Improve Threadpool management.

[OrionsGuardian]

Prerequisites

• [ ] Put an X between the brackets on this line if you have done all of the following:

  • Running the latest version of Constellation

  • Attached the Support Package via Help > Support Package

  • Checked the FAQs: https://github.com/constellation-app/constellation/wiki/FAQ

  • Checked that your issue isn’t already filed: https://github.com/constellation-app/constellation/issues

  • Checked that there is not already a module that provides the described functionality: https://github.com/constellation-app/constellation/wiki/Catalogue-of-Repositories

Description

Some recent changes to the Threadpool creation/usage has caused an issue when multiple graphs are being opened during a session. The global fixed Threadpool gets fully utilised and blocks any further requests for a fixed threadpool. Specifically, when opening a graph, a fixed threadpool connection is claimed for the graph. There is a threadpool limit based on the number of logical processors available on the system. When you try to open more graphs than the number of logical processors, each additional graph will be stuck waiting for a threadpool connection to be allocated, which will never happen.

We need to change the Threadpool usage for new graphs, and the general usage across the system to improve system performance.

Steps to Reproduce

Keep creating new empty graphs until you reach a number greater than the logical processors of the machine. The last graphs will be non-responsive / unusable .

Expected behaviour: Should be able to open an unrestricted number of graphs.

Actual behaviour: Limited number can be opened, and when you go over the limit, the graph is unresponsive with no indication to the user as to why.

Reproduces how often: 100%

[HolandCrick]

@OrionsGuardian - thanks for fixing Threadpool issue when multiple graphs are being opened during a session. I have opened over 20 graphs and played with it without any issue.