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Thread: ORA-12571 TNS: packet writer failure

  1. #1
    Join Date
    Aug 2000
    Chicago IL
    I am getting this error message on my 8.06 NT database.
    The sqlnet is upto date. I cant exactly pinpoint what to look for. Any ideas?

  2. #2
    Join Date
    May 2000
    Turn on Trace and go through the trace file. You may find collision problem in the trace file.

  3. #3
    Join Date
    Mar 2000
    This occurs when there is a problem in the network as well,but ideal checking by enable the trace.

  4. #4
    Join Date
    Aug 2000
    Chicago IL
    how do we turn tracing on in Oracle?

  5. #5
    Join Date
    Oct 2000
    Saskatoon, SK, Canada
    Check this oracle's article for details7.1 Introduction
    For most problems you need to identify the relevant parts of a
    connection to trace. To do this consider which scenario you are
    having problems with and where tracing needs to be enabled.
    Note that tracing produces a lot of output , especially at higher
    trace levels.

    There are 3 main areas of Net that can produce trace output:
    1 = the SQL*Net 'client'
    2 = the 'listener' process
    3 = the SQL*Net 'server'.

    a) Establishing a connection:

    Client ----> Listener ----> Server
    ^ ^ ^
    1 2 3

    b) An established connection:

    Client --------> Server
    ^ ^
    1 3

    c) Opening a database link:

    Client ----> Server ----> Listener -----> Server2
    ^ ^ ^ ^ ^
    1 3 * 2 3

    * Note here that the Oracle server process is also a SQL*Net
    client when it makes an outgoing call to a listener to
    open a database link. Database links are OPENED when first
    used. They should then remain open until closed.
    It is the 'server' trace which traces the outbound DBLINK

    d) An established database link:

    Client ----> Server -----> Server2
    ^ ^ ^ ^
    1 3 * 3

    In each case here there are several potential sampling points. You
    should be able to identify quickly which of these scenarios matches
    your setup. As these scenarios are likely to involve connections
    between different machines you should remember that tracing for any
    process is controlled by the configuration details that the process
    reads WHEN IT IS STARTED. This is especially important when looking
    at MTS connections as the SQL*Net server is the 'dispatcher' process.
    Some dispatchers are started when the database instance is started
    and others may start at a later time (on demand). Each dispatcher will
    read their SQL*Net configuration WHEN THEY START.

    It is also important to note that to trace 'Server' processes started
    by the listener then the 'sqlnet.ora' file used depends on the
    environment passed to the 'Server' by the listener.

    7.2 Client Tracing
    For client TOOLS edit or create the file $HOME/.sqlnet.ora and add
    the lines:
    trace_directory_client=/tmp # Or a known directory
    trace_unique_client=true # Add '_pid' to trace filename

    This will turn on FULL tracing for your user account only producing
    output in a file called /tmp/cli_<PID>.trc .
    (For some SQL*Net versions the file will be just /tmp/cli.trc)

    For client 'ORACLE' process (as in the case of database links) put this
    same information into $TNS_ADMIN/sqlnet.ora file.

    On versions up to and including Oracle 7.0.16 client trace may not
    add a process ID to the name of the trace file. This means two
    processes may end up writing to the same trace file unless you
    take care to control which processes write trace output to each file.

    7.3 Listener Tracing
    Listener tracing can ONLY be configured in the listener.ora file.
    Add the lines below to the listener.ora file:

    trace_directory_listener=/tmp # Or a known directory

    This will define FULL listener tracing to the file /tmp/listener.trc.
    You can enable this tracing by either:

    lsnrctl reload

    lsnrctl stop;
    lsnrctl start;

    It is often useful to confirm that a listener is listening on a
    specified address. Most Unix machines include a command called
    'netstat' (Often in /etc or in /usr/etc). The command netstat -a
    should list all TCP/IP end points on which a listener is listening.

    For a listener listening on HOST=... PORT=1580 there should be a
    netstat entry of the form:

    RecvQ SendQ Local Address Foreign Address TCP state
    0 0 *.1580 *.* LISTEN

    Note: Some versions of netstat will only list established connections
    and not listen end points. See the man page on your machine.

