Re: ADO.NET query execution much slower than SQL Management Studio
- From: google <zhangleo@xxxxxxxxx>
- Date: Tue, 11 Mar 2008 07:17:30 -0700 (PDT)
On Feb 22, 6:32 pm, "Cowboy \(Gregory A. Beamer\)"
<NoSpamMgbwo...@xxxxxxxxxxxxxxxxxx> wrote:
Definitely.
When you first start using a new database it creates stats. Until created,
the first few queries run slowly, as will any unique type of query, as it
cannot hit stats.
--
Gregory A. Beamer
MVP, MCP: +I, SE, SD, DBA
*************************************************
| Think outside the box!
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*************************************************"dustbort" <d_nospam_bortner@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:uTjHfcYdIHA.3940@xxxxxxxxxxxxxxxxxxxxxxx
Gregory,
Thanks for your ideas. I went to test them and it seems that the problem
has miraculously vanished. I had just copied the production database to
my workstation and updated the stored procedures for testing, prior to
having the slow results. I wonder if the database does some
initialization that had not completed at the time of the first tests?
Something that would affect the .NET SqlClient but not SQL Mgmt Studio?
"Cowboy (Gregory A. Beamer)" <NoSpamMgbwo...@xxxxxxxxxxxxxxxxxx> wrote in
messagenews:u3dE0KYdIHA.2268@xxxxxxxxxxxxxxxxxxxxxxx
Make sure you are testing properly. Run the query twice from ADO.NET and
see if you have a different read time. There are two reasons I can think
of, without much thought, why you might get different read times from #1
to #2.
1. JIT time
2. Stats being compiled on SQL Server
If you find a difference, it may just be preloading your app before use
will solve your issue. If not, here are a variety of things you can look
at:
1. Library used to connect to SQL Server - If you can use In Memory, it
is fastest; none should be overall slow, so this is just shaving a bit of
time, not a full solution
2. ADO.NET library used (ODBC, OLEDB or SQL)
3. Check the indexes
a) Any fragmented indexes need to been recompiled
b) Do you have the right indexes for your query
4. Would adding some locking hints, etc. help your query?
5. Do you need hints for statistics?
6. Can you improve the query? - Look at the execution plan, as it will
give you a lot of information on straightening out your world
If you are dynamically adding statements in a sproc, you will find that
it will end up having to recompile each time and redo its stats. When you
compare this to the profiler command (meaning what is actually run in the
sproc versus running the sproc statement from profiler), you can see a
huge difference in time. This is why you need to make sure you are
running the sproc in each instance and not just the statement. Depending
on how you profile, you might only see the sproc call.
--
Gregory A. Beamer
MVP, MCP: +I, SE, SD, DBA
*************************************************
| Think outside the box! |
*************************************************
"dustbort" <d_nospam_bortner@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
messagenews:%2321JRBYdIHA.4220@xxxxxxxxxxxxxxxxxxxxxxx
I have a stored procedure that when called from SQL 2005 Management
Studio
takes less than one second to execute. The same SP, when called from
.NET
code takes about 13 seconds. I am using a SqlCommand object with
CommandType set to StoredProcedure and I am passing arguments through
the
parameters collection. I have tried using a SqlDataReader and a
DataAdapter
to retrieve the data, but both are equally slow. From stepping thru the
debugger, I know that the specific statement that takes a long time to
execute is either reader.ExecuteReader() or dataAdapter.Fill(dataTable),
equivalently depending on the method I tried. I did a trace in the
Profiler, and got nearly identical result for either method of .NET
SqlClient Data Provider. Here is an example:
EventClass: RPC:Completed
CPU: 13390
Reads: 559475
Writes: 0
Duration: 13496
Binary Data: (a long hex value)
When I copied the TextData (SQL Statement being executed) from Profiler
into
SQL Management Studio, I get the following trace:
EventClass: SQL:BatchCompleted
CPU: 437
Reads: 9998
Writes: 0
Duration: 440
BinaryData: (empty)
(Immediately prior to this there is a corresponding SQL:BatchStarting
trace,
with empty CPU, Reads, Writes, and Duration columns.)
What could explain the orders of magnitude difference in reads and
duration?
Is the problem due to RPC? What about the binary data? I have tried
using
the overload of ExecuteReader(CommandBehavior.SingleResult) with no
improvement. What can I try to improve it?
Thanks,
Dustin- Hide quoted text -
- Show quoted text -
I had an similar issue. I think it's due to the fragmentation of the
tables. Look at the indexes on the tables.
.
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