Unstable test explainfor_test.go: testSerialSuite.TestExplainFor

[sre-bot]

Latest build: https://internal.pingcap.net/idc-jenkins/job/tidb_ghpr_check_2/70254/display/redirect

[sre-bot]

Yet another case failure: https://internal.pingcap.net/idc-jenkins/job/tidb_ghpr_check_2/70254/display/redirect

[zhouqiang-cl]

2021-08-05T08:50:08.515Z] FAIL: explainfor_test.go:78: testSerialSuite.TestExplainFor

[2021-08-05T08:50:08.515Z] 

[2021-08-05T08:50:08.515Z] explainfor_test.go:126:

[2021-08-05T08:50:08.515Z]     check()

[2021-08-05T08:50:08.515Z] explainfor_test.go:119:

[2021-08-05T08:50:08.515Z]     c.Assert(buf.String(), Matches, ""+

[2021-08-05T08:50:08.515Z]         "TableReader_5 10000.00 0 root  time:.*, loops:1, cop_task: {num:.*, max:.*, proc_keys: 0, rpc_num: 1, rpc_time:.*} data:TableFullScan_4 N/A N/A\n"+

[2021-08-05T08:50:08.515Z]         "└─TableFullScan_4 10000.00 0 cop.* table:t1 tikv_task:{time:.*, loops:0} keep order:false, stats:pseudo N/A N/A")

[2021-08-05T08:50:08.515Z] ... value string = "" +

[2021-08-05T08:50:08.515Z] ...     "TableReader_5 10000.00 0 root  time:3.45ms, loops:1, cop_task: {num: 1, max: 2.8ms, proc_keys: 0, tot_proc: 2ms, rpc_num: 1, rpc_time: 2.57ms, copr_cache_hit_ratio: 0.00} data:TableFullScan_4 N/A N/A\n" +

[2021-08-05T08:50:08.515Z] ...     "└─TableFullScan_4 10000.00 0 cop[tikv] table:t1 tikv_task:{time:0s, loops:0} keep order:false, stats:pseudo N/A N/A"

[2021-08-05T08:50:08.515Z] ... regex string = "" +

[2021-08-05T08:50:08.515Z] ...     "TableReader_5 10000.00 0 root  time:.*, loops:1, cop_task: {num:.*, max:.*, proc_keys: 0, rpc_num: 1, rpc_time:.*} data:TableFullScan_4 N/A N/A\n" +

[2021-08-05T08:50:08.515Z] ...     "└─TableFullScan_4 10000.00 0 cop.* table:t1 tikv_task:{time:.*, loops:0} keep order:false, stats:pseudo N/A N/A"

[2021-08-05T08:50:08.515Z] 

in ci https://ci.pingcap.net/blue/organizations/jenkins/tidb-unit-test-nightly/detail/tidb-unit-test-nightly/7608/pipeline

[tiancaiamao]

Seems related to statement summary, PTAL @crazycs520

[tiancaiamao]

This issue has been there for quite a long time.
After #30822, I guess it's solved.
Close for now, if it still reproduce, feel free to reopen.