checker: avoid to merge region with high qps

[lhy1024]

Signed-off-by: lhy1024 admin@liudos.us

What problem does this PR solve?

avoid to merge region with high qps

Check List

Tests

• Unit test
• Integration test

Release note

checker: avoid to merge region with high qps

[codecov]

Codecov Report

Merging #3805 (366b90b) into master (7039dab) will increase coverage by 0.01%.
The diff coverage is 85.71%.

@@            Coverage Diff             @@
##           master    #3805      +/-   ##
==========================================
+ Coverage   75.03%   75.04%   +0.01%     
==========================================
  Files         245      245              
  Lines       24597    24604       +7     
==========================================
+ Hits        18456    18464       +8     
+ Misses       4518     4517       -1     
  Partials     1623     1623              

Flag	Coverage Δ
unittests	75.04% <85.71%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/mock/mockcluster/config.go	96.77% <0.00%> (-3.23%)	⬇️
server/config/config.go	74.94% <100.00%> (+0.10%)	⬆️
server/config/persist_options.go	92.60% <100.00%> (+1.20%)	⬆️
server/schedule/checker/merge_checker.go	76.66% <100.00%> (+0.80%)	⬆️
pkg/tempurl/tempurl.go	45.00% <0.00%> (-15.00%)	⬇️
server/statistics/hot_cache_task.go	75.00% <0.00%> (-4.17%)	⬇️
pkg/etcdutil/etcdutil.go	84.70% <0.00%> (-3.53%)	⬇️
server/tso/tso.go	70.78% <0.00%> (-2.25%)	⬇️
server/schedulers/utils.go	93.90% <0.00%> (-1.02%)	⬇️
server/core/storage.go	67.68% <0.00%> (-0.77%)	⬇️
... and 16 more

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[nolouch]

can we know this from TiKV? I think we can use ConfigManager.

[lhy1024]

How to use ConfigManager？And I think we can also get StoreHeartbeatInterval and RegionHeartbeatInterval from it.

[rleungx]

What if this threshold is not the same between PD and TiKV?

[lhy1024]

When the pd threshold is higher than the tikv threshold, some regions may not be merged as expected, and conversely, some regions that were just split by qps may be merged again, so we expect them to be the same, or not much different

[ti-chi-bot]

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• disksing

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[disksing]

I think we need some document update.

[lhy1024]

Considering that qps will be used as the dimension for reading hotspot scheduling and that the merge checker will skip regions already identified as hotspots, this pr is unnecessary and I will close it.