15.10 - Syntax - Access Module

Teradata Tools and Utilities Access Module Reference

prodname
Access Module
vrm_release
15.10
category
Programming Reference
featnum
B035-2425-035K

Syntax

Note: When defining parameter attribute in an initialization string or in a parameter file (‑parmfile), keywords are case‑insensitive, and unrecognized keywords with invalid values cause an immediate termination.

where:

 

Table 9: Initialization Syntax 

Syntax Element

Description

parmfile <ObjectName>

Optional object name for the file in which more access module parameters may reside. On MVS, this is a DDNAME that is defined in the JCL.

  • Each line in the parameter file may have a single keyword (parameter) and its value(s).
  • Empty lines will be ignored.
  • Lines beginning with the pound # character will be ignored.
  • Keywords must begin in the first column.
  • See “Example: JCL Excerpt” on page 95.

    help

    Optional keyword that requests the display of a list of valid parameter file keywords.

    QMGR
    <WebSphere MQ Manager Name>

    Required parameter that specifies the WebSphere MQ Manager, which coordinates and routes messages to the appropriate queue.

    If this parameter is not provided, the operator terminates with a fatal error.

    qnm<WebSphere Qname>

    Required keyword that specifies the queue name.

    CKFILE
    <ObjectName/
    Statement>

    Optional parameter that allows a request for checkpoint support through the use of disk facilities.

    On MVS/ESA, the <ObjectName> to which you want to write checkpoint data is a DDNAME. For example:

    CKFILE <DDNAME> 

    where <DDNAME> refers to a previously defined DDNAME within the JCL.

    On MVS/USS, <Statement> defines the DD statement. For example:

    ckfile dsorg=ps,dsn=tpt.x2cuss,disp=new,ndisp=catlg,
    cdisp=catlg,track,primary=100,secondary=20,recfm=u,
    blksize=32760,lrecl=0 

    For restarts, set the disp value to shr. If the disposition value is equal to new, and the data set already exists, the allocation and job will fail. Refer to IBM MVS documentation for explanations of other parameters.

    Enough disk storage to hold all checkpointed messages, plus space to copy the file, is required.

    If this parameter is not provided, no filebased checkpoint support is available.

    Note: On workstation platforms, to facilitate a checkpoint during a recovery, a temporary file is created and resides in the same directory as the checkpoint file. Named MQAMtmp.<pid>, this file supports the process of removing obsolete records from the checkpoint file. The file is removed upon completion of the checkpoint.

    FLUSH <Yes/No>

    Optional parameter that ensures all checkpoint data is written to the media. If you select Yes, the access module writes all checkpoint data to the media. You must have filebased checkpoint support in effect to use this option.

    If you select No, checkpoint data is not written to the media. Significantly fewer system resources are consumed if you choose this option.

    If this parameter is not provided, the default is No.

    TDM <Yes/No>

    Optional parameter that allows termination of duplicate messages. If you select Yes, the access module returns an EOF if a duplicate message is suspected. If you select No, the access module returns the duplicate message.

    Duplicate messages only occur during a recovery from a crash or ABEND that occurred between the time that a message was written to the checkpoint file and the time that the message was committed through a MQCMIT command.

    If this parameter is not provided, the default is Yes.

    BKSZ <MaximumMsgSize>

    Optional parameter that specifies the block size for WebSphere MQ messages. You should define the block large enough to accommodate the largest message anticipated.

    The parameter BLKZ cannot be a value that exceeds the value of the DCB BLKSIZE specified in the JCL within the checkpoint DD statement.

    Acceptable Range: 1 byte–16 MB

    If this parameter is not provided, the default is 32,000 bytes.

    If an unacceptable value is provided, the following error is issued, and the access module fails:

    Teradata WebSphere MQ AMOD/OpenCkPtFile(!ERROR!): Checkpoint DD DCB BLKSIZE (<DCB BLKSIZE value>) less than potential required (<BLKZ + 4>) (a function of keyword 'BKSZ')

    RWAIT <MaximumSeconds>

    Optional parameter that specifies the MQGET wait time, which is the time that MQGET waits if no message is immediately available. MQGET is called iteratively in a loop with maximum iterations set to the read wait interval value. To ensure that signals handlers are called, a sleep(0) call will be within the body of the loop.

