I got following exceptions.

-----------------------

Exception-1

raise exc.DBAPIError.instance(None, None, e)
DatabaseError: (DatabaseError) ORA-12519: TNS:no appropriate service
handler found
None None

Solution i found in the net:

1. Run SQL*Plus and login
2. Run the command “alter system set processes=150
scope=spfile;” in the SQL*Plus
3. Restart the database.

Question:
Is the correct way to solve this problem?

-----------------------

Exception -2

QueuePool limit of size 10 overflow 10 reached, connection timed out,
timeout 30
Traceback (most recent call last):
raise exc.TimeoutError("QueuePool limit of size %d overflow %d
reached, connection timed out, timeout %d" % (self.size(),
self.overflow(), self._timeout))
TimeoutError: QueuePool limit of size 10 overflow 10 reached,
connection timed out, timeout 30

Question:
How can i find the Pool size to be used?

On Aug 16, 8:42*am, sajuptpm <sajup... (AT) gmail (DOT) com> wrote:
Based on the Oracle error message information the posted solution does
would only be useful if the reason the listener was backed up and
being flooded with commands was if the reason for the backup was that
the Oracle database parameter value for processes was being exceeded
and your license allowed you to have more connections to the database
than the value processes was set to. This could be a side effect from
Network issues, OS process limit issues, or database issues. The fix
would depend on the root cause of the listener not being able to hand
off connections.

$ oerr ora 12519
12519, 00000, "TNS:no appropriate service handler found"
// *Cause: The listener could not find any available service handlers
that
// are appropriate for the client connection.
// *Action: Run "lsnrctl services" to ensure that the instance(s) have
// registered with the listener, and are accepting connections.


By any chance did this error happen while there was some type of error
occurring on the database? Or right after a database restart? What
does the alert log for the target database show?

HTH -- Mark D Powell --

Database is working and can perform database operaions.
This error occuring only when I trying to run my web application.
My application using thread and trying to update some tables
simultaneously( thread interval is 1 second ).I does not showing any
deadlock error.

how can i find optimal Queue pool size?

sajup:

Try the relevant performance tuning guide for your release ... all the
Oracle documentation is free.

One url is http://tahiti.oracle.com

On Aug 16, 10:18*am, sajuptpm <sajup... (AT) gmail (DOT) com> wrote:
Well if the database is otherwise available and working fine then as
the problem only affects your applicaiton you need to look at how you
are attempting to connect to the database. I am not a coder but you
should consider posting your connect information so that maybe someone
will stop the issue. Comparing your connection to example connection
information in the manuals might help.

Good luck
-- Mark D Powell --

On Aug 16, 10:24*am, John Hurley <hurleyjo... (AT) yahoo (DOT) com> wrote:
John, actually I think this is the sqlnet queue so try this
LISTENER=
(DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=1521)
(QUEUESIZE=20)))

The default queue varies by platform such as Solaris is only 5 while
Windows NT is 50.


Ref: Oracle® Database Net Services Administrator's Guide 10g Release 2
(10.2) Part Number B14212-02 Ch 10. Configuring and Administering the
Listener

HTH -- Mark D Powell --