Improve SQL statement caching for SQL Server

WTSupported in traditional Synergy on Windows
WNSupported in Synergy .NET on Windows



The SQLPERFORMANCESQL environment variable causes SQL Connection to use SQLDescribeParam internally to improve performance for SQL statements with I/O parameters when accessing SQL Server.


Any value.


Set this environment variable to any value to improve performance and avoid excessive cache memory thrashing for SQL statements with I/O parameters when accessing SQL Server (VTX12_SQLNATIVE). When this is set, SQL Connection calls the ODBC API function SQLDescribeParam internally for all SQL Server cursors. (For an option that invokes this functionality only for cursors opened on a specified database channel, see SSQL_PERFORMANCE_SQL.)


This feature will work for a stored procedure only if the case of column names in the SQL statement matches the case of column names in the database. (This is a SQLDescribeParam limitation.) If inconsistent case prevents this feature from working, an %SSC_EXEC failure on SQLDescribeParam is written to the SSQLLOG file. See SQL Connection logging for information on SSQLLOG logging.

Setting location

The environment or synergy.ini. For client/server configurations, set SQLPERFORMANCESQL on the client.

Used by

SQL Connection