You can control aspects of DataServer query handling not only programmatically within ABL statements, but also through startup and connection parameter options as described in this section.
Note: Startup and connection parameters override query-tuning defaults. However, options set in the QUERY-TUNING phrase take precedence over startup and connection parameters. For example, if you specify NO-DEBUG for a query within your application, specifying qt_debug,SQL at connection time overrides the default application behavior but does not override the NO-DEBUG option that you specified for the query. See Query tuning for more information.
The following table describes the query-tuning options that you can specify with the -Dsrv parameter.
For more detailed descriptions of these options, see Using qt_debug to Analyze Performance. For information on Enhanced Logger options that replace the qt_debug options, see Analyzing application execution with Enhanced Logger.
Specify qt_no_lookahead for query behavior that is consistent with an OpenEdge database.
Specifies whether each cursor should use a separate connection to the MS SQL Server database. The default is qt_no_separate_connection, which provides behavior that is consistent with an OpenEdge database. Specify qt_separate_connection to use a separate connection. Executing cursors in separate connections can improve performance because the DataServer does not have to restart the cursors.
Specifies the size in bytes of the cache used by lookahead cursors. A larger cache size can improve performance for queries that return a large number of records because the DataServer might need fewer SQL statements to get the results.
Minimum: The DataServer always caches at least one record.
Default: 10,000 when block cursors are enabled (the default). 30,000 when block cursors are disabled.
CONNECT holder -db infdb-dt MSS -ld demo -U user -P password -Dsrv qt_separate_connection,qt_debug,EXTENDED.
OpenEdge provides a startup parameter called Server Join (-nojoinbysqldb) that controls the default JOIN-BY-SQLDB behavior. You specify this parameter in the startup command for your OpenEdge session. It overrides the JOIN-BY-SQLDB default so that the client evaluates and performs joins. Using this parameter might slow performance, but it provides results that are consistent with queries run against an OpenEdge database. See Initial Programming Considerations for more information.