Manifold Spatial Extender for SQL Server

The Manifold Spatial Extender for SQL Server is a free extension module for SQL Server which provides spatial index functionality for Manifold System. Manifold Spatial Extender works with all versions of SQL Server starting with SQL Server 2005. Using Manifold Spatial Extender on SQL Server 2005 Express requires SQL Server 2005 Express SP2. The extender operates via the use of the common language runtime (CLR) integration feature of SQL Server

Download the Manifold Spatial Extender from links in the Manifold Updates page at http://www.manifold.net/updates or from other links on the manifold.net web site. The download provides the extender and a small installation utility to simplify installation of the extension and configuration of SQL Server.

The utility installs on the machine on which SQL Server runs. It works as an extension to SQL Server to provide more effective management of spatial indices using SQL Server resources. It does not provide built-in spatial operators to SQL Server or otherwise give SQL Server the ability to function as a spatial DBMS if Manifold is not used as a client.

The spatial extender automatically works together with Manifold as a client when Manifold connects to SQL Server via OLE DB. Manifold will automatically recognize the presence of the spatial extender and will use it to create and manage spatial indices when drawings are exported to SQL Server.

Exporting a drawing using a Manifold drawing type with the geometry type set to Geometry or Geometry (WKB) to an instance of SQL Server with the Manifold spatial extender installed creates a server-side index managed by the extender. Using a server-side index provides for slightly better performance on reads, significantly better performance on writes, and makes writes more robust. The spatial extender also allows SQL Server to operate more efficiently in a spatial server / Manifold client relationship, so it lowers load on the server as well.

The Manifold spatial extender is a free utility made available to Manifold System licensees at no charge. It is nonetheless licensed software that is covered by the Manifold EULA. You may install it on as many machines as you like so long as your intent is to use it primarily with Manifold System.

The purpose of the spatial extender is to give SQL Server 2005 users the fastest possible spatial indices when used with Manifold System. This will allow users committed to SQL Server to get started today with speedy spatial technology in a way that will in the future allow easy migration to SQL Server 2008 and will (hopefully) help avoid fragmentation of the pre-2008 SQL Server user base into many different, incompatible spatial extenders that collectively will be difficult to migrate to SQL Server 2008.

Note that there are two similar but significantly different Manifold approaches to providing spatial indices for SQL Server that are managed by Manifold (as opposed to using built-in Microsoft spatial facilities as are provided in SQL Server 2008 spatial). The first is using generic spatial indices as can be done with almost any DBMS. The second is installing the Manifold spatial extender in SQL Server and then using spatial indices managed by the spatial extender.

Both can even be used at the same time, although that would be a rare and unusual situation since the spatial extender swings into action automatically with Manifold once it is installed. However, if we began work with, say, SQL Server 2005 using generic spatial indices and then later on installed the spatial extender and uploaded some more drawings, in that case Manifold would use either the generic spatial index originally created or the new spatial index managed by spatial extender as the case may be for individual drawings. To avoid any guesswork as to what spatial index is being used it is strongly recommended that the spatial extender be installed on SQL Server 2005 installations and used from the beginning for all Manifold work.

As a practical matter, the spatial extender improves performance so much that it should always be used in SQL Server 2005 installations in preference to using generic spatial indices without the spatial extender. The manifold.net team knows of no disadvantage to using it. It is small, robust, very fast, perfectly integrated with Manifold and, of course, free of charge.

The spatial extender can work with Manifold drawings uploaded using either Manifold Geometry or OGC Geometry (WKB) geometry types. because Manifold Geometry is a higher performance and more robust type than OGC Geometry (WKB), if direct interoperability with WKB applications is not a requirement then Manifold Geometry should always be used as the geometry type.