oracle listner problem

Posted on 2004-09-01
Last Modified: 2008-01-09
I have oracle 10g server running on redhat linux 9.0, the problem is that the when trying to connect from the clients its giving the error "ORA-12516: TNS:listener could not find instance with   matching protocol stack.". After restarting the db its works fine. Again the same problem happens after some time. What could be the problem. Please give me a solution for this

thanks in advance

Question by:shajumc
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2

Expert Comment

ID: 11960962
How is your Server configured? Is it shared or dedicated?

Expert Comment

ID: 11961000
copied from Oracle Metalink

Client connections may intermittently fail with either of the following errors:

TNS-12516 TNS:listener could not find instance with matching protocol stack
TNS-12519 TNS:no appropriate service handler found

Additionally, a TNS-12520 error may appear in the listener log.

TNS:listener could not find available handler for requested type of server

The output of the lsnrctl services command may show that the service handler
is in a "blocked" state.
e.g. '"DEDICATED" established:1 refused:0 state:blocked'


None necessarily.  Perhaps increase in load.

By way of instance registration, PMON is responsible for updating the listener
with information about a particular instance such as load and dispatcher
information.  Maximum load for dedicated connections is determined by the
PROCESSES parameter.  The frequency at which PMON provides SERVICE_UPDATE
information varies according to the workload of the instance.  The maximum
interval between these service updates is 10 minutes.  

The listener counts the number of connections it has established to the instance
but does not immediately get information about connections that have terminated.  
Only when PMON updates the listener via SERVICE_UPDATE is the listener
informed of current load.  Since this can take as long as 10 minutes, there can be
a difference between the current instance load according to the listener
and the actual instance load.  

When the listener believes the current number of connections has reached maximum
load, it may set the state of the service handler for an instance to "blocked"
and begin refusing incoming client connections with either of the following

TNS-12516 TNS:listener could not find instance with matching protocol stack
TNS-12519 TNS:no appropriate service handler found

Additionally, a TNS-12520 error may appear in the listener log.

The output of lsnrctl service may show that the service handler is "blocked".
e.g. '"DEDICATED" established:1 refused:0 state:blocked'


Increase the value for PROCESSES.
LVL 48

Accepted Solution

schwertner earned 125 total points
ID: 11961106
This is a bug in 10g and will be fixed in next releases. I experience the same problem with 10g on Windows/2000.
The problem arises when we shutdown the instance and after that bounce it.  In this case we have to restart the box - fun!

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Sybase and replication server 13 82
Read XML values 8 69
oracle sql developer + get hour from datetime field 2 26
ORACLE SQL DEVELOPER + Compare Tables 5 37
This article started out as an Experts-Exchange question, which then grew into a quick tip to go along with an IOUG presentation for the Collaborate confernce and then later grew again into a full blown article with expanded functionality and legacy…
Working with Network Access Control Lists in Oracle 11g (part 1) Part 2: So, you upgraded to a shiny new 11g database and all of a sudden every program that used UTL_MAIL, UTL_SMTP, UTL_TCP, UTL_HTTP or any oth…
This video explains at a high level about the four available data types in Oracle and how dates can be manipulated by the user to get data into and out of the database.
This videos aims to give the viewer a basic demonstration of how a user can query current session information by using the SYS_CONTEXT function

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question