SWITCH STREAM command: Difference between revisions
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<dd>System manager | <dd>System manager | ||
<dt>Function | <dt>Function | ||
<dd>You can switch streams | <dd>You can switch streams — parallel, ring, concatenated, GDG — to the next member at any time. | ||
</dl> | </dl> | ||
==Syntax== | ==Syntax== | ||
<p class="syntax">SWITCH STREAM streamname | <p class="syntax">SWITCH STREAM <span class="term">streamname</span> [RESET] | ||
</p> | </p> | ||
< | Where: | ||
<table> | |||
<tr><th>streamname</th> | |||
<td><var>CCAJRNL</var>, <var>CCAJLOG</var>, <var>CHKPOINT</var>, or <var>CHKPNTS</var>. The command is valid only for these streams.</td></tr> | |||
<tr><th><var>RESET</var></th> | |||
<td>This optional parameter causes any disabled parallel GDG members to be reopened during the switch. | |||
<p> | |||
Valid only when <var>CCAJLOG</var> or <var>CCAJRNL</var> are defined as a parallel stream defined with GDG members, as in the following example, which specifies two complete copies of CCAJLOG using GDGs as a base:</p> | |||
<p class="code">DEFINE STREAM CCAJLOG … PARALLEL=(P1,P2) … | |||
DEFINE STREAM P1 … GDG=(D1) … | |||
DEFINE STREAM P2 … GDG=(D2) … | |||
DEFINE DATASET D1…. | |||
DEFINE DATASET D2… </p> | |||
<p>Note: <var>RESET</var> of <var>CCAJNRL</var> is only possible as version 8.0 of Model 204. A custom zap may be available for earlier versions.</p> | |||
</td></tr> | |||
</table> | |||
==Usage notes== | ==Usage notes== | ||
If you specify: | <ul> | ||
<li>If you specify: | |||
<ul> | <ul> | ||
<li> | <li>A journal stream (<var>CCAJRNL</var> or <var>CCAJLOG</var>): the currently active data set is closed and the next data set defined to the stream is opened. </li> | ||
< | |||
</li> | |||
<li> | <li>A checkpoint stream (<var>CHKPOINT</var> or <var>CHKPNTS</var>): the currently active data set in the stream is closed after the next record is written to the data set.</li> | ||
< | </ul></li> | ||
</ | |||
<li>If a <code>SWITCH STREAM CCAJRNL</code> command is issued during <code>CHECKPOINT EXTENDED QUIESCE</code> command processing, the journal is switched, a new checkpoint is issued, and the duration of the extended quiesce time-out set in <var>[[CPQZSECS parameter|CPQZSECS]]</var> is reset to its maximum, original value (disregarding the already-elapsed time).</li> | |||
< | |||
<li>A <code>SWITCH STREAM CCAJRNL RESET</code> command is only allowed during <code>CHECKPOINT EXTENDED QUIESCE</code> command processing. Ie</li> | |||
<p class="code">CHECKPOINT SET E Q | |||
CHECKPOINT | |||
SWITCH STREAM CCAJRNL RESET | |||
CHECKPOINT UNSET E Q | |||
</p> | |||
<li>For an extensive discussion about using the <var>SWITCH STREAM</var> command, see [[Tracking system activity (CCAJRNL, CCAAUDIT, CCAJLOG)#SWITCH STREAM command|Tracking system activity (CCAJRNL, CCAAUDIT, CCAJLOG)]]. </li> </ul> | |||
==See also== | |||
<ul> | |||
<li>[[DEFINE STREAM command]] </li> | |||
<li>[[COPY STREAM command]] </li> | |||
<li>[[Configuring checkpoint and journal data streams]] </li> | |||
</ul> | |||
[[Category: System manager commands]] | [[Category: System manager commands]] | ||
[[Category:Commands]] | [[Category: Commands]] | ||
Latest revision as of 22:05, 13 October 2024
Summary
- Privileges
- System manager
- Function
- You can switch streams — parallel, ring, concatenated, GDG — to the next member at any time.
Syntax
SWITCH STREAM streamname [RESET]
Where:
| streamname | CCAJRNL, CCAJLOG, CHKPOINT, or CHKPNTS. The command is valid only for these streams. |
|---|---|
| RESET | This optional parameter causes any disabled parallel GDG members to be reopened during the switch.
Valid only when CCAJLOG or CCAJRNL are defined as a parallel stream defined with GDG members, as in the following example, which specifies two complete copies of CCAJLOG using GDGs as a base: DEFINE STREAM CCAJLOG … PARALLEL=(P1,P2) … DEFINE STREAM P1 … GDG=(D1) … DEFINE STREAM P2 … GDG=(D2) … DEFINE DATASET D1…. DEFINE DATASET D2… Note: RESET of CCAJNRL is only possible as version 8.0 of Model 204. A custom zap may be available for earlier versions. |
Usage notes
- If you specify:
- A journal stream (CCAJRNL or CCAJLOG): the currently active data set is closed and the next data set defined to the stream is opened.
- A checkpoint stream (CHKPOINT or CHKPNTS): the currently active data set in the stream is closed after the next record is written to the data set.
- If a
SWITCH STREAM CCAJRNLcommand is issued duringCHECKPOINT EXTENDED QUIESCEcommand processing, the journal is switched, a new checkpoint is issued, and the duration of the extended quiesce time-out set in CPQZSECS is reset to its maximum, original value (disregarding the already-elapsed time). - A
SWITCH STREAM CCAJRNL RESETcommand is only allowed duringCHECKPOINT EXTENDED QUIESCEcommand processing. Ie - For an extensive discussion about using the SWITCH STREAM command, see Tracking system activity (CCAJRNL, CCAAUDIT, CCAJLOG).
CHECKPOINT SET E Q CHECKPOINT SWITCH STREAM CCAJRNL RESET CHECKPOINT UNSET E Q