I'm monitoring one of our servers, and on the whole it is performing
well. However, I'm puzzled by the number of LockRequests/sec that
Perfmon is recording. We frequently see values exceeding 50,000 and
the current peak is 533,616 (the average, as I type this, is 35,102).
There are only 40 users on the system.
sp_lock shows nothing like this number of locks; it shows something
of the order of 30 locks maximum for each execution, which seems far
more reasonable.
SQL Profiler seems to back up the Perfmon values; it records hundreds
of "Lock Acquired" events per second during these peak periods.
For example:
NO. OF
LOCKS OBJECT STARTTIME
===== ====== ======================
678 User_T 2005-04-15 09:03:22.863
931 User_T 2005-04-15 09:03:22.877
924 User_T 2005-04-15 09:03:22.893
16 EnquiryUser_T 2005-04-15 09:03:22.893
961 User_T 2005-04-15 09:03:22.910
820 User_T 2005-04-15 09:03:22.923
4 NULL 2005-04-15 09:03:22.923
828 User_T 2005-04-15 09:03:22.940
4 NULL 2005-04-15 09:03:22.940
734 User_T 2005-04-15 09:03:22.957
Can anyone think why such a comparatively small system should generate
these numbers of locks? Why does sp_lock NOT show the same level of
locking? 4 32001
sp_lock is a point in time capture of the locks so it may not match the per
second count.
If you have a high number of lock requests, with low request rate (i.e.
small system), it usually is another indicator that SQL Server has to do
table scans when retrieving data.
Look at http://www.sql-server-performance.com on how to find the queries
that are causing it and how to remedy it.
Regards
--------------------------------
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mi**@epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"Phil" <ph*********@gmail.com> wrote in message
news:11**********************@z14g2000cwz.googlegr oups.com... I'm monitoring one of our servers, and on the whole it is performing well. However, I'm puzzled by the number of LockRequests/sec that Perfmon is recording. We frequently see values exceeding 50,000 and the current peak is 533,616 (the average, as I type this, is 35,102). There are only 40 users on the system.
sp_lock shows nothing like this number of locks; it shows something of the order of 30 locks maximum for each execution, which seems far more reasonable.
SQL Profiler seems to back up the Perfmon values; it records hundreds of "Lock Acquired" events per second during these peak periods.
For example:
NO. OF LOCKS OBJECT STARTTIME ===== ====== ====================== 678 User_T 2005-04-15 09:03:22.863 931 User_T 2005-04-15 09:03:22.877 924 User_T 2005-04-15 09:03:22.893 16 EnquiryUser_T 2005-04-15 09:03:22.893 961 User_T 2005-04-15 09:03:22.910 820 User_T 2005-04-15 09:03:22.923 4 NULL 2005-04-15 09:03:22.923 828 User_T 2005-04-15 09:03:22.940 4 NULL 2005-04-15 09:03:22.940 734 User_T 2005-04-15 09:03:22.957
Can anyone think why such a comparatively small system should generate these numbers of locks? Why does sp_lock NOT show the same level of locking?
Hi
You may want to look monitor lock escalation and deadlocks in Profiler as
well, this should indicate where they are being taken out.
John
"Phil" <ph*********@gmail.com> wrote in message
news:11**********************@z14g2000cwz.googlegr oups.com... I'm monitoring one of our servers, and on the whole it is performing well. However, I'm puzzled by the number of LockRequests/sec that Perfmon is recording. We frequently see values exceeding 50,000 and the current peak is 533,616 (the average, as I type this, is 35,102). There are only 40 users on the system.
sp_lock shows nothing like this number of locks; it shows something of the order of 30 locks maximum for each execution, which seems far more reasonable.
SQL Profiler seems to back up the Perfmon values; it records hundreds of "Lock Acquired" events per second during these peak periods.
