During SQL Server 2005 development I did a comprehensive rewrite of the Books Online entries concerned with estimating index, table, and database size (see http://msdn2.microsoft.com/en-us/library/ms187445.aspx). I was recently having a discussion with Øystein Sundsbø about a bug in one of the formulas I wrote and it turns out he’s written a neat tool that codifies all the formulas. In case you’re interested, the part of the formula I had incorrect was for figuring out how many pages would be needed for the upper levels of an index b-tree. My formula was: Num_Index_Pages = ∑Level (Index_Rows_Per_Page)Level – 1 and Øystein came up with a better formula: Num_Index_Pages = ∑Level (Total_Num_Rows/(Index_Rows_Per_Page)Level ) where in both formulas: Levels = 1 + log Index_Rows_Per_Page (Total_Num_Rows / Index_Rows_Per_Page) Check out Øystein’s cool tool at http://dbgoby.blogspot.com/2007/10/db-goby-v10.html!
where 1 <= Level <= Levels
where 1 <= Level <= Levels
Paul S. Randal
In Recovery...
One Response to Tool for estimating the size of a database
[...] Estimating the Size of Heaps, Clustered Indexes, and Nonclustered Indexes and in the blog post Tool for estimating the size of a database I link to a tool someone put together that codified all my formulas. You can also get sizing [...]