Slow query during VerifyCalendar process in 6.2

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.2.10 EE GA1, 6.2.X EE
• Fix Version/s: 6.2.X EE
• Component/s: Calendar
• Labels:
  • ee-6.2.x-only
  • ee-ts
  • liferay-fixpack-portal-168-6210
• Branch Version/s:
  6.2.x
• Backported to Branch:
  Committed
• Story Points: 1
• Fix Priority: 3
• Git Pull Request: https://github.com/liferay/liferay-portal-ee/pull/4242

Reproduction steps:
1) Have 100000 entries in CalEvent and AssetEntry tables in 6.2. (You can find a script that adds these entries and the database as well attached)
2a) Run VerifyCalendar
or
2b) Run the following query:
select * from CalEvent left join AssetEntry on (classPK=eventId) where classPK is null;
It's from "portal-impl/src/custom-sql/calendar.xml" file

Actual result: The query is so slow and the VerifyProcess takes a lot of time