83 lines
6.3 KiB
HTML
83 lines
6.3 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<head>
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<meta name="DC.Type" content="reference" />
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<meta name="DC.Title" content="End connections" />
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<meta name="abstract" content="Because remote connections use resources, connections that are no longer going to be used should be ended as soon as possible. Connections can be ended implicitly or explicitly." />
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<meta name="description" content="Because remote connections use resources, connections that are no longer going to be used should be ended as soon as possible. Connections can be ended implicitly or explicitly." />
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<meta name="DC.subject" content="distributed relational database, ending connections, DISCONNECT statement, RELEASE statement, connection management, DISCONNECT statement, ending connection, DDMCNV effect on, job attribute, DDMCNV, connection, DDM, connection management, DDMCNV effect on, ending DDM, Reclaim DDM connections (RCLDDMCNV) command, command (CL), Reclaim DDM connections (RCLDDMCNV)" />
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<meta name="keywords" content="distributed relational database, ending connections, DISCONNECT statement, RELEASE statement, connection management, DISCONNECT statement, ending connection, DDMCNV effect on, job attribute, DDMCNV, connection, DDM, connection management, DDMCNV effect on, ending DDM, Reclaim DDM connections (RCLDDMCNV) command, command (CL), Reclaim DDM connections (RCLDDMCNV)" />
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<meta name="DC.Relation" scheme="URI" content="rbafydistribsupport.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbafyc1.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbafyc2.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>End connections</title>
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</head>
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<body id="rbafydrdaconnect4"><a name="rbafydrdaconnect4"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">End connections</h1>
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<div><p>Because remote connections use resources, connections that are
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no longer going to be used should be ended as soon as possible. Connections
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can be ended implicitly or explicitly.</p>
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<div class="section"><p>Connections can be explicitly ended by either the DISCONNECT statement or
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the RELEASE statement followed by a successful COMMIT. The DISCONNECT statement
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can only be used with connections that use unprotected connections or with
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local connections. The DISCONNECT statement will end the connection when
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the statement is run. The RELEASE statement can be used with either protected
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or unprotected connections. When the RELEASE statement is run, the connection
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is not ended but instead placed into the released state. A connection that
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is in the release stated can still be used. The connection is not ended until
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a successful COMMIT is run. A ROLLBACK or an unsuccessful COMMIT will not
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end a connection in the released state.</p>
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</div>
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<div class="section"><p>When a remote SQL connection is established, a DDM network connection
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(APPC conversation or TCP/IP connection) is used. When the SQL connection
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is ended, the network connection may either be placed in the unused state
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or dropped. Whether a network connection is dropped or placed in the unused
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state depends on the DDMCNV job attribute. If the job attribute value is
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*KEEP and the connection is to another <span class="keyword">iSeries™</span> server,
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the connection becomes unused. If the job attribute value is *DROP and the
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connection is to another <span class="keyword">iSeries</span> server,
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the connection is dropped. If the connection is to a non-<span class="keyword">iSeries</span> server,
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the connection is always dropped. *DROP is desirable in the following situations:</p>
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<ul><li>When the cost of maintaining the unused connection is high and the connection
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will not be used relatively soon.</li>
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<li>When running with a mixture of programs, some compiled with RUW connection
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management and some programs compiled with DUW connection management. Attempts
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to run programs compiled with RUW connection management to remote locations
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will fail when protected connections exist.</li>
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<li>When running with protected connections using either DDM or DRDA<sup>®</sup>. Additional
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overhead is incurred on commits and rollbacks for unused protected connections.</li>
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</ul>
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</div>
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<div class="section"><p>The Reclaim DDM connections (RCLDDMCNV) command may be used to
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end all unused connections, if they are at a commit boundary.</p>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbafydistribsupport.htm" title="DB2 UDB for iSeries supports two levels of distributed relational database.">Distributed support</a></div>
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</div>
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<div class="relref"><strong>Related reference</strong><br />
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<div><a href="rbafyc1.htm" title="The application requester can implicitly connect to an application server.">Implicit connection management for the default activation group</a></div>
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<div><a href="rbafyc2.htm" title="The application requester can implicitly connect to an application server. Implicit SQL connection occurs when the application requester detects that the first SQL statement issued for the activation group is not a CONNECT statement with parameters.">Implicit connection management for nondefault activation groups</a></div>
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</div>
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</div>
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</body>
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</html>
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