JobExecutor does not execute jobs with negative priorities

[mboskamp]

Environment (Required on creation)

• 7.18.2

Description (Required on creation; please attach any relevant screenshots, stacktraces, log files, etc. to the ticket)

When I use negative values for job priorities, the jobs would be executed by the job executor before 7.18.2. On 7.18.2 those jobs are never picked up for execution.

Steps to reproduce (Required on creation)

1. Create a process with a negative job priority (camunda:jobPriority="-20" on process level will configure it globally).
2. Start an instance of that process with 7.18.2.
3. Observe that no jobs are executed

Observed Behavior (Required on creation)

Jobs with negative priority are not executed on 7.18.2

Expected behavior (Required on creation)

Jobs with negative priority are executed on 7.18.2

Root Cause (Required on prioritization)

When the initial feature "I can assign the job executor to a job priority range" (CAM-13486) was developed, negative job priorities were not considered. When we changed the data type of the min and max properties from Long to long with #2826, the priority ranges were activated by default. This which would be not a problem if they would reflect the whole range of possible values. Since only values between 0 (including) and MAX_VALUE (including) are allowed this leads to the situation where jobs with negative values are not picked up.

Solution Ideas

• Make Long.MIN_VALUE the default value of jobExecutorPriorityRangeMin.
• If the user does not use the priority range feature, then the acquisition query should not contain conditions for it. This avoids unnecessary query complexity. This was changed with https://github.com/camunda/camunda-bpm-platform/issues/2826, after which the null check in the mybatis mapping doesn't work anymore

Hints

This should be added to the migration guide.

Links

https://jira.camunda.com/browse/SUPPORT-15558

Breakdown

• [x] fix on master #3078
• [x] fix on 7.18 camunda/camunda-bpm-platform-maintenance/pull/920
• [x] fix on 7.17 camunda/camunda-bpm-platform-maintenance/pull/921
• [x] document in migration guide
  • master https://github.com/camunda/camunda-docs-manual/pull/1387
  • 7.18 https://github.com/camunda/camunda-docs-manual/pull/1386
  • 7.17 https://github.com/camunda/camunda-docs-manual/pull/1385

Fixes after merge

• [x] #3081
• [x] camunda/camunda-bpm-platform-maintenance/pull/925
• [x] camunda/camunda-bpm-platform-maintenance/pull/926

Dev2QA handover

• [ ] Does this ticket need a QA test and the testing goals are not clear from the description? Add a Dev2QA handover comment

[mboskamp]

I will do the backporting once #3078 has been reviewed.

[mboskamp]

@danielkelemen, all remaining PRs are ready for review

[tasso94]

@mboskamp, heads-up to add version: labels.