ASA SQL User's Guide
Accessing Remote Data
Internal operations
The most efficient way to handle a statement is usually to hand as much of the original statement as possible off to the remote server involved. Adaptive Server Anywhere will attempt to pass off as much of the statement as is possible. In many cases this will be the complete statement as originally given to Adaptive Server Anywhere.
Adaptive Server Anywhere will hand off the complete statement when:
Every table in the statement resides in the same remote server.
The remote server is capable of processing all of the syntax in the statement.
In rare conditions, it may actually be more efficient to let Adaptive Server Anywhere do some of the work instead of passing it off. For example, Adaptive Server Anywhere may have a better sorting algorithm. In this case you may consider altering the capabilities of a remote server using the ALTER SERVER statement.
For more information, see ALTER SERVER statement.