Re: ORA-00018 issues

From: Paul Drake <>
Date: Thu, 26 Feb 2009 15:20:19 -0500
Message-ID: <>

On Thu, Feb 26, 2009 at 1:25 PM, Maureen English <>wrote:

> We're experiencing a very strange problem...ORA-00018 errors.
> Yes, I know that the error means 'maximum number of sessions exceeded',
> but that is not the case.
> We are running Oracle on Solaris 10. We have a consultant
> who is working in this database, using a connection string like:
> jdbc:cp:uPortalPooled;driver=oracle.jdbc.driver.OracleDriver;
> ;1234:MYDB
> where is the machine and MYDB is the database SID.
> We're trying to figure out if his attempts to connect are messing things
> up, or if there is something else going on.
> If we reboot the machine, the problem disappears -- we can connect via
> sqlnet.
> Then the consultant tries his connection, gets the error and we can no
> longer
> connect via sqlnet.
> Any suggestions for further troubleshooting? We're looking into java
> issues,
> as well as system/database issues, but so far nothing is obvious.
> - Maureen
> --


If I had to guess ... my guess would be "ZOMBIES". They are known to appear from time to time when app servers are used, particularly in "not the most recent patchset" environments.

SQL> select count(1) from v$process where addr>'00';

During the next time that the error condition is being experienced, give that query a try.
A system state dump might show what is going on as well. As long as you're taking one, you might as well get several a minute or so apart.

The "sessions" may have been cleaned up without actually freeing the process slot.

I haven't worked on Solaris, but I have seen more than my share of these on you know where prior to deploying the patchset.



Received on Thu Feb 26 2009 - 14:20:19 CST

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