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Is Coldfusion REALLY multi threaded?
Author: Jochem van Dieten
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:19512#98804
Jas
> It might not Be CF thats causing the problem, its most likley the DB thats
> escalating the Lock to a full table lock and thus preventing other users
> from running the queries until the table is free.
Pretty much the only way to get a full table lock in PostgreSQL is to
use a LOCK TABLE statement for PostgreSQL uses MVCC (a.k.a. better than
row locking). Quite unlikely.
> Also try moving the DB onto another server, as we had a simular problem,
> with ingres and moving the CF app to a new server solved the problem.
I am more thinking of a unixODBC issue (admittedly, I never was a fan of
it). If you have plans to move to CF MX you might want to test if the
concurrency is better with JDBC.
Jochem
Author: Stephen Richards
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:19512#98789
Checking the Limit Simultaneous Requsts box, and setting it to 10 certainly
has no effect. One connection doing the query, everyone else just stuck.
Interestingly, they make the connection to the database (I can see them
attempting to log in, which they do as a different user), but they get no
response from the login script until the query has finished.
It's sounding more and more like an ODBC issue
-----------------------------
Stephen Richards
020 7903 3226
------------------------------
----- Excess quoted text cut - see Original Post for more -----
Author: Mike Brunt
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:19512#98787
Fully agree with you there Dave, like yourselves at Fig Leaf we are often
involved in load-testing big web apps and that setting should be nowhere
near 40 unless this is 6 processor box. You are totally right the actual
number per processor is determined by the results of controlled and
monitored load testing.
Kind Regards - Mike Brunt, CTO
Webapper
Blog http://www.webapper.net
Web site http://www.webapper.com
Downey CA Office
562.243.6255
AIM - webappermb
Web Application Specialists
> At the moment, limit simultaneous requests is not ticked -
> perhaps I should and set it to 40. I'll try it and let
> you know.
Setting it to forty would probably not be an especially good idea - that's
an extremely high value. CF is designed to take advantage of queuing
requests - some number get simultaneously processed and the rest go into a
queue, and are serviced when free threads are available for them. This is
supposed to be faster than simply processing all the requests at once (at
least in Windows) and it's been my experience that it is, in fact, faster.
As Christine Lawson noted, the recommended number is somewhere around 3-7
threads per processor. I'd add the caveat that to find the optimal number,
load testing is required, and that you can see significant performance
differences between the optimal number and the others.
Dave Watts, CTO, Fig Leaf Software
http://www.figleaf.com/
voice: (202) 797-5496
fax: (202) 797-5444
Author: Dave Watts
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:19512#98779
> At the moment, limit simultaneous requests is not ticked -
> perhaps I should and set it to 40. I'll try it and let
> you know.
Setting it to forty would probably not be an especially good idea - that's
an extremely high value. CF is designed to take advantage of queuing
requests - some number get simultaneously processed and the rest go into a
queue, and are serviced when free threads are available for them. This is
supposed to be faster than simply processing all the requests at once (at
least in Windows) and it's been my experience that it is, in fact, faster.
As Christine Lawson noted, the recommended number is somewhere around 3-7
threads per processor. I'd add the caveat that to find the optimal number,
load testing is required, and that you can see significant performance
differences between the optimal number and the others.
Dave Watts, CTO, Fig Leaf Software
http://www.figleaf.com/
voice: (202) 797-5496
fax: (202) 797-5444
Author: Christine Lawson
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:19512#98771
Hi Stephen,
40 is an awfully high setting for Limit Simultaneous Requests, we typically
recommend you set that to 3-7 * per CPU, with 7 being on the high side.
Regards,
Christine Lawson
Macromedia
How your's works is how I would have expected.
At the moment , limit simultaneous requests is not ticked - perhaps I should
and set it to 40. I'll try it and let you know.
-----------------------------
Stephen Richards
020 7903 3226
------------------------------
> ..with regards to the long query...we have an app that has several queries
that run quite long, a couple in the 3 or 4 minute range. These do not
bring my CF server to a halt at all. We average almost 200 users per hour
on busy days on this box. Have a look at all your CFAdmin settings. You
may need to raise the 'limit simultaneous requests'. We have it set to 40
for a four proc machine. I have found through research and experience that
if your app is very DB intense, raising this helps. Also look at lowering
the 'restart at x unresponsive requests' We have it set at 5. Also make
sure you have 'timeout requests after x seconds' checked and set reasonably.
>
> note that my experiences are with winblows boxen. on Linux boxen, this
may very.
----- Excess quoted text cut - see Original Post for more -----
Author: Douglas.Knudsen
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:19512#98766
...with regards to the long query...we have an app that has several queries that
run quite long, a couple in the 3 or 4 minute range. These do not bring my CF
server to a halt at all. We average almost 200 users per hour on busy days on
this box. Have a look at all your CFAdmin settings. You may need to raise the
'limit simultaneous requests'. We have it set to 40 for a four proc machine. I
have found through research and experience that if your app is very DB intense,
raising this helps. Also look at lowering the 'restart at x unresponsive
requests' We have it set at 5. Also make sure you have 'timeout requests after
x seconds' checked and set reasonably.
note that my experiences are with winblows boxen. on Linux boxen, this may very.
Doug
----- Excess quoted text cut - see Original Post for more -----
Author: Jason Lees (National Express)
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:19512#98761
It might not Be CF thats causing the problem, its most likley the DB thats
escalating the Lock to a full table lock and thus preventing other users
from running the queries until the table is free.
Also try moving the DB onto another server, as we had a simular problem,
with ingres and moving the CF app to a new server solved the problem.
Jason Lees
Systems Developer
National Express Coaches Ltd.
> Stephen Richards wrote:
> >
> > We have 24 connections at the moment, as reported by the database.
(can't
----- Excess quoted text cut - see Original Post for more -----
how do I tell which ones are active?
Yep, I agree with you about the query, and we're taking action on that, but
it still raises the point that CF is unresponsive while a query is
executing, and I am sure it is not supposed to be. And the more users log
on, the worse it is going to become.
-----------------------------
Stephen Richards
020 7903 3226
------------------------------
Author: Jochem van Dieten
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:19512#98758
Stephen Richards wrote:
>
> We have 24 connections at the moment, as reported by the database. (can't
> use netstat because the CF server is running on the same machine as the
> database, so it's a unix socket rather than port 5423.
And how many of them are idle? In the mean time you might want to get
somebody to look at that query, since 2 minutes is rather long.
Jochem
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May 24, 2012
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