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DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

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method. Prior to <strong>DB2</strong> V8 those array fetch and insert requests only affect the processing<br />

between the application program and the <strong>DB2</strong> CLI/ODBC Driver on the workstation.<br />

<strong>DB2</strong> V8 introduces multi-row fetch and insert. This function is by default enabled <strong>for</strong> DRDA<br />

requests and client application array requests. In Figure 7-1 we show how the usage of<br />

multi-row operations saves cross-memory trips between the distributed address space and<br />

the database engine. This improvement can significantly reduce elapsed time and CPU cost<br />

on the server.<br />

Connect<br />

Prepare<br />

Open<br />

Cursor<br />

Fetches<br />

Close<br />

Cursor<br />

Commit<br />

Figure 7-1 Multi-row FETCH distributed <strong>DB2</strong> V7 vs. <strong>DB2</strong> V8<br />

Multi-row in DRDA becomes already active in CM <strong>for</strong> client CLI/ODBC and host to host SQL<br />

requests.<br />

In the following sections the per<strong>for</strong>mance of multi-row FETCH and INSERT is evaluated.<br />

7.2.1 Per<strong>for</strong>mance - Distributed host to host<br />

In this section we present the per<strong>for</strong>mance measurements in a distributed host to host<br />

environment.<br />

Per<strong>for</strong>mance measurements description<br />

In these measurements we used:<br />

► <strong>DB2</strong> <strong>for</strong> z/<strong>OS</strong>, V7 and V8<br />

► z/<strong>OS</strong> Release 1.3<br />

286 <strong>DB2</strong> <strong>UDB</strong> <strong>for</strong> z/<strong>OS</strong> <strong>Version</strong> 8 Per<strong>for</strong>mance <strong>Topics</strong><br />

Multi-row fetch distributed be<strong>for</strong>e V8 vs. V8<br />

DIST DBM1 MSTR IRLM<br />

Connect<br />

Prepare<br />

Open<br />

Cursor<br />

Close<br />

Cursor<br />

Commit<br />

Fetch<br />

rowset<br />

DIST DBM1 MSTR IRLM

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