I'm connecting from Oracle to different databases (MS Access, MySQL, ...). When opening the connection, the metadata (table and view definitions) from remote database is read by Oracle. But when updating a remote object metadata (add column on table, view definition,...) Oracle is not noticed.
The only way I've found to refresh the metadata is to kill the heterogeneous server process (hsolesql, ...) and query again. There is any other way to do it without killing the process?
Perhaps by changing the HS_DESCRIBE_CACHE_HWM initialization parameter for your gateway to a smaller value (1) it will not continue to cache the data. You'll take a performance hit I believe, but may be necessary if you cannot perform the DDL through the gateway (which should update the cache as well).