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<h1 class="topictitle1">How journal management works</h1>
<div><p>Use journal management to create an object called a <span class="uicontrol">journal</span>.
Use a journal to define which objects you want to protect. You can have more
than one journal on your system. A journal can define protection for more
than one object.</p>
<p>You can journal the objects that are listed below:</p>
<ul><li>Database physical files</li>
<li>Access paths</li>
<li>Data areas</li>
<li>Data queues</li>
<li>Integrated file system objects (stream files, directories, and symbolic
links).</li>
</ul>
<div class="section"><h4 class="sectiontitle">Journal entries</h4><p>The system keeps a record of changes
you make to objects that are journaled and of other events that occur on the
system. These records are called journal entries. You can also write journal
entries for events that you want to record, or for objects other than the
object that you want to protect with journaling.</p>
<p>For example, some journal
entries identify activity for a specific database record such as add, update,
or delete. (If the updated object image after the update is the same as the
image before the update, then journal entries are not deposited for that update.)
Also journal entries identify activity such as a save, open, or close operation
for an object. Journal entries can also identify other events that occur,
such as security-relevant events on the system or changes made by dynamic
performance tuning. The Journal entry information link below describes
all the possible journal entry types and their contents.</p>
<p>Each journal
entry can include additional control information that identifies the source
of the activity, including the user, job, program, time, and date. The entries
that the system deposits for a journaled object reflect the changes made to
that journaled object. For example, the entries for changes to database records
can include the entire image of the database record, not just the changed
information.</p>
</div>
<div class="section"><h4 class="sectiontitle">Journal receivers</h4><p>The system writes entries to an
object called a <span class="uicontrol">journal receiver</span>. The system sends
entries for all the objects associated with a particular journal to the same
journal receiver.</p>
<p>You can attach journal receivers to a journal by using iSeries™ Navigator
or the Create Journal (CRTJRN) and Change Journal (CHGJRN) commands. The system
adds journal entries to the attached receiver. Journal receivers that are
no longer attached to a journal and are still known to the system are <span class="uicontrol">associated</span> with
that journal. Use the Work with Journal Attributes (WRKJRNA) command to see
a list of receivers associated with a journal.</p>
<p>The system adds an entry
to the attached journal receiver when an event occurs to a journaled object.
The system numbers each entry sequentially. For example, it adds an entry
when you change a record in a journaled database file member. Journal entries
contain information that identifies:</p>
<ul><li>Type of change</li>
<li>Record that has been changed</li>
<li>Change that has been made to the record</li>
<li>Information about the change (such as the job being run and the time of
the change)</li>
</ul>
<p>When you are journaling objects, changes to the objects are added
to the journal receiver. The system does not journal data that you retrieved
but did not change. If the logical file record format of a database file does
not contain all the fields that are in the dependent physical file record
format, the journal entry still contains all the fields of the physical file
record format. In addition, if you are journaling access paths, entries for
those access paths are added to the journal. If the updated physical file
image after the update is the same as the image before the update, and if
the file has no variable length fields, then journal entries are not deposited
for that update. If the updated data area image after the update is the same
as the image before the update, then journal entries are not deposited for
that update. If the attribute that was requested to be changed was already
that value, then journal entries are not deposited for that change.</p>
</div>
<div class="section"><h4 class="sectiontitle">Summary of the journaling process</h4><p>The following
figure shows a summary of journal processing. Objects A and B are journaled;
object C is not. Programs PGMX and PGMY use object B. When you make a change
to object A or B, the following occurs:</p>
<ul><li>The change is added to the attached journal receiver.</li>
<li>The journal receiver is written to auxiliary storage.</li>
<li>The changes are written to the main storage copy of the object.</li>
</ul>
<p>Object C changes are written directly to the main storage copy of
the object because it is not being journaled. Only the entries added to the
journal receiver are written immediately to auxiliary storage. Changes against
the object may stay in main storage until the object is closed.</p>
<br /><img src="rzaki502.gif" alt="Illustration showing journaling overview" /><br /><p>You can also take advantage of the remote journal function. The
remote journal function allows you to associate a journal on a remote system
with a journal on a local system. Journal entries on the local system are
replicated to the remote journal receiver.</p>
</div>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzakiconcepts.htm" title="This topic explains how journal management works, why to use it, and how it affects your system.">Journal management concepts</a></div>
</div>
<div class="relconcepts"><strong>Related concepts</strong><br />
<div><a href="rzakijrnentry.htm" title="This topic provides information and tasks for working with journal entries.">Journal entry information</a></div>
<div><a href="rzakiremotekickoff.htm" title="Use remote journal management to establish journals and journal receivers on a remote system that are associated with specific journals and journal receivers on a local system. Remote journal management replicates journal entries from the local system to the journals and journal receivers that are located on the remote system after they have been established.">Remote journal management</a></div>
</div>
<div class="relref"><strong>Related reference</strong><br />
<div><a href="../cl/crtjrn.htm">Create Journal (CRTJRN) command</a></div>
<div><a href="../cl/chgjrn.htm">Change Journal (CHGJRN) command</a></div>
<div><a href="../cl/wrkjrna.htm">Work with Journal Attributes (WRKJRNA) command</a></div>
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