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    Why are there 4 Oracle listeners running (v4)?

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    • Article Type: General
    • Product: MetaLib
    • Product Version: 4

    Description:
    I get the following description when starting the listener:

    STATUS of the LISTENER
    ------------------------
    Alias LISTENER
    Version TNSLSNR for Linux: Version 10.2.0.3.0 - Production
    Start Date 29-MAY-2007 13:59:26
    Uptime 0 days 0 hr. 0 min. 33 sec
    Trace Level off
    Security ON: Local OS Authentication
    SNMP ON
    Listener Parameter File /exlibris/app/oracle/product/102/network/admin/listener.ora
    Listener Log File /exlibris/app/oracle/product/102/network/log/listener.log
    Listening Endpoints Summary...
    (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=meta4)))
    (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=castor.oit.umn.edu)(PORT=1521)))
    Services Summary...
    Service "meta3.oit.umn.edu" has 1 instance(s).
    Instance "meta3", status READY, has 9 handler(s) for this service...
    Service "meta4" has 1 instance(s).
    Instance "meta4", status UNKNOWN, has 1 handler(s) for this service...
    Service "meta4.castor.oit.umn.edu" has 1 instance(s).
    Instance "meta4", status READY, has 9 handler(s) for this service...
    Service "meta4XDB.castor.oit.umn.edu" has 1 instance(s).
    Instance "meta4", status READY, has 1 handler(s) for this service...
    Service "meta4_XPT.castor.oit.umn.edu" has 1 instance(s).
    Instance "meta4", status READY, has 9 handler(s) for this service...
    The command completed successfully

    The output of util O-2-3 is as follows:
    --------
    4317 ? S 0:00 /exlibris/app/oracle/product/102/bin/tnslsnr LISTENER -inherit
    4318 ? S 0:00 /exlibris/app/oracle/product/102/bin/tnslsnr LISTENER -inherit
    4319 ? S 0:00 /exlibris/app/oracle/product/102/bin/tnslsnr LISTENER -inherit
    4320 ? S 0:00 /exlibris/app/oracle/product/102/bin/tnslsnr LISTENER -inherit

    I don't think we need 4 listeners, nor the old Metalib 3 listener.
    What exactly are all these extra listeners doing?
    Not sure what configuration file they were pulled from.
    More than one entry is probably alright, but what causes the difference?
    The listener is running fine but we're curious about the multiple entries.

    Resolution:
    When there is more than one database on the machine, then there will be:

    A listener for each database for IPC communication
    A listener for all databases for TCP communication for each MetaLib version (e.g., ML 3.13 vs. ML 4.0x).

    You can see how many databases are running using command:
    > ps –ef | grep smon

    Since there are 2 installations on the server, each one of a different MetaLib version it makes sense there are 4 listener processes on the server.


    The multiple processes are because each ML version requires two listener processes, one for IPC communication and the other for TCP communication.

    Therefore, the four processes on your server are for the ML3.13 and ML4 installations.

    FYI - if you need to restart the Oracle listener, do the following:

    >>dlib dat01
    >>util o
    >>2 (Oracle Listener)
    >>1 (Activate Oracle Listener)
    >>Enter oracle10’s password

    • Article last edited: 10/8/2013