Coldfusion 2016
Microsoft Server 2012
Oracle 12
ODBC connection
I turned on profiling and monitoring and now I can see that there are requests that are stuck and cannot be terminated by the CF monitor; Some are over 200k seconds.
I know I can increase the number of simultaneous requests but I want to solve the underlying problem. As I read the stack traces of these “zombie requests” they are getting stuck on and some are in but some are not. I ran the query in my oracle client and they resolve instantly.
Is there a way to terminate these requests or prevent this from happening at all?
EDIT: The server monitor does not treat these requests as slow or hung, the alerts are not triggering for any of these. Honestly, they should have be going off constantly considering how many of these there are.
Also, the execution time is a mere .003 seconds so what happened? Why doesn't ColdFusion know this?
An example of a "zombie"
The active query that is stuck
We have a similar situation with a different database engine - redbrick, which runs on a unix server. We solved it as follows.
We set up a cron job on the database server to run every 5 minutes. This job uses a combination of unix and awk commands.
This job runs a query against the system table that looks for queries that have been running for more than 120 seconds, where the database account is the one used by ColdFusion. Records are outputted to a file. Something like this:
print "alter system cancel user command userName process " $1 ";"
$1 comes from the query and is the process Id we want to stop.
Then we run the file, which executes all those alter system commands.
With a different database engine, and possible different OS for the database server, the details would be different, but the approach should work.
Edit Starts Here
To prevent recurrence, look at the pages that call the ones with the long running queries. If impatient users are able to repeatedly click something because nothing is happening, do something about that. You can use javascript to make the link/button go away. Alternatively, you can go to an intermediate page with a display for the user and something that carries them through to the real page.
Related
I have a particular scheduled task that CF claims runs every 2 minutes. However, it either doesn't run or complete since the database changes the task is supposed to perform do not occur after each run. However if I copy the exact same URL into a browser and run the script, it works 100% of the time.
I have no clue where to start debugging. There is no IP restriction on the page.
I can see in the CF Admin that it was last run at 2:06 for example and the next run will be at 2:08. I can also see it in the scheduler.log file.
We had updated our certs in IIS but didn't update our cacerts file. Once we did everything was great.
It was clear the process wasn't running when I added a line or two to email myself at the start of the task. The emails never came when the server ran the task but they did when I pinged the page. I changed the task to save the output to a log file and when I opened that up it just said "Connection Failure". This led me to some googling and some talk about certificates which made me remember that we just updated ours recently. Looking back at my emails with IT it did indeed happen on the same day that the last emails in the mailsent.log were sent from these scheduled tasks.
I have a series of scheduled tasks that all run at various times of the day. Since the migration from Coldfusion version 7 to 10, these tasks have stopped running.
When I check the box, that outputs the results to a file, I get a text file that says nothing more than "Connection Failure". I have tried everything imaginable regarding the username and password for the task. It makes no difference. When I run the CFM page in my browser, the
page works correctly and generates an email just like it should. I just
can't make it run as a scheduled event.
Is the scheduled task folder has any check for the session or anything? I mean is the scheduled task folder is accessible without login? Please try with removing all the redirect rules for the application. That might work.
For me the requests were timing out. I increased the timeout in the administrator and that solved it. Doing a cfhttp in a test file and dumping the results helped me troubleshoot it.
I have a series of scheduled tasks that all run at various times of the day. Since the migration from Coldfusion version 7 to 10, these tasks have stopped running.
When I check the box, that outputs the results to a file, I get a text file that says nothing more than "Connection Failure". I have tried everything imaginable regarding the username and password for the task. It makes no difference. When I run the CFM page in my browser, the
page works correctly and generates an email just like it should. I just
can't make it run as a scheduled event.
Is the scheduled task folder has any check for the session or anything? I mean is the scheduled task folder is accessible without login? Please try with removing all the redirect rules for the application. That might work.
