[KUDU-3180] kudu don't always prefer to flush MRS/DMS that anchor more memory

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.13.0
• Assignee: YifanZhang
• Reporter: YifanZhang
• Created: 04/Aug/20 12:30
• Updated: 14/Aug/20 08:25
• Resolved: 14/Aug/20 08:25

Description

Current time-based flush policy always give a flush op a high score if we haven't flushed for the tablet in a long time, that may lead to starvation of ops that could free more memory.

We set  -flush_threshold_mb=32,  -flush_threshold_secs=1800 in a cluster, and find that some small MRS/DMS flushes has a higher perf score than big MRS/DMS flushes and compactions, which seems not so reasonable.