Determining an Optimimum Fetch Size
In the Read from DB stage, the optimum fetch size is calculated by taking execution time readings between a Read from DB stage and a Write to Null stage.
- Create a job in the Spectrum Enterprise Designer.
- Drag a Read from DB stage to the canvas.
- Drag a Write to Null stage to the canvas.
- Create a channel between the two stages.
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Double-click on the Read from DB stage to configure it
to read data from a table containing the test data.
- Save the job.
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Run the job.
The Execution Details window opens.
- Click Refresh.
- Note the Started and Finished times.
- Repeat the steps 7 - 9, gradually increasing the fetch size to identify the optimal setting for your server.
You now have identified the fetch size setting that provides the optimal performance for your environment.
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