'show stats_meta' requires the whole mysql db privilege

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

create a user with mysql.stats_meta table select privilege granted

show stats_meta

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

I think the user should be able to execute show stats_meta

3. What did you see instead (Required)

privilege check failed, it requires the whole mysql db privilege.

The bug is in planner/core/planbuilder.go, see:

case ast.ShowStatsBuckets, ast.ShowStatsHistograms, ast.ShowStatsMeta, ast.ShowStatsExtended, ast.ShowStatsHealthy, ast.ShowStatsTopN:
		user := b.ctx.GetSessionVars().User
		var err error
		if user != nil {
			err = ErrDBaccessDenied.GenWithStackByArgs(user.AuthUsername, user.AuthHostname, mysql.SystemDB)
		}
		b.visitInfo = appendVisitInfo(b.visitInfo, mysql.SelectPriv, mysql.SystemDB, "", "", err)

4. What is your TiDB version? (Required)

mysql> select tidb_version();
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                                                                                                                                                                                                                                                           |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v5.3.0-alpha-58-g8f642929e
Edition: Community
Git Commit Hash: 8f642929e04cf35c982314c576b71bedf57d9f22
Git Branch: master
UTC Build Time: 2021-09-10 01:17:12
GoVersion: go1.16.7
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)