115 lines
7.2 KiB
HTML
115 lines
7.2 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 name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Commitment control with save-while-active" />
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<meta name="DC.Relation" scheme="URI" content="rzaiurzaiu310.htm" />
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<meta name="DC.Relation" scheme="URI" content="rzaiurzaiu327.htm" />
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<meta name="DC.Relation" scheme="URI" content="rzaiurzaiu334.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2004, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="commitoverview" />
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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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<!-- US Government Users Restricted Rights -->
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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>Commitment control with save-while-active</title>
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</head>
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<body id="commitoverview"><a name="commitoverview"><!-- --></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">Commitment control with save-while-active</h1>
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<div><p>This information applies if you are using commitment control and save-while-active
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to eliminate your save-outage time. This information applies only if you are
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not specifiying *NOCMTBDY for handling pending record changes on the SAVACTWAIT
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parameter.</p>
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<p>If an object receives updates under commitment control during the checkpoint
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processing phase of a save-while-active operation, the server saves the object
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at a commitment boundary. The server saves all objects that reach a checkpoint
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together at the same common commitment boundary. </p>
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<p>During the save preprocessing phase of a save-while-active request, the
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server ensures that it saves the objects commitment boundary as follows:</p>
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<ul><li>If the job performing the save-while-active request is not currently at
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a commitment boundary, the save request ends without saving any objects. This
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processing is the same for any save request.</li>
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<li>If updates are in progress for any objects in a group that are reaching
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a checkpoint together, the server delays the checkpoint. The checkpoint resumes
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when all of the transactions reach a commitment boundary. The server waits
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the amount of time specified on the second element of SAVACTWAIT parameter
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for these transactions to reach a commitment boundary. If uncommitted transactions
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still exist when the specified time expires, the save request ends.</li>
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<li>The server identifies which jobs have commitment definitions that are
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not currently at a commitment boundary and are delaying the checkpoint processing.
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The server waits until uncommitted transactions delay checkpoint processing
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for a group of objects for approximately 30 seconds. The server then sends
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a CPI8365 message to the QSYSOPR message queue for each job that is delaying
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the save-while-active request. After you receive these messages, you can then
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take the appropriate actions to bring all commitment definitions for those
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jobs to a commitment boundary.</li>
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<li>When no more commitment definitions are delaying the save-while-active
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job, the save-while-active job completes the checkpoint processing for the
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objects. After the checkpoint processing ends, the server allows changes for
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those objects under commitment control.</li>
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<li>If a commitment definition has uncommitted changes, it could possibly
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delay a save-while-active request. The uncommitted changes could delay the
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save-while-active request even though the changes are not for any database
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files. This situation can occur if you are journaling any of the database
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files to the same journal as the commitment definition is using for unrelated,
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uncommitted changes and if you specify a value greater than 0 for the second
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element of the SAVACTWAIT parameter.</li>
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<li>If an application is performing a read-for-update operation but no changes
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have been made, the application is considered to have started a commit cycle.
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The server allows a checkpoint to be established in the middle of a commit
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cycle as long as no changes have been made. Checkpoint processing does not
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stop if the application is performing only a read-for-update operation.</li>
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<li>The server temporarily delays a job that has all commitment definitions
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at a commitment boundary when both of the following are true: <ul><li>When it is likely that an application will change an object that is under
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commitment control</li>
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<li>When that object is reaching a checkpoint</li>
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</ul>
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The server holds that job until the objects reach a checkpoint, or the
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checkpoint processing for the object exceeds the time specified on the SAVACTWAIT
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parameter. During the time the server delays a job at a commitment boundary,
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the Work Active Job (WRKACTJOB) command displays <span class="uicontrol">CMTW</span> as
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the job status.</li>
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</ul>
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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="rzaiurzaiu310.htm">Save-while-active function</a></div>
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</div>
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<div class="relconcepts"><strong>Related concepts</strong><br />
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<div><a href="rzaiurzaiu334.htm">Performance considerations for save-while-active</a></div>
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</div>
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<div class="reltasks"><strong>Related tasks</strong><br />
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<div><a href="rzaiurzaiu327.htm">Checkpoint processing with save-while-active</a></div>
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</div>
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</div><div class="nested1" xml:lang="en-us" id="commitmentcontrolwithsave-while-activeandnocomtbdy"><a name="commitmentcontrolwithsave-while-activeandnocomtbdy"><!-- --></a><h2 class="topictitle2">Commitment control with save-while-active and *NOCOMTBDY</h2>
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<div><p>This information applies if you are using commitment control and save-while-active
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to eliminate your save-outage time. This information applies only if you specified
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*NOCMTBDY for handling pending record changes on the SAVACTWAIT parameter.</p>
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<ul><li>If the job performing the save-while-active request is not currently at
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a commitment boundary, the save continues and objects are saved with partial
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transactions.</li>
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<li>If updates other than pending record changes are in progress for any objects
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in a group that are reaching a checkpoint together, the server delays the
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checkpoint. The checkpoint resumes when all of the transactions reach a commitment
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boundary. The server waits the amount of time specified on the third element
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of SAVACTWAIT parameter for these transactions to reach a commitment boundary.
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If uncommitted transactions still exist when the specified time expires, the
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save request ends.</li>
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</ul>
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</div>
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</div>
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</body>
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</html>
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