Microsoft® SQL Server 2008 R2 Unleashed

Evaluating Page Compression

Before choosing to implement page compression, you should determine if the overhead of page compression will provide sufficient benefit in space savings. To determine how changing the compression state will affect a table or an index, you can use the SQL Server 2008 sp_estimate_data_compression_savings stored procedure, which is available only in the editions of SQL Server that support data compression. This stored procedure evaluates the effects of compression by sampling up to 5,000 pages in the table and creating a copy of these 5,000 pages of the table in tempdb, performing the compression, and then using the sample to estimate the overall size for the table after compression. The syntax for sp_estimate_data_compression_savings ...