[web2py] Re: Understanding Rocket Threads
Thank you Anthony, I knew session.forget() but did not know it would be so helpful for performance. I'll try that in my projects from now on. Regards, Ray On Aug 26, 2:42 am, Anthony abasta...@gmail.com wrote: If you don't explicitly forget the session, the session file will lock on each request, so subsequent requests will be blocked. Maybe you could forget the session on requests that don't need it and just keep it for requests that do need it (i.e., form submissions). Note, to immediately unlock the session file, you need to do session.forget(response), not just session.forget(). Anthony On Thursday, August 25, 2011 2:14:54 PM UTC-4, G wrote: I tried session.forget() but found that forms submitted by ajax in components don't seem to work without a session, so that won't work in my case. I also tried removing the SQLite db, it may have helped some but I'm still testing. Thanks again for the suggestions On Aug 24, 4:18 pm, Michele Comitini michele@gmail.com wrote: Try session.forget() and see what happens mic 2011/8/25 G glenn@gmail.com: Thank you for the suggestion. I made a test application that used no database accesses (no auth and randomly generated data). It showed the same behavior, so I do not think it is the culprit. In addition, since the application is monitor only, the real application only reads from the database, which I hope would not impose a transaction lock. G On Aug 24, 3:20 pm, ron_m ron.m...@gmail.com wrote: You also need to consider the database type used by the application for the model. The SQLite database has a transaction lock which will cause the application to look like it is single threaded if the database is held in a transaction pending state while the background work is performed.
[web2py] Re: Understanding Rocket Threads
Hi G,
I saw similar behaviors in some of my lightweight app, which also uses
sqlite and rocket. I need not solve that problem at that time (it was
really a little app for a small group). But I can provide some
information to you this time.
When you try to isolate the sqlite, using no auth and randomly
generating data are not enough. You would better completely take out
this line:
db = DAL('sqlite://storage.sqlite')
that means completely avoid db definition and db opening. That is
because, in web2py, even a sqlite db open attempt will open the db in
exclusive mode, hence blocking other requests to the same app. (That
was true, I don't know whether that was changed since then. Massimo
can confirm that.)
Regards,
Ray
On Aug 25, 6:37 am, G glenn.calt...@gmail.com wrote:
Thank you for the suggestion. I made a test application that used no
database accesses (no auth and randomly generated data). It showed the
same behavior, so I do not think it is the culprit. In addition, since
the application is monitor only, the real application only reads from
the database, which I hope would not impose a transaction lock.
G
On Aug 24, 3:20 pm, ron_m ron.mco...@gmail.com wrote:
You also need to consider the database type used by the application for the
model. The SQLite database has a transaction lock which will cause the
application to look like it is single threaded if the database is held in a
transaction pending state while the background work is performed.
[web2py] Re: Understanding Rocket Threads
I tried session.forget() but found that forms submitted by ajax in components don't seem to work without a session, so that won't work in my case. I also tried removing the SQLite db, it may have helped some but I'm still testing. Thanks again for the suggestions On Aug 24, 4:18 pm, Michele Comitini michele.comit...@gmail.com wrote: Try session.forget() and see what happens mic 2011/8/25 G glenn.calt...@gmail.com: Thank you for the suggestion. I made a test application that used no database accesses (no auth and randomly generated data). It showed the same behavior, so I do not think it is the culprit. In addition, since the application is monitor only, the real application only reads from the database, which I hope would not impose a transaction lock. G On Aug 24, 3:20 pm, ron_m ron.mco...@gmail.com wrote: You also need to consider the database type used by the application for the model. The SQLite database has a transaction lock which will cause the application to look like it is single threaded if the database is held in a transaction pending state while the background work is performed.
[web2py] Re: Understanding Rocket Threads
If you don't explicitly forget the session, the session file will lock on each request, so subsequent requests will be blocked. Maybe you could forget the session on requests that don't need it and just keep it for requests that do need it (i.e., form submissions). Note, to immediately unlock the session file, you need to do session.forget(response), not just session.forget(). Anthony On Thursday, August 25, 2011 2:14:54 PM UTC-4, G wrote: I tried session.forget() but found that forms submitted by ajax in components don't seem to work without a session, so that won't work in my case. I also tried removing the SQLite db, it may have helped some but I'm still testing. Thanks again for the suggestions On Aug 24, 4:18 pm, Michele Comitini michele@gmail.com wrote: Try session.forget() and see what happens mic 2011/8/25 G glenn@gmail.com: Thank you for the suggestion. I made a test application that used no database accesses (no auth and randomly generated data). It showed the same behavior, so I do not think it is the culprit. In addition, since the application is monitor only, the real application only reads from the database, which I hope would not impose a transaction lock. G On Aug 24, 3:20 pm, ron_m ron.m...@gmail.com wrote: You also need to consider the database type used by the application for the model. The SQLite database has a transaction lock which will cause the application to look like it is single threaded if the database is held in a transaction pending state while the background work is performed.
