DATA RACE at the StatementStatsMap

[hawkingrei]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

2. What did you expect to see? (Required)

3. What did you see instead (Required)

==================
WARNING: DATA RACE
Write at 0x00c01d78bb30 by goroutine 58814:
  runtime.mapassign()
      GOROOT/src/runtime/map.go:578 +0x0
  github.com/pingcap/tidb/util/topsql/stmtstats.StatementStatsMap.Merge()
      util/topsql/stmtstats/stmtstats.go:162 +0x3a9
  github.com/pingcap/tidb/server.setupForTestTopSQLStatementStats.func1()
      server/tidb_test.go:2033 +0xa4
  github.com/pingcap/tidb/server.(*mockCollector).CollectStmtStatsMap()
      server/tidb_test.go:1729 +0x45
  github.com/pingcap/tidb/util/topsql/stmtstats.(*aggregator).aggregate.func2()
      util/topsql/stmtstats/aggregator.go:91 +0x56
  sync.(*Map).Range()
      GOROOT/src/sync/map.go:476 +0x1db
  github.com/pingcap/tidb/util/topsql/stmtstats.(*aggregator).aggregate()
      util/topsql/stmtstats/aggregator.go:90 +0xde
  github.com/pingcap/tidb/util/topsql/stmtstats.(*aggregator).run()
      util/topsql/stmtstats/aggregator.go:71 +0xd1
  github.com/pingcap/tidb/util/topsql/stmtstats.(*aggregator).start.func1()
      util/topsql/stmtstats/aggregator.go:56 +0x39
Previous read at 0x00c01d78bb30 by goroutine 58813:
  runtime.mapiternext()
      GOROOT/src/runtime/map.go:866 +0x0
  github.com/pingcap/tidb/server.TestTopSQLStatementStats3()
      server/tidb_test.go:2261 +0x67d
  github.com/pingcap/failpoint.(*Failpoint).Enable()
      external/com_github_pingcap_failpoint/failpoint.go:54 +0x44
  github.com/pingcap/failpoint.(*Failpoints).Enable()
      external/com_github_pingcap_failpoint/failpoints.go:105 +0x276
  github.com/pingcap/failpoint.Enable()
      external/com_github_pingcap_failpoint/failpoints.go:222 +0x8f
  github.com/pingcap/tidb/server.TestTopSQLStatementStats3()
      server/tidb_test.go:2224 +0x6b
  github.com/pingcap/failpoint.parse()
      external/com_github_pingcap_failpoint/terms.go:126 +0xad
  github.com/pingcap/failpoint.newTerms()
      external/com_github_pingcap_failpoint/terms.go:98 +0x50
  github.com/pingcap/failpoint.(*Failpoint).Enable()
      external/com_github_pingcap_failpoint/failpoint.go:54 +0x44
  github.com/pingcap/failpoint.(*Failpoints).Enable()
      external/com_github_pingcap_failpoint/failpoints.go:105 +0x276
  github.com/pingcap/failpoint.Enable()
      external/com_github_pingcap_failpoint/failpoints.go:222 +0x468
  github.com/pingcap/tidb/server.setupForTestTopSQLStatementStats()
      server/tidb_test.go:2051 +0x469
  github.com/pingcap/failpoint.parseTerm()
      external/com_github_pingcap_failpoint/terms.go:149 +0x389
  github.com/pingcap/failpoint.parse()
      external/com_github_pingcap_failpoint/terms.go:126 +0xad
  github.com/pingcap/failpoint.newTerms()
      external/com_github_pingcap_failpoint/terms.go:98 +0x50
  github.com/pingcap/failpoint.(*Failpoint).Enable()
      external/com_github_pingcap_failpoint/failpoint.go:54 +0x44
  github.com/pingcap/failpoint.(*Failpoints).Enable()
      external/com_github_pingcap_failpoint/failpoints.go:105 +0x276
