My apologize, my previous test was wrong. It was old jars. So the time is still improved but remain less than with jdbc-8.4: 223528 ms (jdbc-9.3) vs 190413 ms ( jdbc-8.4) .
Le Vendredi 28 mars 2014 11h26, ChatPristi <cchristo_0899@yahoo.fr> a écrit :
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).
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
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
--
Edson Carlos Ericksson Richter Sistemas para Bibliotecas, Escolinhas Infantis Projetos sob medida para sua empresa
