Unstable test TestMDLStealRead

[tangenta]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Run unit test.

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

No error.

3. What did you see instead (Required)

[2023/03/09 14:52:05.047 +08:00] [INFO] [ddl.go:1166] ["[ddl] DDL job is finished"] [jobID=86]
[2023/03/09 14:52:05.047 +08:00] [INFO] [callback.go:128] ["performing DDL change, must reload"]
[2023/03/09 14:52:05.048 +08:00] [WARN] [adapter.go:1574] ["# Txn_start_ts: 0\n# User@Host: root[root] @ localhost []\n# Conn_ID: 12481372231339834270\n# Query_time: 10.469240011\n# Parse_time: 0.000117562\n# Compile_time: 0.000150979\n# Rewrite_time: 0.00002958\n# Optimize_time: 0\n# Wait_TS: 0.000042389\n# Is_internal: false\n# Digest: 1aa757c4f10460a30aeba32649a0d45e1cfcd56688709b9c54443b57f51c5a88\n# Num_cop_tasks: 0\n# Prepared: false\n# Plan_from_cache: false\n# Plan_from_binding: false\n# Has_more_results: false\n# KV_total: 0\n# PD_total: 0\n# Backoff_total: 0\n# Write_sql_response_total: 0\n# Result_rows: 0\n# Succ: true\n# IsExplicitTxn: false\n# IsSyncStatsFailed: false\nalter table test.t add column b int;"]
    mdl_test.go:646: 
        	Error Trace:	ddl/metadatalocktest/mdl_test.go:646
        	Error:      	"2023-03-09 14:51:56.579344665 +0800 CST m=+7.858772134" is not greater than "2023-03-09 14:52:05.048391619 +0800 CST m=+16.327819088"
        	Test:       	TestMDLStealRead
[2023/03/09 14:52:05.048 +08:00] [INFO] [server.go:516] ["setting tidb-server to report unhealthy (shutting-down)"]
[2023/03/09 14:52:05.054 +08:00] [INFO] [ddl_workerpool.go:82] ["[ddl] closing workerPool"]

4. What is your TiDB version? (Required)

e059bbd