Intermittent JDBC connection

[teser3]

I am connecting to Oracle 10g RAC using JDBC in Tomcat 6.0.20.
It works around 50% of the time. When it doesnt work it shows this
error message:
IO exception: The Network Adapter could not establish the connection.

Here is my JDBC String:
jdbcracle:thin(DESCRIPTION=(LOAD_BALANCE=on)
(ADDRESS=(PROTOCOL=TCP)
(HOST=170.11.5.111) (PORT=1521)) (ADDRESS=(PROTOCOL=TCP)
(HOST=170.11.5.112)
(PORT=1521)) (CONNECT_DATA=(SERVICE_NAME=service) (FAILOVER_MODE
=
(TYPE = SELECT) (METHOD = BASIC) (RETRIES = 180) (DELAY =
5) )))


The above Description parameters I use in my tnsnames.ora and can
successfully connect to the Oracle RAC using SQL Plus with no issues.
I can also successfully ping to the IP addresses with no issues.

I also played around with the JDBC string and added (FAILOVER=ON) but
still have same issues.

Please advise.

 

[Mike Schilling]

I am connecting to Oracle 10g RAC using JDBC in Tomcat 6.0.20.
It works around 50% of the time. When it doesnt work it shows this
error message:
IO exception: The Network Adapter could not establish the connection.

Here is my JDBC String:
jdbcracle:thin(DESCRIPTION=(LOAD_BALANCE=on)
(ADDRESS=(PROTOCOL=TCP)
(HOST=170.11.5.111) (PORT=1521)) (ADDRESS=(PROTOCOL=TCP)
(HOST=170.11.5.112)
(PORT=1521)) (CONNECT_DATA=(SERVICE_NAME=service) (FAILOVER_MODE
=
(TYPE = SELECT) (METHOD = BASIC) (RETRIES = 180) (DELAY =
5) )))


The above Description parameters I use in my tnsnames.ora and can
successfully connect to the Oracle RAC using SQL Plus with no issues.
I can also successfully ping to the IP addresses with no issues.

I also played around with the JDBC string and added (FAILOVER=ON) but
still have same issues.

Please advise.

You're connecting to one of two ports, and it works 50% of the time. What
happens if you connect to only one of the ports?

 

[Tom Anderson]

You're connecting to one of two ports, and it works 50% of the time.
What happens if you connect to only one of the ports?

By 'port' do you mean 'address'?

I'd get in touch with your network administrator, and also your DBA. It's
unlikely to be anything in the java, since it does work some of the time,
so there's not a lot you can do to debug this on your own.

It could be the DB hitting a connection limit and refusing connections;
i've had that happen, although with Oracle 11 the error you get is
'java.sql.SQLException: Io exception: Got minus one from a read call',
which is not what you get. This looks more like a problem i had recently
where the local DNS server was on the fritz, and some connections to
databases would randomly hang and then fail. So, note the time when this
problem occurred, and ask the DBA to check the Oracle logs for anything
weird happening at that time, and ask the network admin to check his logs
similarly, and to have a quick check for anything which could be causing
this problem.

tom

 

[Mike Schilling]

By 'port' do you mean 'address'?

Two TCP ports: Both 1521 on 170.11.5.111 and 1521 on 170.11.5.112. I'm
wondering if only one of themn is answering.

 

[Tom Anderson]

Two TCP ports: Both 1521 on 170.11.5.111 and 1521 on 170.11.5.112.

Oh, i see, you're using the word 'port' in the way it's defined in the
specifications. How unusual .

I'm wondering if only one of themn is answering.

Definitely something to check.

tom