Indexes :-

hi,
one small ques on indexes, i added one composite index on table to avoud clus index scan(cost 70%) , when i checked executioin plan it is showing me like clus index seek using the above defined index + bookmark lookup operator also..
so which soln should i go for clus index scan or bookmark operator using clus index seek (for composit index0
Sanju
Run the query both ways in Query Analyzer and look at the Total Plan cost
.... use whichever is cheaper..
I suspect if you are returning more than (maybe) 5% of the rows in the table
the clustered index scan might be cheaper...
However it does depend on the percentage of the rows returned, a single or
very small number of rows returned will likely be best served by the
nonclust and bookmark lookup, a larger percentage of rows and the clustered
index scan will be faster...
Wayne Snyder, MCDBA, SQL Server MVP
Mariner, Charlotte, NC
www.mariner-usa.com
(Please respond only to the newsgroups.)
I support the Professional Association of SQL Server (PASS) and it's
community of SQL Server professionals.
www.sqlpass.org
"Sanjay" <Sanjay@.discussions.microsoft.com> wrote in message
news:B0F41810-3BC3-4D2C-9996-7D08C46F614D@.microsoft.com...
> hi,
> one small ques on indexes, i added one composite index on table to avoud
clus index scan(cost 70%) , when i checked executioin plan it is showing me
like clus index seek using the above defined index + bookmark lookup
operator also..
> so which soln should i go for clus index scan or bookmark operator using
clus index seek (for composit index0
> --
> Sanju