Re: Severe performance degradation when using the 9.2-1000 JDBC 4 driver

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От Mikko Tiihonen
Тема Re: Severe performance degradation when using the 9.2-1000 JDBC 4 driver
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Msg-id 51061EFB789B4A45AC6598C83649B7BE8DB56604@NBL-EXCD1-01.nebula.local
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Ответ на Re: Severe performance degradation when using the 9.2-1000 JDBC 4 driver  (Craig Ringer <ringerc@ringerc.id.au>)
Ответы Re: Severe performance degradation when using the 9.2-1000 JDBC 4 driver  (Dave Cramer <pg@fastcrypt.com>)
Re: Severe performance degradation when using the 9.2-1000 JDBC 4 driver  (Craig Ringer <ringerc@ringerc.id.au>)
Re: Severe performance degradation when using the 9.2-1000 JDBC 4 driver  (Sérgio Saquetim <sergiosaquetim@gmail.com>)
Re: Severe performance degradation when using the 9.2-1000 JDBC 4 driver  (Kris Jurka <books@ejurka.com>)
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I think the DNS lookup is part of the JDBC failover connection patch that I created.
I initially used a InetSocketAddress.getHostString() that does not do any DNS lookups, but since that method was added
inJava7 I had to revert to getHostName() method which does. 

I see following options:
1) modify the code so that is uses reflection and if Java7 is detected it will use the no-lookup method
2) wait 4 months until Oracle drops Java6 support (Java6 was supposed to be EOL already few months back) and use the
no-lookupvariant 
3) let the code stay as is and let users fix their dns servers

-Mikko
________________________________________
From: pgsql-jdbc-owner@postgresql.org [pgsql-jdbc-owner@postgresql.org] on behalf of Craig Ringer
[ringerc@ringerc.id.au]
Sent: 18 October 2012 12:03
To: Sérgio Saquetim
Cc: pgsql-jdbc@postgresql.org; Rafael dos Santos Silva
Subject: Re: [JDBC] Severe performance degradation when using the 9.2-1000 JDBC 4 driver

On 10/18/2012 12:16 PM, Sérgio Saquetim wrote:
> I can confirm the problem, it's taking about 4000ms to get a Connection.

That sounds like a broken DNS or reverse DNS setup in your environment,
it's about right for your average DNS timeout.

--
Craig Ringer


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