executor: cleanup entries from mysql.db on revoke (#38370)

[ti-chi-bot]

This is an automated cherry-pick of #38370

What problem does this PR solve?

Issue Number: close #38363

Problem Summary:

Cleanup records in mysql.db where all fields are set to N.

sql> select * from mysql.db where user='u1' and host='%'\G
*************************** 1. row ***************************
                 Host: %
                   DB: te%
                 User: u1
          Select_priv: Y
          Insert_priv: Y
          Update_priv: N
          Delete_priv: N
          Create_priv: N
            Drop_priv: N
           Grant_priv: N
      References_priv: N
           Index_priv: N
           Alter_priv: N
Create_tmp_table_priv: N
     Lock_tables_priv: N
     Create_view_priv: N
       Show_view_priv: N
  Create_routine_priv: N
   Alter_routine_priv: N
         Execute_priv: N
           Event_priv: N
         Trigger_priv: N
1 row in set (0.0042 sec)

sql> REVOKE SELECT ON `te%`.* FROM 'u1'@'%';
Query OK, 0 rows affected (0.0133 sec)

sql> select * from mysql.db where user='u1' and host='%'\G
*************************** 1. row ***************************
                 Host: %
                   DB: te%
                 User: u1
          Select_priv: N
          Insert_priv: Y
          Update_priv: N
          Delete_priv: N
          Create_priv: N
            Drop_priv: N
           Grant_priv: N
      References_priv: N
           Index_priv: N
           Alter_priv: N
Create_tmp_table_priv: N
     Lock_tables_priv: N
     Create_view_priv: N
       Show_view_priv: N
  Create_routine_priv: N
   Alter_routine_priv: N
         Execute_priv: N
           Event_priv: N
         Trigger_priv: N
1 row in set (0.0043 sec)

sql> REVOKE INSERT ON `te%`.* FROM 'u1'@'%';
Query OK, 0 rows affected (0.0216 sec)

sql> select * from mysql.db where user='u1' and host='%'\G
Empty set (0.0034 sec)

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Database level privileges are cleaned up correctly 

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• dveeden
• xhebox

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[xhebox]

/cc @dveeden

[dveeden]

I tried to fix the conflict but looks like I wasn't allowed to push:

commit f1dba0e9b4348598f739af2c08b51d99e25aac0a (HEAD -> cherry-pick-38370-to-release-6.1)
Author: Daniël van Eeden <git@myname.nl>
Date:   Wed Oct 12 07:40:30 2022 +0200

    Fix merge conflict

diff --git a/executor/revoke.go b/executor/revoke.go
index ba666b175..bfa17011d 100644
--- a/executor/revoke.go
+++ b/executor/revoke.go
@@ -224,6 +224,7 @@ func (e *RevokeExec) revokeGlobalPriv(internalSession sessionctx.Context, priv *
 }
 
 func (e *RevokeExec) revokeDBPriv(internalSession sessionctx.Context, priv *ast.PrivElem, userName, host string) error {
+       ctx := context.Background()
        dbName := e.Level.DBName
        if len(dbName) == 0 {
                dbName = e.ctx.GetSessionVars().CurrentDB
@@ -237,9 +238,6 @@ func (e *RevokeExec) revokeDBPriv(internalSession sessionctx.Context, priv *ast.
        }
        sqlexec.MustFormatSQL(sql, " WHERE User=%? AND Host=%? AND DB=%?", userName, host, dbName)
 
-<<<<<<< HEAD
-       _, err = internalSession.(sqlexec.SQLExecutor).ExecuteInternal(context.Background(), sql.String())
-=======
        _, err = internalSession.(sqlexec.SQLExecutor).ExecuteInternal(ctx, sql.String())
        if err != nil {
                return err
@@ -252,7 +250,6 @@ func (e *RevokeExec) revokeDBPriv(internalSession sessionctx.Context, priv *ast.
                sqlexec.MustFormatSQL(sql, " AND %n='N'", v.ColumnString())
        }
        _, err = internalSession.(sqlexec.SQLExecutor).ExecuteInternal(ctx, sql.String())
->>>>>>> 8c9f5cfb0c (executor: cleanup entries from mysql.db on revoke (#38370))
        return err
 }
 

[xhebox]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 8892bd4

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