Re: Intermittent Postgres Connection refused Errors (JDBC)

"Aaron Bono" <postgresql@xxxxxxxxxx> · Tue, 1 May 2007 17:34:37 -0500

On 5/1/07, Srinivas Kotapally <ksrinivas@xxxxxxxxxxxx> wrote:

Thanks for the response.  No, I am not exceeding the 
max limit.  I tried a test which would exceed the max connections (which is 
100 - set in postgresql.conf).  The error at that point is 

org.postgresql.util.PSQLException: FATAL: sorry, too many 
clients already

Are any errors showing up in the PostgreSQL logs?

Also, are do you have any of your already established connections in your pool being that are begin disconnected?  If so, you may be having intermittent network problems.

The error you are getting implies that you are having connectivity problems between servers.  I am tomcat and PostgreSQL are running on separate machines.  Have you tried replicating this problem by running tomcat and PostgreSQL on the same machine and connecting to localhost?

From: aaron.bono@xxxxxxxxx 
[mailto:aaron.bono@xxxxxxxxx] On Behalf Of Aaron Bono
Sent: 
Tuesday, May 01, 2007 5:59 PM
To: ksrinivas@xxxxxxxxxxxx
Cc: 
pgsql-admin@xxxxxxxxxxxxxx
Subject: Re: [ADMIN] Intermittent Postgres 
Connection refused Errors (JDBC)

On 5/1/07, Srinivas Kotapally <ksrinivas@xxxxxxxxx> wrote:

  Hi

  I am managing an application that uses the 
  Postgres backend.  Of late we have started getting connection refused 
  errors every now and then.  We have not been able to identify the cause 
  of this.  Any hints or known bugs that I should be aware of?  Thanks 
  for any help extended!

  Regards

Srinivas

  Here is the environment I work 
  in:
Application is a Java app residing on a web server and is running on 
  Tomcat.  
  Versions:
  jdk: 1.5.0_02
  Tomcat 5.5.23
  Web server: 
  httpd-2.0.52-28.ent.centos4
  Kernel: Linux version 2.6.9-42.0.10.ELsmp 
  (mockbuild@xxxxxxxxxxxxxxxxxxx ) (gcc version 3.4.6
 20060404 
  (Red Hat 3.4.6-3)) #1 SMP Tue Feb 27 09:40:21 EST 2007
Postgres: 8.1.8 (64 
  bit version) - 
  postgresql-libs-8.1.8-1PGDG
postgresql-8.1.8-1PGDG
postgresql-server-8.1.8-1PGDG
postgresql-contrib-8.1.8-1PGDG

  We use the JDBC2 driver that comes with 
  Postgres.

  The specific error we get 
  is:

  CDBConnectionPool.newConnection() : 
  SQLException= org.postgresql.util.PSQLException: Connection refused. Check 
  that the hostname and port are correct and that the postmaster is accepting 
  TCP/IP connections.

Are 
you exceeding the maximum allowed connections in PostgreSQL?  I would start 
by checking the PostgreSQL logs.  If nothing shows up, it may be a network 
or application configuration issue.

-Aaron 

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