Indexing Service is no longer supported as of Windows XP and is unavailable for use as of Windows 8. Instead, use Windows Search for client side search and Microsoft Search Server Express for server side search.
The MaxRestrictionNodes entry is the maximum number of query restriction nodes that can be created by Indexing Service in a single query.
|Range:||1 - 4294967295 (0xFFFFFFFF)|
If query normalization creates a query restriction that is greater than the value of the MaxRestrictionNodes entry, the query fails with the status of QUERY_E_TOOCOMPLEX. This status message means the query was too complex to be completed because it surpassed the limit imposed in this registry key. The value of this entry keeps a user from overloading the capacity of the server with a complex query.