Progress
Version 9
Product Update Bulletin
Progress Version 9.1C DataServer For Microsoft SQL Server
The Progress Version 9.1C DataServer for Microsoft SQL Server had enhancements and new features of which the following -Dsrv startup parameters are documented here.
Query Result Order: The PRGRS_ALWAYS_INDEX Option
The default value for the PRGRS_ALWAYS_INDEX option is 1 or ON. For the Microsoft SQL Server DataServer, if MSS_PRESERVER_CURS is set to 1, then PRGRS_ALWAYS_INDEX can be set to zero. If MSS_PRESERVE_CURS is set to 0, then the PRGRS_ALWAYS_INDEX setting is ignored.
Some queries can gain a performance advantage when the result set from the query does not use an index to order the results. In older versions of the DataServer for Microsoft SQL Server, results sets were always indexed because queries and their results were gathered in segments with new cursors being generated for each query segment. However, most advanced drivers and data sources now allow a single cursor to be retained for the life of a given query, even across a transaction boundary. Drivers that can preserve cursors are allowed to execute unindexed queries if the PRGRS_ALWAYS_INDEX option is set to 0 (off). When this option is off and the user does not specify an index or BY clause for the results of their 4GL statement and the particular 4GL being executed does not require scrolling capability in the Progress client, the query result will remain unindexed by the DataServer.
NOTE: In an unindexed query, the DataServer will not send an ORDER BY clause to the data source. Regardless of whether or not an ORDER BY clause is used, the DataServer has no control over the index utilized by the data source.Preserve Cursors: The MSS_PRESERVE_CURS,1 Option
The default value for the MSS_PRESERVE_CURS option is 0 or OFF.
The MMS_PRESERVERE_CURS,1 -Dsrv startup option allows server side cursors in Microsoft SQL Server to be preserved beyond a transaction boundary. Under many circumstances, preserved cursors can result in a significant performance improvement. However, in some instances, degradation has also been experienced as the result of this setting, so the default value for the -Dsrv switch toggle is off. If you want to turn it on to see if performance benefits are available to you through this setting, enter the following -Dsrv option:
-Dsrv MSS_PROSERVE_CURS,1.
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