domain, statistics: periodically update stats healthy distribution (#39739) #50985
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This is an automated cherry-pick of #39739
What problem does this PR solve?
Issue Number: close #39349
Problem Summary:
What is changed and how it works?
Update stats healthy distribution metrics periodically, which is easy to implement and can avoid corner cases like #39349.
Check List
Tests
tiup playground nightly --db 2 --db.binpath /Users/xuyifan/tidb/bin/tidb-server --kv 3 --tiflash 0
PS: I found that after dropping table
t2
, stats oft2 global
are removed from cache very soon while stats ofp0
,p1
,p2
still exist in cache until GCStats is triggered. However, if we don't executealter table t2 drop partition p3
and directlydrop table t2
, partition stats are removed from cache very soon. It is a minor problem and the pr doesn't handle it.Side effects
Documentation
Release note
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