Search 2010 Capabilities

1. SP foundation Search: can only crawl sharepoint sites within the farm
2. Search Server 2010 and SP foundation can index and search up to 300,000 items if they use SQL Express; otherwise they can index and search up to 10 million items if they use full version of SQL Server
3. A Scale out Search server 2010/Sharepoint Server 2010 farm can index and search up to 100 million items
4. A FAST Search server 2010 can support extreme scale, and can index and search over a billion items

Achieve: Delivering sub-second latency for all searches
No query server deals with more than ten millions items;you can achieve this by adding multiple query servers to the farm ,and taking advantage of new index partitioning feature of SP 2010.Index partitioning enables administrators to spread the load for queries across the multiple servers.

Wildcard Search
"comp*" - would find the document that contain "Computers" or "Component" or "competency"
"author:ad*"- would find the documents created by "Admin" or "Adam"
"comp* author:ad*" - would find the documents that contain "component" and created by "admin"

This can be achieved by creating subsets of an index, and propagating individual subsets to different query servers.SP2010 uses the hash of each document's ID determine in which partition the index entries for a specific document should be stored. At query time , the query object model contact the each query server needed to satisfy the search so that all results to be returned to the user are included.