Bulk file upload - Stuck terribly

The problem is not in the database. The database can handle millions of records.

Are you continuing to send files when there is no connection?

I have ensured to limit the number of upload (threads?) not to exceed 20 as I read in some post. I reduce the thread counter when there is a successful upload or a failure in upload.

An important issue (or some mistake I have made ) I have noticed is that the function which inserts the new file names with the status as "WAITING" does not get listed when another function (upload function) does a.. I have a doubt if the inserts are getting committed or not to the DB. I tried the begin transaction and end transaction method also to no luck. Sometimes the inserts shows up in in the query of upload function after 5 or 6 minutes.One feature of the app is to upload a old file and the latest captured image file alternatively..



Erel, I am posting the project here.. I request you to kindly go through it and guide me please..

View attachment CamService.zip

The 20 threads limit is not relevant anymore. It is handled internally.

You should not initialize the timer in Service_Start. It will be initialized many times and this will cause problems.

About your program logic. I'm sorry but this project is too large for me to go into...

SQL Inserts are committed immediately.

Tried sending one file then the next one? Another way I could think of is zipping and sending the zip file.
Just general thoughts, haven't checked your code.