Saturday, February 25, 2012

Perfomance issue

Looking for suggestions about what I might look for..
During periods of time when no INSERTS are taking place, SELECT statement
durations are around 16-30ms for hundreds of requests per minute.
When there is a batch of INSERTS that are sent to the table via SP that
number in the many thousands..for a while both INSERTS and SELECTS coexist at
around the same duration of 16-30 ms..watching this with Profiler.
Then, for some reason..some SELECT and few INSERTS will go up to the 4000 -
5000 ms range. Then things will quiet down, then go back up to 4000ms. These
don't have to be on the same table and frequently are not...INSERTS are going
to 1 table while the majority are going to another table in the same DB. This
happens on all the servers we have so it's not specific to one server. They
all have the same hardware and software.
I've looked for deadlocks and there are none. I've set some of the common
things in PERFMON such as CACHE BUFFER HIT RATIO. Looks ok. There's 4GB of
RAM on the server and there's 1GB available.
The MDF has it's own separate drive and the LDF has it's own drive.
It's almost looks like theres some sort of contention between the INSERT and
the SELECT, but since it's in separate tables...i have no idea what to look
for.
any help appreciated.
The servers were recently upgraded from SQL 7 .. I'm not sure if this was
happening under SQL 7. I don't think so. I've updated statistics on all
servers and recreated the clustered indexes.
SQL 2000 with SP4.
thanks,
DonTry updating stats with FULLSCAN. Also, trace the Lock Escalation event.
--
Tom
----
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA
SQL Server MVP
Columnist, SQL Server Professional
Toronto, ON Canada
www.pinpub.com
.
"donsql22222" <donsql22222@.discussions.microsoft.com> wrote in message
news:776E5217-2EDB-40FF-BFA6-E8A3E1ADF980@.microsoft.com...
Looking for suggestions about what I might look for..
During periods of time when no INSERTS are taking place, SELECT statement
durations are around 16-30ms for hundreds of requests per minute.
When there is a batch of INSERTS that are sent to the table via SP that
number in the many thousands..for a while both INSERTS and SELECTS coexist
at
around the same duration of 16-30 ms..watching this with Profiler.
Then, for some reason..some SELECT and few INSERTS will go up to the 4000 -
5000 ms range. Then things will quiet down, then go back up to 4000ms. These
don't have to be on the same table and frequently are not...INSERTS are
going
to 1 table while the majority are going to another table in the same DB.
This
happens on all the servers we have so it's not specific to one server. They
all have the same hardware and software.
I've looked for deadlocks and there are none. I've set some of the common
things in PERFMON such as CACHE BUFFER HIT RATIO. Looks ok. There's 4GB of
RAM on the server and there's 1GB available.
The MDF has it's own separate drive and the LDF has it's own drive.
It's almost looks like theres some sort of contention between the INSERT and
the SELECT, but since it's in separate tables...i have no idea what to look
for.
any help appreciated.
The servers were recently upgraded from SQL 7 .. I'm not sure if this was
happening under SQL 7. I don't think so. I've updated statistics on all
servers and recreated the clustered indexes.
SQL 2000 with SP4.
thanks,
Don|||On Mon, 13 Feb 2006 16:38:26 -0800, "donsql22222"
<donsql22222@.discussions.microsoft.com> wrote:
>It's almost looks like theres some sort of contention between the INSERT and
>the SELECT, but since it's in separate tables...i have no idea what to look
>for.
Of course there's contention, for LRU pages in memory, the moreso
because they are different tables!
Run the queries during the slow period from QA with SET STATISTICS IO
ON, and look at the physical reads numbers going from 0 to whatever.
J.

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