For example:
NO. OF LOCKS OBJECT STARTTIME ===== ====== ====================== 678 User_T 2005-04-15 09:03:22.863 931 User_T 2005-04-15 09:03:22.877 924 User_T 2005-04-15 09:03:22.893 16 EnquiryUser_T 2005-04-15 09:03:22.893 961 User_T 2005-04-15 09:03:22.910 820 User_T 2005-04-15 09:03:22.923 4 NULL 2005-04-15 09:03:22.923 828 User_T 2005-04-15 09:03:22.940 4 NULL 2005-04-15 09:03:22.940 734 User_T 2005-04-15 09:03:22.957
Can anyone think why such a comparatively small system should generate these numbers of locks? Why does sp_lock NOT show the same level of locking?
As mentioned in the original post, I've already monitored this in
Profiler (this is where the figures displayed in that post came from),
and it returns the same level of locking as indicated by Perfmon.
Whilst I agree that sp_lock is 'point-in-time' rather than a whole
second, the sp_lock counts are so much lower than Perfmon that I can't
see them reaching these maximum figures if they could be accumulated
over a whole second. I just don't believe that a 4Gb database on a
system with 45 users can regularly generate >500,000 lock requests per
second, especially as the value for LockWaits/sec are very low : <
0.004 and the TableLockEscalations/Sec are virtually zero . If we
were tablescanning massively, I would expect both these measurements to
be much higher than they are.
I'm still puzzled.
Hi
If you have table cans you could see them in profiler, but I would expect
you to see Lock Escallation as well if that was happening.
What you don't say is what type of locks these are, if they are related to
user processes or system processes. If this is a user process then what is
the user doing at that time?
John
"Phil" <ph*********@gmail.com> wrote in message
news:11*********************@o13g2000cwo.googlegro ups.com... As mentioned in the original post, I've already monitored this in Profiler (this is where the figures displayed in that post came from), and it returns the same level of locking as indicated by Perfmon.
Whilst I agree that sp_lock is 'point-in-time' rather than a whole second, the sp_lock counts are so much lower than Perfmon that I can't see them reaching these maximum figures if they could be accumulated over a whole second. I just don't believe that a 4Gb database on a system with 45 users can regularly generate >500,000 lock requests per second, especially as the value for LockWaits/sec are very low : < 0.004 and the TableLockEscalations/Sec are virtually zero . If we were tablescanning massively, I would expect both these measurements to be much higher than they are.
I'm still puzzled. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: Christoph Zeltner |
last post by:
hi,
i am writing a thesis on the concurrency control in db2 udb and oracle. I
found in the documentary of db2, that
a resource holding a (U)pdate-Lock can still be requested by a read-lock...
|
by: db2group88 |
last post by:
we are using db2 udb v8.1 on windows, the configure parameter for
locks is locklist 1000, maxlocks 60, but somehow i still have the
error message
ADM5502W The escalation of "1" locks on table...
|
by: Lara |
last post by:
Hello freaks,
we have many problems with our online reorg and no idea how to resolve
it.
We had to do an online reorg beacause of 24 h online business.
We start the reorg-statements (table by...
|
by: Rick Strahl [MVP] |
last post by:
Hi all,
I have an ASP.Net application that's online that's 'locking up' from time to
time. It doesn't completely lock up but all of a sudden it appears to be
stuck for about 20-30 seconds,...
|
by: Thomas Nielsen [AM Production A/S] |
last post by:
Hi,
I have one web form (WebForm1.aspx) from which i would like to display the
output of another web form, WebForm2.aspx, in a controlled environment. I do
this by using HttpWebRequest to...
| |
by: Kevin Frey |
last post by:
Hello,
I've been reading that ASP.NET serialises (ie. processes one at a time) HTTP
requests if two simultaneous requests need to access the same session state.
It also makes note that ASP.NET...
|
by: Bob Bins |
last post by:
Is there a way to create a shared lock using the Monitor class or any other
synchronization class in .NET?
So I have one resource that may have multiple threads using it at once but a
second...
|
by: Tim_Mac |
last post by:
hi,
i'm generating PDF files from crystal reports in my .Net 1.1 web site, and
saving them to disk for the user to download in their own time.
the format i'm currently using is: ...
|
by: polastine |
last post by:
Hi Anthony --
Anthony Jones wrote:
OK, figured as much. I'm not forking any threads myself.
2.0, currently. Why? Is there a difference/advantage? I can probably go
to 3.x if there's a...
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However,...
|
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven...
| |
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing,...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
| |
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| | |