Once a collection is created, it is ready to receive data for indexing from the enqueueing functions. These functions will automatically start the crawler service if necessary. The crawler service is the service that retrieves data from specific URLs, and processes that data so that it can be indexed.
If the error attribute is set on any crawler-service-enqueue-response node that is returned by any of these functions, an exception will be raised regardless of the value of the exception-on-failure parameter. The error attribute is set for enqueue operations that fail due to problems communicating with the crawler, the internal state of the crawler, or because of invalid XML content. See Handling Enqueueing Errors for more information.