Alpha server consuming large amounts of memory

[Julian Baker]

I have recently updated a clients Alpha server to build 6012-5338 (non IIS version) and the server is continually increasing the amount of memory its using during the day to the extent that the service has to be stopped and re-started several times during the day.

Nothing has changed in terms of the applications being run or the number of users and prior to the server upgrade we did not have this issue.

Just wondered if anyone else has come across the same problem or has any advice as to how to track down the problem?

Many thanks
Julian

[Selwyn Rabins]

Julian
It sounds like their is a memory leak in one of your component. If would be very helpful if you could identify which component or .a5w page is leaking and then send us the test case.

[ssmoore1]

Hi Julian/Selwyn,

I ran into the exact same problem with the current release. I ended up having to roll back to a previous version. The memory kept increasing to the point that the application crashed (PetSitClick).

A few years back this issue used to happen to me all the time, but the releases since about 2014 have been rock solid from this perspective, I was very surprised to see it was back. But much worse because the memory creep would occur over about 4-5 hours vs. 24 hours in 2013/2014.

My plan was to wait for the next release and try using that new batch feature to recalculate all of UX components. Selwyn, any chance that could solve the problem?

When I next try to upgrade what log would be the best to capture the issue?

Cheers,

Scott

[Davidk]

Julian
It sounds like their is a memory leak in one of your component. If would be very helpful if you could identify which component or .a5w page is leaking and then send us the test case.

How would someone identify which component or .a5w page was leaking? What is the process for doing this?

[iRadiate]

Maybe this helps, seems pretty complex to me to actually determine what is causing a memory leak .. https://docs.microsoft.com/en-us/win...-a-memory-leak

I too would like Alpha's recommendation on how to go about this.

[mikeallenbrown]

Me three! I'm wondering if there is some sort of unpublished tool Alpha has to detect such an instance. Or does one have to monitor the task manager and open pages one by one and take an educated guess?

[peteconway]

Well there is a tool, I used it some years ago, (jerry brighthill from alpa gave it to me) can’t remember the details but it found whenever there was a data refresh using the timer in the UX, the memory would leak, so it does exist, there was also a toll the made the server logs actually useful. Screwed without it really.

[Davidk]

From what I understand there isn't any tool. You need to turn on all logs and run each component, one at a time, until you see the leak. It's a bit of a slog, but there's no other way to do it.

[peteconway]

Sorry David, I didn’t imagine this, it was some years ago in Nevada When the tool was made available, I no longer have access and simply don’t Remember the name of the application back in 2015, I still recommend contacting Jerry.

[Davidk]

It doesn't make sense that there is a tool and Selwyn doesn't know about it. Why would he post "identify which component or .a5w page is leaking and then send us the test case" without offering some kind of hint of how to actually identify where the leak is coming from?

[peteconway]

Well, I know I had to fight hard to get the utilities back then, so who knows.

[Davidk]

Not sure I understand. The tool was made available... and you got it from Jerry... but you had to "fight hard" for it... and you no longer have it... and there is no name for it.

[JerryBrightbill]

At one time, Alpha had a internal use only tool that could analyze the data in the Raw HTTP Logs to find the time between a request and a response, and the memory used after a response for the standard server. The format of the logs changes slightly over time, and the tool was never updated.

However, the data still exists in the Raw HTTP Log.

To find the time for a request to response, find the request in the log by looking for the header record such as

08/Aug/2018:09:32:45 -0400
Thread Name: AppServerWorker5
Thread ID: f248d9a99efa4b6ba8866703ec544570
Request Sequence: 22
Socket Handle: 4444
KeepAlive Sequence: 1
**HEADERS**

POST /myapp/aComp.a5wcmp?__virtualPage=__a5RunDialog.a5w&__dialogFilename=AComp&__alias=DLG1&__unsaved=no HTTP/1.1

The POST or GET will show the page and / or component requested, such as the component "AComp" above. To find the response, look for a match using the data in Thread ID, Request Sequence, and Socket Handle

Thread ID: f248d9a99efa4b6ba8866703ec544570
Request Sequence: 22
Socket Handle: 4444

Such as:

08/Aug/2018:09:32:45 -0400
Thread Name: AppServerWorker5
Thread ID: f248d9a99efa4b6ba8866703ec544570
Request Sequence: 22
Socket Handle: 4444
KeepAlive Sequence: 1
Sessions/Tables/Variables/Exceptions|Memory/Peak/PageFaults: 11/2/4033/0|142848000/180813824/187133
**RESPONSE**

If you compare the times in the header and response, you will see it took effectively 0 seconds. You can also find the time to build the body by looking for the **BODY** record. The Response record also has other useful information such as

Sessions/Tables/Variables/Exceptions|Memory/Peak/PageFaults: 11/2/4033/0|142848000/180813824/187133

By tracking the Memory, and the Peak memory, you can often find what requests caused memory to go up

[peteconway]

Thanks Jerry. David you really can go to far.. - could be the reason contributors to the Message Board no longer bother.

[Davidk]

Still not sure I understand. Alpha had an internal use only tool... but gave it to users... but no longer have it.

So now, in order to find a leak, you must search through hours of a log for every .a5w page and component used in an application, then find and compare the request and response each time that UX was accessed. Needle in a haystack time. This just doesn't sound right.

[asap rich]

David is literally one of the ONLY people that contribute to threads asking for help Pete. Pretty sure the forum has been this slow for years, and not because of him.

[peteconway]

Well you can see my count is 2,600 odd, no slouch myself, David is very talented and very generous, no denying it, and its appreciated by me as well, there were many talented people as generous in the year past, all I'm saying if something becomes unpleasant to do in a community, people walk or just don't bother... I say that because sometimes that's how I feel, that's all.

[kkfin]

Thanks Jerry for the great info.

Somehow I have not used this resource for a long time.

Simple hello world xbasic a5w-page seems to consume memory about 138 mb.

Checking this log has to become a routine...

Kenneth

[mikeallenbrown]

Check out today's prerelease under bug fixes.

[ssmoore1]

Thanks for the update, the fact that there is a fix to this issue is a big relief!

[peteconway]

Well it's a fix in the pre-release (good) but not the 6012-5338 official release (bad) which is displaying the issue. Be careful going live with a pre-release just to get a fix, caveat emptor.

[Davidk]

There is no difference between an "official" release and a pre-release. It's just a timing mechanism. One is no better, or worse, than the other.

An "official" release is simply a release with untested code containing bugs that developers have not yet found.

A pre-release is a release with untested code and bug fixes developers have found.

[peteconway]

Oh dear.. have you ever seen the txt files generated by debugging code in the pre-release. why would they tell you not to use in production, in my view anyone using a pre-release in a live environment is taking full responsibility for the consequences of client liability as by doing so Alpha have no obligation at all. - anyhow choose you own path based on what you now know.

[draz9]

I wish you could know when the next official release is coming out. I'd hate to do a rollback to the previous release (a big to-do at my place) only to have a new official release come out the next day.

Performance with the current release is very, very poor compared to the previous release we were running.

[lgrupido]

Alpha does not speculate on when the next official release will come out, but maybe we could hope that this particular bug warrants a hotfix?

[WebDesignShop]

Just a comment on version and the Alpha Cloud...

If you are running a system for production use, simply follow the advice of Alpha and do not use the pre-release version....EVER. If you have a dev/test setup then you can use the pre-release version no problem. The Alpha Cloud is great for testing out various versions and you can have a dev/test/prod website setup. We have started to publish with the version in the website name until it's ready to go live to it's own url. Example: https://mycoompany-mysitename-dev.cl...ware.com/6012/