Search Engine Configuration and Management

The Content Store's search functionality is provided by Apache Solr, a Java-based open source search engine that runs as a standalone web application in its own application server. A copy of Solr used to be bundled with older versions of the Content Store, but due to changes in Solr this is no longer the case. The CUE Content Store Installation Guide includes a description of how to install Solr for use with the Content Store. A solr instance must be deployed alongside every Content Store you deploy. All CUE search functions depend on Solr, and Solr can also be used to drive the search functions in your publication web applications.

The use of an external search engine that is completely decoupled from the Content Store ensures a high degree of flexibility. It is possible to configure the search engine and the other components involved in providing search functions in many different ways to meet differing requirements. The components involved in providing the Content Store's search functions are:

indexer web services

Two indexer web services are provided by the Content Store for logging changes to content managed by the Content Store. The indexer web services are called:


This web service helps to maintain the internal index used by CUE and other editorial systems. Every time any content item is added, modified or deleted, it adds an entry to its change log. The entry contains the URIs of the documents affected by the change.


This web service helps to maintain the external index used by the presentation system. It works in exactly the same way as index except that it does not log updates to staged content items, since staged content items (unpublished revisions of published content items) should not be visible to web site visitors.

indexer web application

An indexer web application runs inside an application server. Every five seconds, it submits a requests to one of the indexer web services and obtains the URIs of the documents that have changed in the last 5 seconds. It then submits requests to the Content Store for these documents, passes them through an XSL filter to prepare them for indexing and posts the results to solr.


solr runs inside its own application server. It generates and maintains an index based on the documents submitted by its indexer. It also responds to any search requests submitted to it, either from CUE clients or from publication web applications.