[ISSUE-388][ISSUE-244][Bug] Fix incorrect usage of GRPCMetrics#setGauge

[xianjingfeng]

What changes were proposed in this pull request?

Fix incorrect usage of GRPCMetrics#setGauge

Why are the changes needed?

It is a bug #244 #388

Does this PR introduce any user-facing change?

No

How was this patch tested?

No need

[xianjingfeng]

PTAL @jerqi @zuston

[jerqi]

Could you explain why it will cause these problems?

[xianjingfeng]

Could you explain why it will cause these problems?

Thread1: activeThreadSize.incrementAndGet()
Thread2: activeThreadSize.incrementAndGet()
Thread2: setGauge(2)
Thread1: setGauge(1)
final result: 1
expected result: 2

[codecov-commenter]

Codecov Report

Merging #404 (47eacdd) into master (45e600c) will decrease coverage by 0.63%.
The diff coverage is 66.66%.

@@             Coverage Diff              @@
##             master     #404      +/-   ##
============================================
- Coverage     59.20%   58.57%   -0.64%     
- Complexity     1471     1608     +137     
============================================
  Files           181      194      +13     
  Lines          9705    10996    +1291     
  Branches        839      963     +124     
============================================
+ Hits           5746     6441     +695     
- Misses         3612     4174     +562     
- Partials        347      381      +34     

Impacted Files	Coverage Δ
...le/common/rpc/MonitoringServerTransportFilter.java	0.00% <0.00%> (ø)
...org/apache/uniffle/common/metrics/GRPCMetrics.java	46.37% <71.42%> (+6.37%)	⬆️
...java/org/apache/uniffle/common/rpc/GrpcServer.java	25.45% <100.00%> (-2.62%)	⬇️
.../hadoop/mapreduce/task/reduce/RssEventFetcher.java	88.57% <0.00%> (ø)
.../hadoop/mapreduce/task/reduce/RssBypassWriter.java	61.90% <0.00%> (ø)
...n/java/org/apache/hadoop/mapreduce/MRIdHelper.java	0.00% <0.00%> (ø)
...java/org/apache/hadoop/mapred/SortWriteBuffer.java	90.90% <0.00%> (ø)
...pache/hadoop/mapreduce/task/reduce/RssFetcher.java	90.90% <0.00%> (ø)
...preduce/task/reduce/RssRemoteMergeManagerImpl.java	82.43% <0.00%> (ø)
...g/apache/hadoop/mapred/SortWriteBufferManager.java	80.10% <0.00%> (ø)
... and 6 more

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[jerqi]

Could you explain why it will cause these problems?

Thread1: activeThreadSize.incrementAndGet() Thread2: activeThreadSize.incrementAndGet() Thread2: setGauge(2) Thread1: setGauge(1) final result: 1 expected result: 2

Got it.

[jerqi]

LGTM, thanks @xianjingfeng

[zuston]

Make sense. A problem: Gauge is thread safe?

[xianjingfeng]

Make sense. A problem: Gauge is thread safe?

Yes, it use DoubleAdder which is same as java.util.concurrent.atomic.DoubleAdder

[zuston]

LGTM