A client can also impose a time limit that it is willing to wait for a server to return the result set. The value of the search time out property specifies this limit. When the server fails to respond to a query within the specified time period, the client can abandon the search and try again later.
The time-out property is useful when a client requests an asynchronous search. In an asynchronous search, the client makes a request and then proceeds with other tasks while waiting for the server to return the results. It is possible that the server can go offline without notifying the client. In this case, the client has no way of knowing whether the server is still processing the query, or if it has ceased to be live. The time-out property gives the client some control of situations like this.