108 lines
7.2 KiB
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108 lines
7.2 KiB
HTML
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<meta name="DC.Title" content="Database jobs" />
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<meta name="abstract" content="The following is a list of database jobs." />
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<title>Database jobs</title>
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<body id="rzaksdatabasejobs"><a name="rzaksdatabasejobs"><!-- --></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">Database jobs</h1>
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<div><p>The following is a list of database jobs.</p>
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<dl><dt class="dlterm">Qdbfstccol (database file statistic collection)</dt>
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<dd>This job collects database file statistics. These statistics are crucial
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to correct database query optimization.</dd>
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<dt class="dlterm">Qdbsrvxr (database cross-reference) and Qdbx###xr for independent disk
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pool group ###</dt>
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<dd>This job maintains each of the file level system cross-reference files
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in Qsys. These files contain cross-reference information about database files
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and SQL information across the system. The files all begin with the prefix
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of Qadb in library Qsys. The primary file that must be maintained is Qadbxref,
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the cross-reference file. This file contains a record of each physical database,
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logical database, DDM, and Alias file on the system. Qdbsrvxr activates when
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a file is created, changed, deleted, restored, renamed, or its ownership is
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changed.</dd>
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<dt class="dlterm">Qdbsrvxr2 (database cross-reference 2) and Qdbx###xr2 for independent
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disk pool group ###</dt>
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<dd>This job maintains the two field level cross-reference files. Qadbifld
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in library Qsys is the field cross-reference file. Qadbkfld in library Qsys
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is the key field cross-reference file. Qdbsrvxr2 is activated when a file
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is created, changed or deleted.</dd>
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<dt class="dlterm">Qdbsrv01 (database server) and Qdbs###v01 for independent disk pool group
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###</dt>
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<dd>This job can be viewed as the database maintenance task dispatcher. The
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number of database server jobs on the system is one plus twice the number
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of processors, or one plus twice the number of ASPs, whichever is greater.
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The minimum started is five. Qsbsrv01 is the main system job assigning work
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to the others. Typically, Qdbsrv01 will be most active immediately after restoring
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a library that contains database files. Its function includes:<ul><li>Signaling to the system-managed access path protection (SMAPP) Licensed
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Internal Code (LIC) tasks that new access paths have been restored. SMAPP
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then determines whether these access paths need to be protected.</li>
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<li>Preparing the list of access paths that are required to be rebuilt because
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the access paths were not restored.</li>
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</ul>
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<p>Of the remaining database server jobs, the first half process high-priority
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requests, and the second half process low-priority requests. (Example: Qdbsrv02
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through Qdbsrv05 are high priority, Qdbsrv06 through Qdbsrv09 are low priority.)</p>
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</dd>
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<dt class="dlterm">Qdbsrvxx (database server, high priority) and Qdbs###vxx for independent
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disk pool group ###</dt>
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<dd>These jobs perform journal and commitment control maintenance for the
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system and are considered quick or short-running work.</dd>
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<dt class="dlterm">Qdbsrvxx (database server, low priority) and Qdbs###vxx for independent
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disk pool group ###</dt>
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<dd>These jobs perform access path maintenance on user data files. Typically,
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these jobs are inactive, but in certain cases, they might activate to perform
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access path rebuilds. Some reasons why these jobs might be active are:<ul><li>Restoring database files that were not saved with access paths</li>
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<li>Restoring logical files without the physical file they are based on</li>
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<li>Canceling of an Rgzpfm command while in process</li>
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<li>Invalidation of an index due to damage found in the index</li>
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<li>Post-iServer installation activity to complete cross-reference or other
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DB upgrade activity</li>
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<li>Constraint verification</li>
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</ul>
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</dd>
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<dt class="dlterm">Qqqtemp1 and Qqqtemp2 (database parallelism)</dt>
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<dd>The database parallelism system jobs perform asynchronous database processing
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for the DB2<sup>®</sup> Multisystem.
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If users query distributed files, the jobs are used to speed up the queries
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by doing certain tasks in parallel.</dd>
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</dl>
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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="rzakssystemjobs.htm" title="System jobs are created by the operating system to control system resources and perform system functions. System jobs run when the iSeries server starts or when an independent disk pool is varied on. These jobs perform a variety of tasks from starting the operating system, to starting and ending subsystems, to scheduling jobs.">System jobs</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="rzakssystemstartupjobs.htm" title="Startup jobs are system jobs that run at IPL. They handle the tasks that get the operating system environment up and ready for work. The following is a list of the various system startup jobs.">System startup jobs</a></div>
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<div><a href="rzakssystemarbiters.htm" title="The system arbiters (QSYSARB and QSYSARB2 through QSYSARB5), started by an SCPF system job, provide the environment for the running of high-priority functions. They allow subsystems to start and end and keep track of the state of the system (for example, a restricted state).">System arbiters</a></div>
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<div><a href="rzakssystemcommjob.htm" title="This topic contains a list of system communication jobs.">System communication jobs</a></div>
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<div><a href="rzakssystemotherjob.htm" title="This article contains is a list of other kinds of system jobs.">Other system jobs</a></div>
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</div>
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</div>
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