[LENS-1444] Optimize the algorithm of finding all eligible union candidates

• Type: Task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: cube
• Assignee: Rajat Khandelwal
• Reporter: Rajat Khandelwal
• Created: 22/Jun/17 11:07
• Updated: 06/Feb/18 05:53
• Resolved: 23/Jun/17 11:10

Description

Current algorithm is given n candidates, first find 2 ⁿ -1 union candidates using power set and then among them, remove the ones which don't cover the queried time range(s).

Proposed optimization: Pushdown of the prune logic. We'll not create a list of 2 ⁿ -1 candidates, we'll check for coverability before adding it as an eligible union candidate. This will bring down the number of UnionCandidates in the memory and preventing Full-GC.