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<h1 class="topictitle1">Non-<span class="keyword">DB2 Universal Database for iSeries</span> to <span class="keyword">DB2 Universal Database for iSeries</span> blocking</h1>
<div><div class="section"><p>Blocking will not occur if:</p>
<ul><li>The cursor is updatable (see <a href="rbal1blocksummary.htm">note
1</a>).</li>
<li>The cursor is potentially updatable (see <a href="rbal1blocksummary.htm">note
2</a>).</li>
<li>A precompile or bind option is used that caused the package default value
to be force-single-row protocol. <ul><li>For DB2
Universal Database™ for iSeries™, there is no option to do this.</li>
<li>For DB2
Universal Database for VM, this is the NOBLOCK keyword on SQLPREP (the
default).</li>
<li>For DB2<sup>®</sup> for OS/2<sup>®</sup> (DB2/2),
this is /K=NO on SQLPREP or SQLBIND.</li>
</ul>
</li>
<li>The row size is greater than approximately 0.5 multiplied by QRYBLKSIZ.
The default and maximum QRYBLKSIZ values are as follows: <div class="p">
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="border" border="1" rules="all"><caption>Table 1. QRYBLKSIZ</caption><thead align="left"><tr><th valign="top" width="25.510204081632654%" id="d0e75">DB2 product</th>
<th valign="top" width="31.63265306122449%" id="d0e79">Default QRYBLKSIZ</th>
<th valign="top" width="42.857142857142854%" id="d0e81">Maximum QRYBLKSIZ in Version 8</th>
</tr>
</thead>
<tbody><tr><td valign="top" width="25.510204081632654%" headers="d0e75 ">DB2 Universal Driver for SQLJ and JDBC</td>
<td valign="top" width="31.63265306122449%" headers="d0e79 ">32 KB</td>
<td valign="top" width="42.857142857142854%" headers="d0e81 ">32 KB</td>
</tr>
<tr><td valign="top" width="25.510204081632654%" headers="d0e75 ">DB2 Universal Database for z/OS<sup>®</sup></td>
<td valign="top" width="31.63265306122449%" headers="d0e79 ">32 KB</td>
<td valign="top" width="42.857142857142854%" headers="d0e81 ">64 KB</td>
</tr>
<tr><td valign="top" width="25.510204081632654%" headers="d0e75 ">DB2 Universal Database for VM</td>
<td valign="top" width="31.63265306122449%" headers="d0e79 ">8 KB</td>
<td valign="top" width="42.857142857142854%" headers="d0e81 ">32 KB</td>
</tr>
<tr><td valign="top" width="25.510204081632654%" headers="d0e75 "><span>DB2 Universal Database for Linux<sup>®</sup>, UNIX<sup>®</sup> and Windows<sup>®</sup></span></td>
<td valign="top" width="31.63265306122449%" headers="d0e79 ">32 KB</td>
<td valign="top" width="42.857142857142854%" headers="d0e81 ">64 KB</td>
</tr>
</tbody>
</table>
</div>
In the latest level of Distributed
Relational Database Architecture™ (DRDA<sup>®</sup>), the server can choose to operate
in a mode in which it is not limited to a fixed query block size in returning
result sets.</div>
</li>
<li>The cursor is defined as scrollable and a block cursor is not used in
the application.</li>
</ul>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rbal1facblk.htm" title="A very important performance factor is whether blocking occurs when data is transferred between the application requester (AR) and the application server (AS). A group of rows transmitted as a block of data requires much less communications overhead than the same data sent one row at a time.">Factors that affect blocking for DRDA</a></div>
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