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CCF
31-10-2013, 10:46 AM
Hi all

This question will be bit vague due to the nature of the issue, hence am seeking for suggestions of approach and new avenues that could be explored.

The problem is that we have a custom delphi app, that converts jpgs to pdfs. We have been using this app for well over a year now. And up until recent weeks, have found this app will for some un-explicit reason will produce low-quality pdfs. Below are a few facts.


Win7 Pro environment (stand-alone, no AD)
NOD32 AV
This delphi app does not connect to the internet, but does read and write its file from our local network (small lan)
Quality such as compression values are hard coded into the app, hence end-user has no way of changing it.
Restarting the app may sometimes resolve the issue.
Restarting the pc will guarantee to resolve the issue, as if the same jpg is passed through, the before and after pdf will be noticeably different.
Prior to this issue, these computer will probably be restarted one a month at the very most.
Windows updates are done on a manual basis, issue occurred during a period where no updates were done for a long time.
Our developer has changed its jpg-pdf library, but issue appears to be still present.
Issue at this stage appears to be random, as passing 10,000 test jobs into the app may not result in any issue while sometimes after 1000 live jobs the issue may occur.
We have 3 machines running this app, all identical setups, issue has occurred on all 3 machines.
Each pc have very minimal setup, basic network, av and chrome. No mgmt app, AD, GP or such has been setup.


At this stage we are suspecting the cause of this is from an external source, but unable to locate it, as memory, cpu and network usage all appears normal (very low). We are digging into Windows Performance Log facility, but at this stage unsure on the specifics that we will need to look into or log as the issue is quite out of the blue.

Thus we are some what out of ideas so open for suggestions or method of approach in identifying and isolating the cause of the issue.


Cheers

Webdevguy
31-10-2013, 11:40 AM
Have you checked a crash log from the app? The only way you are going to be able to know what happens is to check the code for errors at the time of the crash.

Try this http://www.eurekalog.com

CCF
31-10-2013, 07:15 PM
Have you checked a crash log from the app? The only way you are going to be able to know what happens is to check the code for errors at the time of the crash.

Try this http://www.eurekalog.com

Thank you for the suggestion and the app, will have a look into it, it may assist. But as for the crash log, unfortunately the program doesnt actually crash, when the issue occurs it just performs as usual, just the output quality changes. Because we have not yet found a way to replicate the issue, our developer is also struggling to identify the issue within his code.


Cheers

wainuitech
31-10-2013, 07:49 PM
We have 3 machines running this app, all identical setups, issue has occurred on all 3 machines.

Did this happen all at the exact same time, give or take a small bit in time ??

If so ( or not) think back, what was changed, added / removed, updated etc on all 3 machines ( no matter how small or insufficient the change may appear)

CCF
01-11-2013, 08:54 AM
Did this happen all at the exact same time, give or take a small bit in time ??

If so ( or not) think back, what was changed, added / removed, updated etc on all 3 machines ( no matter how small or insufficient the change may appear)

Thanks wainuitech. The issue was spotted coming from one machine, thus when investigated into, it was found all 3 machines had produced PDFs of similar low quality, whether or not they started together or one by one, we have no clue. Because of the large quantity of jpgs that goes through these machines and because the low quality is really only visible on certain colours, its been impossible to track back on when the issue first occurred.

These machines are basically automated processing servers (virtualised), thus 95% of time are un-monitored and untouched. Anti-virus would be the only item that would automatically update...

Webdevguy
01-11-2013, 09:36 AM
Have you thought about setting up a script that tests for image quality on the colours (at the time of conversion) to check if they are at a certain level and to message an alert as soon as the low quality is detected so that you can isolate the source of the issue?

Kinda like echoing out potential errors in PHP code.

CCF
01-11-2013, 09:57 AM
Have you thought about setting up a script that tests for image quality on the colours (at the time of conversion) to check if they are at a certain level and to message an alert as soon as the low quality is detected so that you can isolate the source of the issue?

Kinda like echoing out potential errors in PHP code.

For the life of me I cant believe I did not think of this earlier, this will help alot! Thank you!

Webdevguy
01-11-2013, 10:05 AM
For the life of me I cant believe I did not think of this earlier, this will help alot! Thank you!

You can thank my server side web tutor's insistence on developing my isolating, identifying and solving the problem mentality for that bit of inspiration :)