The presence of a case expression in the original query syntax does not cause the query optimizer to reject quickpass mode.
The presence of a case expression in the original query syntax will not cause the query optimizer to reject quickpass mode.
The ability to handle case expressions is not set for servers in this class. When a SQL statement containing a case expression is optimized, the presence of the case expression causes the Component Integration Services quickpass optimization to reject the statement. When this happens, the case expression must be evaluated by the local Adaptive Server after retrieving data from the remote server.
The ability to handle case expressions is determined by the result set from the RPC sp_capabilities. If direct_connect indicates that it can handle case expressions, then Component Integration Services forwards them to the direct_connect when quickpass mode is used to handle the query.
case in the Reference Manual.
