Create Index vs. Auto Create Statistics
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hi all,
When using the 'auto create statistics (default)', SS2k creates statistics and creates indexes named _WA_SYS_....
Can you interpret these indexes (i.e., _WA_SYS) as a 'hint' from SS2k? By 'hint', I am implying that since an index created with a 'CREATE INDEX (..) ON (...)' statement does not exist, should I consider creating an index on this column.
Assuming you do update statistics on table/indexes, is a there a performance advantage by using a 'CREATE INDEX' vs 'Auto Create Statistics index'?
Thanks.
Steve
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- _WA** are just statistics, that 's not the same as a regular index.
- However it does give you a hint on which columns are used for searchoperations.
- Use "create index wizard" if you want to examin which indexes may be usefull. (better is to be DBA-part of the development-team so you get a realy good view on which access is needed, how they tend to implement it and maybe even you may be alowed to give optimization tips for their code, sql and sqlserver access)
Johan
Learn to play, play to learn !Dont drive faster than your guardian angel can fly ...
but keeping both feet on the ground wont get you anywhere :w00t:- How to post Performance Problems
- How to post data/code to get the best help[/url]- How to prevent a sore throat after hours of presenting ppt
press F1 for solution, press shift+F1 for urgent solution 😀
Need a bit of Powershell? How about this
Who am I ? Sometimes this is me but most of the time this is me
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Does anybody have a handy script that will identify search fields for the _WA** indexes?
Terry -
based on system catalog info (designed for sql2k sp3)
select u.name as TbOwner, o.name as TbName , x.name as IxName, xc.name as IxColName, xk.keyno as KeyOrder
from sysobjects o
inner join sysindexes x
on o.id = x.id
inner join sysindexkeys xk
on x.id = xk.id
and x.indid = xk.indid
inner join syscolumns xc
on o.id = xc.id
and xk.colid = xc.colid
inner join sysusers u
on u.uid = o.uid
where o.xtype = 'u'
and keys is not null
and x.name like '_w%'
order by o.name, x.name, xk.keyno
TEST IT
Johan
Learn to play, play to learn !Dont drive faster than your guardian angel can fly ...
but keeping both feet on the ground wont get you anywhere :w00t:- How to post Performance Problems
- How to post data/code to get the best help[/url]- How to prevent a sore throat after hours of presenting ppt
press F1 for solution, press shift+F1 for urgent solution 😀
Need a bit of Powershell? How about this
Who am I ? Sometimes this is me but most of the time this is me
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