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15 August,2012 by Jack Vamvas
Question: Usually when I look at the statistics information on an index , SQL statistics are available. I was troubleshooting a query performance issue today – and noticed no statistics under heavily used objects. What could be causing this problem, as I understand the DB engine maintains the statistics about the key value distribution, and uses the statistics for query plan compilation.?
Answer: Check the status of AUTO CREATE STATISTICS. If it’s OFF , then most likely someone has turned it off. When AUTO CREATE STATISTICS is set at OFF , a manual process must be set up to create statistics.
Normally I have AUTO CREATE STATISTICS at ON. This means the SQL Query Optimizer creates the statistics on individual columns for cardinality improvement.
Read Also
SQL Server Query Optimizer and Statistics
Filtered statistics, T-SQL best practises for T-SQL Tuesday
Author: Jack Vamvas (http://www.sqlserver-dba.com)
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