Emails are sent duplicated if sending emails takes more time than the check interval

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.X, 7.1.X, Master
• Fix Version/s: 7.0.0 DXP FP63, 7.0.X, 7.1.10 DXP FP3, 7.1.1 CE GA2, 7.1.10.1 SP1, 7.1.X, Master
• Component/s: Portal Services > Scheduler
• Labels:
  • ee-ts
  • liferay-dxp-70-sp10
  • liferay-dxp-71-sp1
  • liferay-fixpack-de-63-7010
  • liferay-fixpack-dxp-3-7110
• Branch Version/s:
  7.1.x, 7.0.x
• Backported to Branch:
  Committed
• Fix Priority: 3
• Git Pull Request: https://github.com/hhuijser/liferay-portal/pull/3380

Background
Announcements email notification was designed to avoid sending duplicate emails. However, to avoid a case where some announcements might get missed due to the slight delay in when scheduled jobs are really executed, a fix was introduced in LPS-31451.
This fix has side effects that can be considered as a regression bug.

Issue
Same email notification is sent multiple times if the time it takes to send the emails is higher that the scheduler check interval.

Conditions

• "announcements.entry.check.interval" is set to 1 minute
• large ammount of email recipients → sending all those emails takes more that 1 minute

Actual results
Same notification email is sent duplicated.
By the time it checks for the second time (minute 2), old process is still sending emails and new process starts to send the same emails again.

Expected results
Scheduler detects that there is already a job running and does not send the same notification email.

Note
Have not tried to reproduce it as SME already provided all the details