Hi Bill,

>This probably isn't a Rushmore problem after all.

Exactly. What your query has to do is to read any record in table 1 and seek it in table 2. You are not limiting the result set and therefore Rushmore can't jump in. Eventually it might even be faster to avoid Rushmore at all here and use a pure Xbase solution. In other words, open both tables, set a relation from table 1 into table 2 and then do a SCAN FOR EOF("Table2") to find all records in table 1 that have no corresponding record in table 2.

The speed issue you are seeing is caused by caching. After you executed the query the first time, VFP read everything into the cache. Running the same query a second time fetches all information from memory and not from the hard disk. By switching to a different application, you tell VFP to switch to using the background buffer and discard cached information that do not fit into it. This is controlled by the SYS(3050) function.

Christof