    7.4 Server Tracing
    Server side trace is not required as often as the other two traces
    mainly because most problems are related to establishing a connection.
    Once a connection has been established the client and server processes
    are communicating. It is sometimes useful to see exactly what SQL
    commands have been received by the server, and what data it has sent
    back out.

    The file $TNS_ADMIN/sqlnet.ora controls the server side tracing. Add
    the lines below to this file:

    trace_directory_server=/tmp # Or a known directory

    Output should be sent to the file /tmp/server_<PID>.trc

    Note: Server side tracing acts on the SQL*Net server side.
    For dedicated connections this is the Oracle process on the
    server machine.
    For MTS connections this is the DISPATCHER and NOT the shared
    server. Data is passed between the dispatcher and the shared
    servers via the SGA and this does NOT involve SQL*Net.
    It is also important to note that as a dispatcher handles
    several client processes the dispatcher trace output can be a
    mix of trace from many client processes making it VERY difficult
    to follow. The general advice for such problems is:

    a) See if the problem reproduces WITHOUT using MTS - if
    so the trace is much cleaner

    b) If a problem ONLY reproduces under MTS ensure the machine
    is in a controlled environment so you can be sure that only
    YOUR process is using the dispatcher.

    7.5 Trace Summary

    1) Identify where you need to trace.
    2) Identify which files on which machines control tracing at these
    points. Tracing is controlled in the following files:

    Client Server Listener
    ~~~~~~ ~~~~~~ ~~~~~~~~
    Files: $HOME/.sqlnet.ora sqlnet.ora listener.ora

    3) Add in the relevant trace parameters (See Below)
    4) Restart any processes that need to read the new trace values.
    Reload the listener as required.
    5) Reproduce your problem
    6) Save all your trace output immediately
    7) Disable the tracing

    7.6 Main Trace Parameters

    trace_level_[listener|client|server] = [off|user|admin|0-16]
    trace_file_[listener|client|server] = Filename *1
    trace_directory_[listener|client|server] = Directory *2

    *1 Unquoted (") filenames will be translated into lower case.
    *2 You CANNOT use environment variables in the Filename or Directory

    7.7 Diagnosing Trace output

    Trace output can be very difficult to follow. Before looking at a
    trace file make sure:

    a) You are familiar with the sequence of events in setting up
    a connection. SQL*Net connections follow a sequence of
    events - you will need to determin where in the sequence
    the problem occurs.

    b) Do not be misled by error reports in the trace files. You
    must follow the context of the errors - an error may be
    quite valid at that point in a sequence. Eg: For client
    connections a list of addresses to call is built - if the
    first address yeilds no response the next address is tried.
    This next address may yeild a response and the 'true' error
    occurs at this point in the sequence.

    c) Do not be misled by unusual 'Bequeath' connections in the
    trace. If an error is received over SQL*Net the client
    may use a "Bequeath" operation to spawn an oracle process
    which it then uses to get the TEXT of the error. A very short
    exchange of packets occurs and the bequethed process exits.
    The 'TRUE' problem is likely to be before this bequeath

    Useful trace 'tags':
    The following are useful items to follow in trace files - these
    are not guaranteed to be valid across all SQL*Net releases and
    are for guidance only. Entries are assumed to be taken at trace
    level 16 to allow data packets to be seen. This will produce a
    LOT of trace output.

    Error information follows. Remember the error may be acceptable

    osntns: Calling address
    Shows address list constructed for a call OUT to a listener

    nricall: Making call with following address information: ...
    Shows the ACTUAL address being called from the above list

    nsopen: entry
    We are about to try and open a connection.

    nsopen: transport is open
    nsopen: error exit
    A connection to the called address has been made / failed.

    nsclose: ...
    An established connection is being closed - check nearby
    for errors.

    nscall: redirected
    The client has been redirected to a differenct address.
    The next step should be to call the new address. The address
    should appear in an earlier data packet.

    nspsend / nsprecv
    Outgoung / Incoming data


    Life is a journey, not a destination!

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