Query Performance Question

I have a query that takes approximately 2 mins to run. The query is derived from two tables that have a one to many relationship. When I comment out 4 of the fields in the 'select' portion of the query, it speeds up to 18 seconds. I know that I am doin
g a bookmark lookup (this is 60% of the query time) but I am not sure how to avoid this. Any ideas?
Hi,
The covering index is only effective when the query
does a Bookmark lookup. if you have covering index the query will not hit
the source table for data. but , the disadvantage is that a covering index
increases the
number of writes when one or more of the columns in the index is updated.
This might be a issue durng insert./update and delete.
Thanks
Hari
MCDBA
"Daniel Avsec" <Daniel Avsec@.discussions.microsoft.com> wrote in message
news:1611776E-29E8-4F46-BB8F-97A8E6A32C45@.microsoft.com...
> I have a query that takes approximately 2 mins to run. The query is
derived from two tables that have a one to many relationship. When I
comment out 4 of the fields in the 'select' portion of the query, it speeds
up to 18 seconds. I know that I am doing a bookmark lookup (this is 60% of
the query time) but I am not sure how to avoid this. Any ideas?

Query Performance Question

I have a query that takes approximately 2 mins to run. The query is derived from two tables that have a one to many relationship. When I comment out 4 of the fields in the 'select' portion of the query, it speeds up to 18 seconds. I know that I am doing a bookmark lookup (this is 60% of the query time) but I am not sure how to avoid this. Any ideas?Hi,
The covering index is only effective when the query
does a Bookmark lookup. if you have covering index the query will not hit
the source table for data. but , the disadvantage is that a covering index
increases the
number of writes when one or more of the columns in the index is updated.
This might be a issue durng insert./update and delete.
Thanks
Hari
MCDBA
"Daniel Avsec" <Daniel Avsec@.discussions.microsoft.com> wrote in message
news:1611776E-29E8-4F46-BB8F-97A8E6A32C45@.microsoft.com...
> I have a query that takes approximately 2 mins to run. The query is
derived from two tables that have a one to many relationship. When I
comment out 4 of the fields in the 'select' portion of the query, it speeds
up to 18 seconds. I know that I am doing a bookmark lookup (this is 60% of
the query time) but I am not sure how to avoid this. Any ideas?

Query Performance Question

I have a query that takes approximately 2 mins to run. The query is derived
from two tables that have a one to many relationship. When I comment out 4
of the fields in the 'select' portion of the query, it speeds up to 18 seco
nds. I know that I am doin
g a bookmark lookup (this is 60% of the query time) but I am not sure how to
avoid this. Any ideas?Hi,
The covering index is only effective when the query
does a Bookmark lookup. if you have covering index the query will not hit
the source table for data. but , the disadvantage is that a covering index
increases the
number of writes when one or more of the columns in the index is updated.
This might be a issue durng insert./update and delete.
Thanks
Hari
MCDBA
"Daniel Avsec" <Daniel Avsec@.discussions.microsoft.com> wrote in message
news:1611776E-29E8-4F46-BB8F-97A8E6A32C45@.microsoft.com...
> I have a query that takes approximately 2 mins to run. The query is
derived from two tables that have a one to many relationship. When I
comment out 4 of the fields in the 'select' portion of the query, it speeds
up to 18 seconds. I know that I am doing a bookmark lookup (this is 60% of
the query time) but I am not sure how to avoid this. Any ideas?sql