[web2py] Re: Understanding Rocket Threads
Hi, Can you explain this a bit more? Is the idea to call session.forget(response) in my main controller, but not in the components that have forms in them? I had previously put the session.forget() line in the model file so it was always executed. Thanks On Aug 25, 11:42 am, Anthony abasta...@gmail.com wrote: If you don't explicitly forget the session, the session file will lock on each request, so subsequent requests will be blocked. Maybe you could forget the session on requests that don't need it and just keep it for requests that do need it (i.e., form submissions). Note, to immediately unlock the session file, you need to do session.forget(response), not just session.forget(). Anthony On Thursday, August 25, 2011 2:14:54 PM UTC-4, G wrote: I tried session.forget() but found that forms submitted by ajax in components don't seem to work without a session, so that won't work in my case. I also tried removing the SQLite db, it may have helped some but I'm still testing. Thanks again for the suggestions On Aug 24, 4:18 pm, Michele Comitini michele@gmail.com wrote: Try session.forget() and see what happens mic 2011/8/25 G glenn@gmail.com: Thank you for the suggestion. I made a test application that used no database accesses (no auth and randomly generated data). It showed the same behavior, so I do not think it is the culprit. In addition, since the application is monitor only, the real application only reads from the database, which I hope would not impose a transaction lock. G On Aug 24, 3:20 pm, ron_m ron.m...@gmail.com wrote: You also need to consider the database type used by the application for the model. The SQLite database has a transaction lock which will cause the application to look like it is single threaded if the database is held in a transaction pending state while the background work is performed.
[web2py] Re: Understanding Rocket Threads
On Thursday, August 25, 2011 3:28:38 PM UTC-4, G wrote: Hi, Can you explain this a bit more? Is the idea to call session.forget(response) in my main controller, but not in the components that have forms in them? I had previously put the session.forget() line in the model file so it was always executed. Yes, you can put session.forget(response) anywhere (model, controller outside a function, controller inside a function). If you put it in a model file, you could make it conditional: session_actions = ['component_with_form1','component_with_form2',...] if not request.function in session_actions: session.forget(response) Anthony
[web2py] Re: Understanding Rocket Threads
I should also mention I'm open to other suggestions to alleviate this
problem. The end goal is to display information (text or image) then
request an update, and when it's ready, display the new text/
information.
G
On Aug 24, 11:39 am, G glenn.calt...@gmail.com wrote:
Hi,
First a little background: My application involves displaying and auto-
refreshing data both in the form of text from .load components and
dynamically generated images. I use JavaScript setInterval calls so
that ideally the refreshes should occur some time after the last
refresh completes. As it turns out, this does not work for the images
because using jQuery to update the .attr with the new img src returns
immediately, not after the image is loaded.
Anyway, the amount of time required to generate these images and text
data can be somewhat random, so I'm finding that my site will work for
a while, but eventually the long duration requests will pile up and
the site becomes unresponsive. Interestingly, the admin interface is
still as responsive as usual. I also notice that killing web2py will
not cause a clean exit, there will still be a thread working furiously
on the queued requests.
Thus it looks like rocket is using only one thread for the requests on
the main page, while the other threads sit idle and ready to service
other pages e.g. the admin interface. I tried to look through the code
of rocket.py to decide if this is indeed the case, but I wasn't able
to conclude one way or another. Since the admin interface is still
responsive, this does not appear to be an issue of the global
interpreter lock.
I found that starting many web2py servers on different ports, and then
directing the refresh calls to use a dedicated server for each data
source alleviated the problem somewhat, further suggesting to me that
only one thread is being used per session/browser/whatever to call it.
I expect to have no more than 2 users at a time for my application, so
I was hoping Rocket would be sufficient for this application. Would I
have better luck with apache or the like? I appreciate any advice on
the matter.
The code I'm using in the view to refresh the data is listed below
Thank you for the help,
G
View: --- default/index.html
div id=test3{{=LOAD('default','calc3.load')}}/div
img id=test2 src={{=URL('default','calc2.png')}}/img
img id=test1 src={{=URL('default','calc1.png')}}/img
script
jQuery(window).load(function()
{setCalc1Timeout();setCalc2Timeout();setCalc3Timeout()});
function updateCalc3() {
jQuery('#test3').load('{{=URL(default,calc3.load)}}',setCalc3Timeout);
}
function setCalc3Timeout() {
setTimeout(updateCalc3, 2000);
}
function setCalc2Timeout() {
setTimeout(updateCalc2,5000);
}
function updateCalc2() {
d = new Date();
jQuery('#test2').attr('src',calc2.png+?+d.getTime());
setCalc2Timeout();
}
function setCalc1Timeout() {
setTimeout(updateCalc1,5000);
}
function updateCalc1() {
d = new Date();
jQuery('#test1').attr('src',calc1.png+?+d.getTime());
setCalc1Timeout();
}
/script
[web2py] Re: Understanding Rocket Threads
You also need to consider the database type used by the application for the model. The SQLite database has a transaction lock which will cause the application to look like it is single threaded if the database is held in a transaction pending state while the background work is performed.
[web2py] Re: Understanding Rocket Threads
Thank you for the suggestion. I made a test application that used no database accesses (no auth and randomly generated data). It showed the same behavior, so I do not think it is the culprit. In addition, since the application is monitor only, the real application only reads from the database, which I hope would not impose a transaction lock. G On Aug 24, 3:20 pm, ron_m ron.mco...@gmail.com wrote: You also need to consider the database type used by the application for the model. The SQLite database has a transaction lock which will cause the application to look like it is single threaded if the database is held in a transaction pending state while the background work is performed.
Re: [web2py] Re: Understanding Rocket Threads
Try session.forget() and see what happens mic 2011/8/25 G glenn.calt...@gmail.com: Thank you for the suggestion. I made a test application that used no database accesses (no auth and randomly generated data). It showed the same behavior, so I do not think it is the culprit. In addition, since the application is monitor only, the real application only reads from the database, which I hope would not impose a transaction lock. G On Aug 24, 3:20 pm, ron_m ron.mco...@gmail.com wrote: You also need to consider the database type used by the application for the model. The SQLite database has a transaction lock which will cause the application to look like it is single threaded if the database is held in a transaction pending state while the background work is performed.
