Full-Text Search Architecture
The Microsoft Full-Text Engine for SQL Server (MSFTESQL) powers full-text search in SQL Server. This engine is in turn built on Microsoft Search (MSSearch) technology and is integrated into the SQL Server 2005 Database Engine more tightly than ever. One major architectural improvement made in the SQL Server 2005 release has been the implementation of side-by-side installs of the full-text engine. This means that for each instance of SQL Server 2005, there is a dedicated instance of MSFTESQL, including dedicated components (such as word breakers and filters), resources (such as memory), and configuration (such as service-level settings like resource_usage) at the instance level.
(The full-text search engine in previous versions of SQL Server was shared by all instances of SQL Server, as well as the operating system and other Microsoft server products such as Exchange and SharePoint™ Portal Server. A side effect of this approach was that updates to the operating system or other products that used MSSearch had wide and sometimes undesired effects on all other products that used MSSearch.)
Let's take a closer look at SQL Server 2005 full-text search.