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<h1 class="topictitle1">Control DDM conversations</h1>
<div><p>Normally, the DDM conversations associated with a source server
job are kept active until one of the conditions described in this topic is
met.</p>
<div class="section"> <ol><li>All the DDM files and remote files used in the conversation are closed
and unlocked (deallocated).</li>
<li>No other DDM-related functions like the use of the <span class="cmdname">Submit Remote
Command (SBMRMTCMD)</span> command or the <span class="cmdname">Display File Description
(DSPFD)</span> command (to display remote file information) are being performed.</li>
<li>No DDM-related function has been interrupted (by a break program, for
example) while running.</li>
<li>The <span class="cmdname">ENDCMTCTL</span> command was issued (if commitment control
was used with a DDM file).</li>
<li>No distributed relational database architecture-related functions are
being performed.</li>
<li>The activation group, in which the DDM conversation was started, ends.
A DDM conversation is not dropped when the activation group ends under the
following conditions: <ul><li>The DDM conversation is scoped to the job level.</li>
<li>The commitment control of the activation group is scoped to the job level,
and a unit of work is outstanding. The conversation remains until the next
job level commit or rollback, or until the job ends.</li>
</ul>
</li>
<li>The job or routing step ends.</li>
</ol>
</div>
<div class="section"><p>If <em>1</em>, <em>2</em>, and <em>3</em> are true and the source job
or activation group has not ended, the conversation is considered to be <em>unused</em>,
that is, the conversation is kept active but no requests are being processed.</p>
</div>
<div class="section"><p> DDM conversations can be active and unused because the default
value of the DDMCNV job attribute is *KEEP. This is desirable for the usual
situation of a source server program accessing a remote file for multiple
I/O operations; these operations are handled one at a time, as shown in <a href="rbae5xs3xsrc.htm#rbae5xs3xsrc__rbae5iorqst">Figure 2</a> and explained in
the text following it.</p>
</div>
<div class="section"><p>If multiple DDM requests are to be made in a job and the DDM files
are being continually opened and closed in the job, *KEEP should be used to
keep an unused DDM conversation active. (However, as long as one DDM file
remains open or locked, *KEEP has no effect.)</p>
</div>
<div class="section"><p>For source jobs that access remote files but do not access data
records in them, it might be desirable, depending on the frequency of the
file accesses, to automatically drop each DDM conversation at the completion
of each file-related source job request. Whether the conversation in the source
job is kept active or automatically dropped during the time a conversation
is unused is determined by the DDMCNV job attribute value (*KEEP or *DROP).</p>
</div>
<div class="section"><p>Regardless of the value of the DDMCNV job attribute, conversations
are dropped when one of the following things occurs: </p>
<ul><li>The job ends.</li>
<li>The activation group ends. A DDM conversation is not dropped when the
activation group ends under the following conditions: <ul><li>The DDM conversation is scoped to the job level.</li>
<li>The commitment control of the activation group is scoped to the job level,
and a unit of work is outstanding. The conversation remains until the next
job level commit or rollback, or until the job ends.</li>
</ul>
</li>
<li>The job initiates a<span class="cmdname"> Reroute Job (RRTJOB)</span> command.</li>
</ul>
<p>Unused conversations within an active job can also be dropped by the <span class="cmdname">Reclaim
DDM Conversations (RCLDDMCNV)</span> or <span class="cmdname">Reclaim Resources (RCLRSC)</span> command.
Errors, such as communications line failures, can also cause conversations
to drop.</p>
</div>
</div>
<div>
<ul class="ullinks">
<li class="ulchildlink"><strong><a href="rbae5disddmcnv.htm">Display DDMCNV values (WRKJOB command)</a></strong><br />
To display the current value (*KEEP or *DROP) of the DDMCNV job
attribute for your source job, you can use menu option 2 (Work with definition
attributes) on the <span class="cmdname">Work with Job (WRKJOB)</span> Command display.
You can also find out the value within a CL program by using the <span class="cmdname">Retrieve
Job Attributes (RTVJOBA)</span> command.</li>
<li class="ulchildlink"><strong><a href="rbae5chgcnv.htm">Change DDMCNV values (CHGJOB) command</a></strong><br />
To control whether the server is to automatically reclaim (or drop)
DDM conversations in a source job whenever they become unused, the server
default *KEEP can be changed to *DROP by using a <span class="cmdname">Change Job (CHGJOB)</span> command.
If the value is left as *KEEP, the <span class="cmdname">Reclaim DDM Conversations (RCLDDMCNV)</span> or <span class="cmdname">Reclaim
Resources (RCLRSC)</span> command can be used at any time to drop all DDM
conversations (within that job only) that currently do not have any active
users.</li>
<li class="ulchildlink"><strong><a href="rbae5rclres.htm">Reclaim DDM resources (RCLRSC and RCLDDMCNV commands)</a></strong><br />
When an <span class="keyword">iSeries™</span> user
wants to ensure that the resources for all APPC conversations (including DDM
conversations) that are no longer active are returned to the server, the <span class="cmdname">Reclaim
Resources (RCLRSC)</span> command can be used.</li>
</ul>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rbae5otherremote.htm" title="Besides accessing remote files for data record I/O operations, other operations related to remote files can be performed. These are briefly described in these topics.">Other DDM-related functions involving remote files</a></div>
</div>
<div class="relconcepts"><strong>Related concepts</strong><br />
<div><a href="rbae5xs3xsrc.htm" title="When an application program or user in a source server job first refers to a DDM file, several actions occur as part of processing the request on the source server.">iSeries server as the source server for DDM</a></div>
</div>
<div class="relref"><strong>Related reference</strong><br />
<div><a href="rbae5recddm.htm" title="The Reclaim DDM Conversations (RCLDDMCNV) command is used to reclaim all DDM source server conversations that are not currently being used by a source job.">RCLDDMCNV (Reclaim DDM Conversations) command</a></div>
<div><a href="rbae5ddm_rclrsc.htm" title="The Reclaim Resources (RCLRSC) command, like the Reclaim DDM Conversations (RCLDDMCNV) command, can be used to reclaim all DDM conversations that currently have no users in the job.">RCLRSC (Reclaim Resources) command</a></div>
<div><a href="rbae5ddmcnv.htm" title="The DDMCNV parameter is a job-related parameter that controls whether Advanced Program-to-Program Communication (APPC) or iSeries conversations in the job that is allocated for DDM use (that is, DDM conversations) are to be automatically dropped or kept active for the source job.">DDMCNV parameter considerations</a></div>
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