[ https://issues.apache.org/jira/browse/KUDU-3180?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17172925#comment-17172925 ]
YifanZhang commented on KUDU-3180: ---------------------------------- Thanks [~aserbin]. I agree that using {{memory_size * time_since_last_flush}} instead of just {{time_since_last_flush}} to pick which MRS should be flush is a easy way to improve current policy. Also if we prefer flush to compactions, current policy ensures that if an MRS over {{flush_threshold_mb}}, a flush will be more likely to be selected than a compaction. > kudu don't always prefer to flush MRS/DMS that anchor more memory > ----------------------------------------------------------------- > > Key: KUDU-3180 > URL: https://issues.apache.org/jira/browse/KUDU-3180 > Project: Kudu > Issue Type: Bug > Reporter: YifanZhang > Priority: Major > Attachments: image-2020-08-04-20-26-53-749.png, > image-2020-08-04-20-28-00-665.png > > > 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. > !image-2020-08-04-20-26-53-749.png|width=1424,height=317!!image-2020-08-04-20-28-00-665.png|width=1414,height=327! -- This message was sent by Atlassian Jira (v8.3.4#803005)