SQL Server Performance Forum – Threads Archive

Statistics Sampling percentage…

Where do we get the sampling percentage apart from the "rows sampled" field from DBCC show_statistics? when i query one of my tables, it shows 41359 rows sampled from 1801711 rows. does this mean the sampling percent is 2.30%? Thanks,
Ram "It is easy to write code for a spec and walk in water, provided, both are freezed…"

Stats available are the number of rows in the table and the number of rows sampled. The number of sample values average key length, the index densities (distinct range rows, and average range rows), and sampled value are the other characteristics of stats. Key density is the reciprocal of the count of distinct key values in the tables. The smaller the key density, the more effective the index is likely to be. SQL Server#%92s query optimizer uses these statistics to determine which indexes to use when executing a query. Satya SKJ
Microsoft SQL Server MVP
Contributing Editor & Forums Moderator
http://www.SQL-Server-Performance.Com
This posting is provided AS IS with no rights for the sake of knowledge sharing.

So, how do we get to know the sampling percentage for a table? Thanks,
Ram "It is easy to write code for a spec and walk in water, provided, both are freezed…"

http://www.microsoft.com/technet/prodtechnol/sql/2005/qrystats.mspx fyi. Satya SKJ
Microsoft SQL Server MVP
Contributing Editor & Forums Moderator
http://www.SQL-Server-Performance.Com
This posting is provided AS IS with no rights for the sake of knowledge sharing.

Its my mistake. it should be posted in SQL Server 2000 General DBA Questions. got confused due to the new change. Thanks,
Ram "It is easy to write code for a spec and walk in water, provided, both are freezed…"

No issues, I appreciate your feedback for stating the version. Satya SKJ
Microsoft SQL Server MVP
Contributing Editor & Forums Moderator
http://www.SQL-Server-Performance.Com
This posting is provided AS IS with no rights for the sake of knowledge sharing.

]]>