PxPlus User Forum

Main Board => Discussions => Thin Client/WindX => Topic started by: Cedric on November 30, 2020, 02:42:25 PM

Title: Windx Memory access violation?
Post by: Cedric on November 30, 2020, 02:42:25 PM
Am I the only one having problems with "memory access violation" randomly on the client side (windx) while loading a screen since updated to V16.  It's not necessarily the same screen loading... could be any screen.  Some day, users don't experience the issues at all,  but other days it could happen 5-6 times a day.  Not all client has the issues, but I'd say probably 50 out of 90 clients has reported the problem.

Somebody understands the log attached? (from windx)
Title: Re: Windx Memory access violation?
Post by: Mike King on November 30, 2020, 03:50:27 PM
There was an issue on early versions of v16 caused by using ESC as a field separator in a list box.  With the ability to add pictures, bar graphs colors and other mnemonics  in the List box a ESCAPE character (the first character of any mnemonic) was incorrectly handled in some releases of V16.

To the best of our knowledge this was addressed and fixed in 16.20 however long term as a general principal you should avoid using ESC as a column/row separator character in a list box.
Title: Re: Windx Memory access violation?
Post by: Cedric on November 30, 2020, 05:07:04 PM
I'm using V16.20 on server side... The error is random... Normally, users call me just after the fact, so I rarely see it from my eyes!  I've experienced it once last week and it was while loading the main page. That screen is basically just buttons, menus, text and frames.  The buttons all have an icon (some are pvx native icons, but some are images (ICO, GIF, BMP, PNG or JPG) stored on the client PC).

Title: Re: Windx Memory access violation?
Post by: Cedric on March 06, 2021, 10:30:00 AM
Hey guys,

just a quick note that we still struggle with this problem.  I'm pretty sure something is wrong in PVX17...  I had another customer which was using V11 for a cupple of years without any issues.  Now, I have updated their server and Windx to the latest V17.10 and suddenly some users are facing that error (freezes and process stops responding on Client's PC).  It's not all users though....  I've noticed that users that had older computers with less RAM and are using Ms Teams has the issue.(it crashes 7-8 times a day)  I have disabled MsTeams and rebooted the PC and the problem seemed to have disapeared.   Now, not sure if the problem is with MsTeams or just the fact the MsTeams uses lots of Ram ( on a 4Gb Win7 64bits PC ) and causing the issue with PVX.  But, the problem wasn't present with V11 though...  Anyway, if someone reads this and knows about this, your help would be appreciated!

Title: Re: Windx Memory access violation?
Post by: Mike King on March 08, 2021, 11:56:46 AM

Its possible that there is a conflict with MS Teams although no one else has reported this. 

Its also possible that due to the fact that PxPlus V17 itself uses more memory that V11 could be compounding the issue.  Over the past eight years a lot has been added to PxPlus and some of these will increase the amount of memory being used.  The EXE itself has grown by almost 25% and the install is almost 3 times the size due to the fact we now provide an integrated Chromium browser, newer TLS1.2 support, ZIP file access, UTF8 support, improved graphic engines and many other product enhancements.

Also MS Teams has a MINIMUM requirement of 4GB -- so if that is what your systems are it leaves very little (if any) for PxPlus.
Title: Re: Windx Memory access violation?
Post by: Cedric on March 08, 2021, 01:19:56 PM
Hey Mike,

thanks for the response.  I've had this issue with another customer that was on V16... I didn't notice at that time if the users were using MsTeams.  Not all of them had only 4Gb. Some were brand new computers... The only thing I remember is that I've noticed that the users had the tendancies to open up a lot of tabs (around 20 tabs ) in their Chrome browser and it was obviously using lots or ressources.  Support said something about memory management in Windows that could've changed, but had the issue with Win7 and Win10.   That being said, it ain't normal and wish to find a fix!  If it was in my code, I could at least work on a workaround, but in this case, it's happening pretty much anywhere in the system and randomly.  There's no pattern so far which makes it really difficult to understand!

Anyway, will continue to post if I notice any relevant information that could help narrowing the cause and find a fix!

Title: Re: Windx Memory access violation?
Post by: Mike King on March 08, 2021, 01:48:46 PM

Unfortunately with Windows its pretty hard to handle out of resource issues.  There is no easy way to get a message to the end user about what is happening since to send the user a message itself requires system resources -- kind of a catch 22.

Linux generally is better as there is generally a console which you can output simple text messages to.

For Windows what you might consider is creating log files that can be checked.  PxPlus will log what it can to a logfile if present.

What we have suggested to clients in the past is to set up a directory for log files.  In your system start up, define/create a unique log file per process using something like SETDEV (0) SET "LogFile" to "..directory../"+STR(TCB(89))+".log" and in your application when you go through 'NORMAL' termination remove the file.  At the end of the day any files left are from crashed applications and their contents may assist in determining if the system reported out of memory or other problems.
Title: Re: Windx Memory access violation?
Post by: jh on May 12, 2021, 04:04:53 PM
I'm not sure if this warrants a separate thread-our customers have also started randomly experiencing "memory access violation" since upgrading from v15 but we are not running WindX and we don't use ESC as a separator.
We've implemented the logfile to collect more data and would be interested to learn more about your progress on resolving the issue.

Best regards!