Checking Statistics Validity

Bob Dorr has scripts to tell if your statistics are accurate:

The dilemma we all run into is what level of SAMPLED statistics is appropriate?   The answer is you have to test but that is not always feasible and in the case of Microsoft CSS we generally don’t have histogram, historical states to revisit.

Microsoft CSS is engaged to help track down the source of a poorly performing query.   It is common step to locate possible cardinality mismatches and study them closer.   Studying the statistics dates, row modification counter(s), atypical parameters usage and the like are among the fundamental troubleshooting steps.

Good post and great scripts, even if he Microsoftly nouns the verb “ask.”

Related Posts

Errors Updating Stats on Columnstore Indexes

Max Vernon walks us through some problems trying to update statistics on columnstore indexes: The first error above would be seen if you have a SQL Server Agent job that updates statistics. The second error is how it looks in an SSMS Query window. The error message claims that UPDATE STATISTICS can only be used on a […]

Read More

Defining Downtime Down

Andy Mallon takes us through the notion of downtime: There’s a lot of discussion about preventing downtime. As a DBA and IT professional, it’s my sworn duty to prevent downtime. I usually describe my job as DBA something along the lines of, “to make sure data is always available to the people and applications that […]

Read More

Categories

November 2015
MTWTFSS
« Jan Dec »
 1
2345678
9101112131415
16171819202122
23242526272829
30