In a multisite environment, you associate specific sites with specific content sets as a way of constraining indexing and querying. For example, suppose you have three sites, A, B, and C, and a content set that you want to make available for searching on sites A and C, but not on site B. To do this, you could associate sites A and C with this content set in Site Administration. When the index is generated, the logical partition associated with this content set does not include data for site B.

When a query is issued, rather than directing it to all of the logical partitions of the index, Routing looks at the sites the query applies to, determines which content sets are associated with those sites, and directs the query only to the partitions for those content sets. So in this example, if a customer is searching site B, Routing will not direct the query to the logical partition for this content set. This restriction makes searching more efficient, because it reduces the number of logical partitions that need to be searched.

There may be times when you do not want to return data for a specific site, even though that data is included in the index. For example, if a site is disabled or otherwise unavailable, it is generally undesirable to return search results for that site. Therefore, Oracle ATG Web Commerce Search does not return results for sites that are currently unavailable.