June 7, 2010 at 5:04 am
IS there any relation between fragmented and low statistics data ? means of statistics goes out of dated, does it impact fragmentation also ?
-------Bhuvnesh----------
I work only to learn Sql Server...though my company pays me for getting their stuff done;-)
June 7, 2010 at 5:20 am
No
Other than that an index rebuild will update statistics, they're completely unrelated.
Fragmentation is related to the physical and logical ordering of the pages of an index within the data file
Statistics are summary data that are kept for columns within a table that allow the optimiser to estimate cardinality for query predicates.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
June 7, 2010 at 5:50 am
GilaMonster (6/7/2010)
Fragmentation is related to the physical and logical ordering of the pages of an index within the data file
yes got the point but whenever we have DML operations it disturbs the ordering of data which also leads to statistics out dation
-------Bhuvnesh----------
I work only to learn Sql Server...though my company pays me for getting their stuff done;-)
June 7, 2010 at 6:05 am
Some DML operations can cause fragmentation. Deletes will never, updates and inserts may, depending what they do.
Some DML operations can make statistics outdated, depending what they do.
It's trivially possible to have a scenario where a certain table never gets fragmented, but where the statistics get outdated so fast that the auto update doesn't keep up. Vis versa is also completely possible.
They are unrelated concepts, you need to understand what both are and not worry about how they're linked.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
June 7, 2010 at 6:16 am
GilaMonster (6/7/2010)
you need to understand what both are and not worry about how they're linked.
that is golden point ...thanks 🙂
-------Bhuvnesh----------
I work only to learn Sql Server...though my company pays me for getting their stuff done;-)
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