For me the requests were timing out. I increased the timeout in the administrator and that solved it. Doing a cfhttp in a test file and dumping the results helped me troubleshoot it.
I'm working on a script that creates a MySQL dump via <cfexecute> and then FTPs the SQL script to another server. I've resorted to checking once per second to see if the filesize has changed, and if it has not changed within the past five seconds I assume it has completed.
This is fine for the current application, but eventually I would like to be able to import the SQL script on the second server and provide some sort of notification that it has completed.
Is there some way to track the status of a running process?
If not, is there a way to accomplish a full DB export and import via ColdFusion alone?
Actually you may not realize it, but when you call <cfexecute> without passing a timeout attribute it defaults to '0' timeout. And if you read the docs on <cfexecute> you'd see:
If the value is 0:
ColdFusion starts a process and returns immediately. ColdFusion may
return control to the calling page
before any program output displays. To
ensure that program output displays,
set the value to 2 or higher.
So I would suggest passing a higher value for timeout which will cause ColdFusion to wait for mysqldump to complete before moving on.
Reference
Check out Event Gateways[1] for one way to deal with asynchronous operations. There's a Directory Watcher gateway that comes with CF as an example.[2]
Barring that, create some sort of batch processing facility using CF Scheduled Tasks. Add the job to a database table and have a scheduled task periodically pull jobs out of the table and execute them, reporting on the result. A second scheduled task can detect that the first completed and carry out the next step of the process.
[1] http://help.adobe.com/en_US/ColdFusion/9.0/CFMLRef/WSc3ff6d0ea77859461172e0811cbec214e3-7fa7.html
[2] http://help.adobe.com/en_US/ColdFusion/9.0/Developing/WSc3ff6d0ea77859461172e0811cbec22c24-77f7.html
I am running Django on Apache. I have several client computers which should call urllib2.urlopen() and send over some data which my server will process and immediately send back a reply. However, when I am testing this I found a very tricky issue. I have one client repeatedly send the same data to be processed. The first time, it takes around ~20 seconds, second time, it takes about 40 seconds, third time I get a 504 (gateway timeout) error. If I try to send data some more 504 errors randomly pop up. I am pretty sure this is an issue with Postgres as the function that processes the information makes many database calls, however, I do not know why the performance of Postgres would decline so much. I have tried several database optimization tricks, including this one: (http://stackoverflow.com/questions/1125504/django-persistent-database-connection), to no avail.
Thanks in advance.
Edit: The requests are not coming concurrently. They are coming in back to back and each query involves a lot of SELECTs and JOINs, and there are a few INSERTs and UPDATEs as well. The apache error logs show that it is just a simple timeout, where the function to process the client posted data takes over 90 seconds.
If it's really Postgres, then you should turn on the logging of slow statements in the Postgres configuration to find out which statement exactly is taking so much time.
This can be done by setting the configuration property log_min_duration.
Details are in the manual:
http://www.postgresql.org/docs/current/static/runtime-config-logging.html#GUC-LOG-MIN-DURATION-STATEMENT
You say the function makes "many database calls" so I'd start with a very low number, or even 0 to log the duration of all statements, then you might be able to identify the slow ones.
It could also be a locking issued. Maybe the first call does not end its transaction properly and subsequent calls run into a timeout when waiting for a resource.
You can verify this by checking the system view pg_locks after the first call.
Have you checked the Apache error_logs? Have you set django DEBUG = True or ADMINS = ('email#addr.com',) so you can get a detailed error report about what the actual cause of the issue is? If so, how about pasting some information here.
Why are you certain that it's postgres? Have you done diagnostics to come to that conclusion? If so, please let us know.
Are you running apache with mod_wsgi? How many processes and threads have you allocated to your django application?
Also, 20 seconds to process the first transaction is a huge amount of time. Perhaps you could show us the view code that is causing the time out. We may be able to help there.
I sincerely doubt that it's going to be postgres alone that is causing the issue. It probably has something to do with application code, or server configuration.