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Intraweb instantly 'crashes' when above 340 users
(12-01-2021, 10:26 AM)AtozedJunky Wrote: Thank you for your replies!
For development I used Intraweb 14.2.9 with Delphi 10 Seattle (use also TMS and CGDevtools components).
The webapp is SA running as windows service.

Is the ISAPI a better approach than SA (in general for IW)?

Besides, I’m aware of newer versions, but is it possible for you to elaborate if there is any known problems regarding the sessions in older versions ?

In other words, will it help me to update or do I need to go deeper into my code? Currently I am already migrating to newer versions (Intraweb 15 and Delphi 11). I keep the older installations for backup and for small necessary adjustments in production.

What is strange for me, though, is that the issues occur after 340 sessions and 4 hours of working. If it’s indeed a thread safe error, wouldn't it be more logical for this issue to occur earlier?
Users do execute a lot of actions and retrieve a lot of data (which is handled instantly as long as we stay under 340 sessions).

-      I am using IWsession to make as much actions as possible, communicate with backed server, maintain cache datasets, load and get controls data.
-      I am not using global variables.
-      Access to server controller directly, is limited and accessed thru Critical section.
-      Communication with backed is done thru idHTTP, synchronously, inside the user session.

I pay attention to thread aware  and I do not using global variable, or if some parameters is accessed, they are treated in critical section.

No such problems are known in older versions. On the contrary, I know customers running IW 14 with up to 1000 concurrent sessions with no issues (as SA-Indy/x64).

I believe that migrating it to IW 15 would definitely help you because of a couple of factors: IW 15 performs better than 14 in several areas (render engine, lock-free session handling, even our IW 15 zLib is faster). Also you have a completely new deployment option which is Http.sys (it has the benefits of IIS - i.e. backed up by Windows http stack - and the benefits of SA Indy - because it can also be deployed as a stand alone service just like you today with very little changes).
Also, a huge list of bugs - new and old - have been continually fixed. All in all, I'd say that IW 15 scales better than 14, so even if it doesn't fix the underlying problem - whatever it is - it will definitely help in several areas.

Regarding ISAPI x SA: I personally don't like ISAPI because of the way the URL works, unless (a) you have a reverse proxy on top of it, or (b) you use URLRewrite module. Any of these can solve the url ending with "YourApp.dll", which I personally don't like.
But anyway, ISAPI is a full size truck and SA-Indy is a cargo van. They both can carry a lot of stuff, but it really depends on your cargo. We have introduced the Http.sys application in IW 15 which, in theory, is an easier to drive truck which could carry the same as the ISAPI app.

I'm curious about the issue though... you say that "issues occur after 340 sessions and 4 hours of working". Does it mean that, if you create 350 sessions in 2 hours the problem does not happen? On the other hand, if you keep it below 340 sessions what happens after 4 hours of working?

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RE: Intraweb instantly 'crashes' when above 340 users - by Alexandre Machado - 12-01-2021, 10:44 PM

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