    Acceptable Range: Enter 1–600 seconds or 1 for unlimited wait time.

    If this parameter is not provided, the default is 1 second.

    A zero length message encountered on the queue will trigger an EOF to the application. This may be useful when using the unlimited wait feature (RWAIT 1).

    ALLOWSIGNALS <Yes/No>

    Optional parameter that determines whether signals handlers are called. The default is Yes, which calls signal handlers while waiting for message arrive. If No, signal handlers are not called.

    OWAIT <MaximumSeconds>

    Optional parameter that specifies the MQOPEN retry time interval, which is the wait time between an unsuccessful MQOPEN call and the next call attempt.

    Acceptable Range: 1–600 seconds

    See the OTENACITY parameter for related information.

    If this parameter is not provided, the default is 5 seconds.

    OTENACITY

    <MaximumSeconds>

    Optional parameter that specifies the amount of time that the access module attempts to open the designated Queue via an MQOPEN call.

    Acceptable Range: 1–6000 seconds

    If this parameter is not provided, the default is 5 seconds.

    LOGFILL<Yes/No>

    Optional parameter that packs log records to minimize wasted disk space. If you select Yes, the module fills each disk block to the block size specified in the Data Control Block. If you select No, the module fills each disk block with a single message.

    If this parameter is not provided, the default is Yes.

    LOG <LogObjectName
    /LogObjectStatement>

    Optional parameter that requests and directs a Log object. All messages received from MQ are echoed to the specified log.

    On MVS/USS, <LogObjectStatement> defines the DD statement.

    Example

    log dsorg=ps,dsn=tpt.x2luss,disp=new,ndisp=catlg,
    cdisp=catlg,track,primary=100,secondary=20,recfm=u,
    blksize=2000,lrecl=0

    To add to an existing log, set the disp value to mod.Setting the disp value to new begins a new log, therefore a data set should not already exist. Refer to IBM MVS documentation for explanations of other parameters.

    If this parameter is not provided, no log is maintained.

    ALTERNATELOG

    <DDNAME>

    Optional parameter for MVS version of WebSphere MQ Access Module that opens an alternate log. Specifying an alternate log allows you to close the primary log for external processing. An external notify exit routine sends a signal to the access module to swap between the destination defined by LOG <DDNAME> and that defined by AlternateLog <DDNAME>. Swaps between the logs will occur each time a signal is received.

    If this parameter is not provided, no alternate log is maintained.

    TLF <Yes/No>

    Optional parameter that specifies whether a log failure should cause a fatal error or not. If you select Yes, the access module terminates if it is unable to write to the log for any reason. If you select No, logging is disabled while the access module continues to operate.

    If this parameter is not provided, the default is Yes.

    MQEX

    Optional parameter that allows the process to open the MQ named queue exclusively.

    If this parameter is not provided, it will not be possible for another process to open this queue.

    CONVERT <Yes/No>

    Optional parameter that requests the WebSphere MQ message character set. If you select Yes, the access module converts data to the resident character set. If you select No, the access module processes messages without converting them.

    If this parameter is not provided, the default is No.

    TRCL<level>
    <ObjectName>

    Optional parameter for diagnostics, where levels 0 through 4 indicate:

    0: no diagnostic trace

    1: job events only reported

    2: I/O events

    3: I/O buffers

    4: detailed information

    The default is zero (0), indicating no trace. Indicate a level of 1 or higher for diagnostics or checkpoint support.

    The filename designation on MVS is a DDNAME.

    Note: The load utility you are using, not the access module nor the DataConnector, creates job logs.

    CHNL<name>

    Establishes the WebSphere MQ channel name on Windows platforms. For UNIX platforms, the channel name is defined using environmental variables (for example, MQSERVER) via the shell and system.

    For more about proper syntax and use of environmental variables, see WebSphere documentation at http://ibm.com/webspheremq.

    SRVR<name>[:port]

    Establishes the WebSphere MQ server name on Windows platforms. For UNIX platforms, the server name is defined using environmental variables (for example, MQSERVER), via the shell and system.

    For more about proper syntax and use of environmental variables, see WebSphere documentation at http://ibm.com/webspheremq.