the same protocol as 8.4 uses which does not use server side prepared statements

And I would expect it to speed up, or at least be the same as 8.4.7

Dave



On Thu, Mar 27, 2014 at 1:45 PM, Edson Richter <edsonrichter@hotmail.com> wrote:
Em 27/03/2014 13:58, Lachezar Dobrev escreveu:
  You might want to do the same tests after adding ?protocolVersion=2
to the connection URL. i.e.:  jdbc:postgresql://localhost/database?protocolVersion=2

2014-03-27 15:35 GMT+02:00 ChatPristi <cchristo_0899@yahoo.fr>:

Dear All,

I have a java program that does bulk insertions (with transactions and
PreparedStatements) in a postgresql database. I have a performance divided
between two and four when using 9.3-1100 JDBC4 and 9.3-1101 in comparison
with postgresql-8.4-703 JDBC4 independently of postgresql version.
Time(ms)                PG     8.4.7            9.3.4
Driver
8.4-703                          193390         188379
9.3.1101                         349404         344344

Does anybody else saw such a difference ? What reasons can explain it ?

Another point, is that the bulk insertions are prerformed by parallel
processes and 9.3-110x JDBC4 drivers appear to scale poorly.

Thanks for any help.

 What to expect from "protocolVersoin=2"?
 Speed up or down?

 Edson

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