  github.com/pingcap/failpoint.Enable()
      external/com_github_pingcap_failpoint/failpoints.go:222 +0x41e
  github.com/pingcap/tidb/server.setupForTestTopSQLStatementStats()
      server/tidb_test.go:2050 +0x41f
  github.com/pingcap/tidb/domain.(*Domain).rebuildSysVarCache()
      domain/sysvar_cache.go:146 +0x8c4
  github.com/pingcap/tidb/domain.(*Domain).LoadSysVarCacheLoop()
      domain/domain.go:1581 +0xa8
  github.com/pingcap/tidb/session.BootstrapSession()
      session/session.go:3325 +0x6d3
  github.com/pingcap/tidb/domain.(*Domain).GetSessionCache()
      domain/sysvar_cache.go:62 +0x5c
  github.com/pingcap/tidb/session.(*session).loadCommonGlobalVariablesIfNeeded()
      session/session.go:3672 +0x104
  github.com/pingcap/tidb/session.(*session).ExecuteStmt()
      session/session.go:2103 +0x145
  github.com/pingcap/tidb/session.(*session).ExecuteInternal()
      session/session.go:1638 +0x31b
  github.com/pingcap/tidb/domain.(*Domain).LoadPrivilegeLoop()
      domain/domain.go:1525 +0x130
  github.com/pingcap/tidb/session.BootstrapSession()
      session/session.go:3318 +0x684
  github.com/pingcap/tidb/server.createTidbTestSuiteWithCfg()
      server/tidb_test.go:102 +0x1b6
  github.com/pingcap/tidb/server.createTidbTestSuite()
      server/tidb_test.go:91 +0x21a
  github.com/pingcap/tidb/server.setupForTestTopSQLStatementStats()
      server/tidb_test.go:2041 +0x2a4
  github.com/pingcap/tidb/server.TestTopSQLStatementStats3()
      server/tidb_test.go:2222 +0x4a
  testing.tRunner()
      GOROOT/src/testing/testing.go:1576 +0x216
  testing.(*T).Run.func1()
      GOROOT/src/testing/testing.go:1629 +0x47
Goroutine 58814 (running) created at:
  github.com/pingcap/tidb/util/topsql/stmtstats.(*aggregator).start()
      util/topsql/stmtstats/aggregator.go:56 +0x19a
  github.com/pingcap/tidb/util/topsql/stmtstats.SetupAggregator()
      util/topsql/stmtstats/aggregator.go:146 +0x86
  github.com/pingcap/tidb/server.setupForTestTopSQLStatementStats()
      server/tidb_test.go:2024 +0x6e
  github.com/pingcap/tidb/server.TestTopSQLStatementStats3()
      server/tidb_test.go:2222 +0x4a
  testing.tRunner()
      GOROOT/src/testing/testing.go:1576 +0x216
  testing.(*T).Run.func1()
      GOROOT/src/testing/testing.go:1629 +0x47
Goroutine 58813 (running) created at:
  testing.(*T).Run()
      GOROOT/src/testing/testing.go:1629 +0x805
  testing.runTests.func1()
      GOROOT/src/testing/testing.go:2036 +0x8d
  testing.tRunner()
      GOROOT/src/testing/testing.go:1576 +0x216
  testing.runTests()
      GOROOT/src/testing/testing.go:2034 +0x87c
  testing.(*M).Run()
      GOROOT/src/testing/testing.go:1906 +0xb44
  go.uber.org/goleak.VerifyTestMain()
      external/org_uber_go_goleak/testmain.go:53 +0x70
  github.com/pingcap/tidb/server.TestMain()
      server/main_test.go:74 +0xe76
  main.main()
      bazel-out/k8-fastbuild/bin/server/server_test_/testmain.go:410 +0x5e8
================== 

4. What is your TiDB version? (Required)

master

HEAD is now at 4878ed3 ddl: Coalesce partition (#42476)

[crazycs520]

race in test, doesn't affect correctness, change severity from major to minor.