APSYPAGE parameter: Difference between revisions

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==Description==
==Description==
<p>Activates the APSY Precompiled Procedures in Storage feature by specifying a number of 4K operating system pages.</p>
<p>
<p>For IBM z/OS systems only.</p>
While the feature was available, the <var>APSYPAGE</var> parameter activated the [[System requirements for Application Subsystems#Activating the APSY Precompiled Procedures in Storage feature|APSY Precompiled Procedures in Storage feature]] by specifying a number of 4K-byte operating system pages.</p>
<p>APSYPAGE was implemented to take advantage of the MVPG machine language instruction which moved an entire hardware page (4K) with a single instruction and which, at the time, had significantly better performance than the stream-oriented moves used by standard APSY load. However, recent hardware models actually seem to have better performance for the stream-oriented moves so it is recommended that customers disable the APSYPAGE feature by setting APSYPAGE to 0.</p>
<p>
For IBM z/OS systems only.</p>
<p>
<var>APSYPAGE</var> was implemented to take advantage of the <code>MVPG</code> machine language instruction which moved an entire hardware page (4K bytes) with a single instruction and which, at the time, had significantly better performance than the stream-oriented moves used by standard APSY load. However, recent hardware models actually seem to have better performance for the stream-oriented moves.</p>
<p class="warn"><b>Note:</b> As of Model&nbsp;204 7.5, it is recommended that customers who have been using the <var>APSYPAGE</var> parameter <var class="term">disable the APSYPAGE feature</var> by setting <var>APSYPAGE</var> to 0. <br />As of Model&nbsp;204 7.7, setting <var>APSYPAGE</var> to a non-zero value results in an error and <var class="term">prevents the Online from coming up</var>. </p>
<p>
Instead of <var>APSYPAGE</var>, you can use the following:</p>
<ul>
<li>The <var>[[RESPAGE parameter|RESPAGE]]</var> parameter (recommended for performance).
<p>
Set <var>RESPAGE</var> to the former value of <var>APSYPAGE</var>. Both <var>RESPAGE</var> and <var>APSYPAGE</var> specify the number of 4096-byte pages allocated for the respective feature. </p></li>
 
<li>The <var>[[TEMPPAGE parameter|TEMPPAGE]]</var> parameter.
<p>
<var>TEMPPAGE</var> pages are larger so fewer are needed. <var>TEMPPAGE</var> pages are 6184 bytes, with 6144 used to hold data and 40 bytes as page trailers. Divide the former <var>APSYPAGE</var> value by 1.5 before adding to <var>TEMPPAGE</var>. </p></li>
</ul>


<p>When switching between using and not using APSYPAGE, the number of in-memory CCATEMP pages ([[TEMPPAGE parameter|TEMPPAGE]]) should be adjusted to compensate for the pages used or not used by APSYPAGE. That is, if APSYPAGE is set to zero, TEMPPAGE should be increased by the corresponding amount, and if APSYPAGE is set to a non-zero value, TEMPPAGE can be decreased by the corresponding amount. Note however, that the units for TEMPPAGE are 6184 ([[PAGESZ parameter|PAGESZ]]) bytes while the units for TEMPPAGE are 4096 (hardware page size) bytes so TEMPPAGE units should be multiplied by 1.5 to convert them to APSYPAGE units and APSYPAGE units should be divided by 1.5 to convert them to TEMPAGE units. 4096 times 1.5 actually equals 6144 but that's actually the amount used on each TEMPPAGE page &mdash; 40 bytes are used as page trailers and not used to hold actual data.</p>
[[Category:System parameters]]
[[Category:System parameters]]
[[Category:Parameters]]
[[Category:Parameters]]

Latest revision as of 00:17, 28 September 2016

APSYPAGE is obsolete as of 7.6

Summary

Default value
0
Parameter type
System
Where set
On User 0's parameter line
Related products
All
Introduced
Model 204 V5.1

Description

While the feature was available, the APSYPAGE parameter activated the APSY Precompiled Procedures in Storage feature by specifying a number of 4K-byte operating system pages.

For IBM z/OS systems only.

APSYPAGE was implemented to take advantage of the MVPG machine language instruction which moved an entire hardware page (4K bytes) with a single instruction and which, at the time, had significantly better performance than the stream-oriented moves used by standard APSY load. However, recent hardware models actually seem to have better performance for the stream-oriented moves.

Note: As of Model 204 7.5, it is recommended that customers who have been using the APSYPAGE parameter disable the APSYPAGE feature by setting APSYPAGE to 0.
As of Model 204 7.7, setting APSYPAGE to a non-zero value results in an error and prevents the Online from coming up.

Instead of APSYPAGE, you can use the following:

  • The RESPAGE parameter (recommended for performance).

    Set RESPAGE to the former value of APSYPAGE. Both RESPAGE and APSYPAGE specify the number of 4096-byte pages allocated for the respective feature.

  • The TEMPPAGE parameter.

    TEMPPAGE pages are larger so fewer are needed. TEMPPAGE pages are 6184 bytes, with 6144 used to hold data and 40 bytes as page trailers. Divide the former APSYPAGE value by 1.5 before adding to TEMPPAGE.

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