executor: grant table level privilege should check table exist

[tiancaiamao]

What problem does this PR solve?

MySQL:

mysql> grant Select,Insert,Update on test.nonexist to genius;
ERROR 1146 (42S02): Table 'test.nonexist' doesn't exist

TiDB:

mysql> grant Select,Insert,Update on test.nonexist to genius;
Query OK, 0 rows affected (0.05 sec)

Allow grant on non-exist tables causes some more serious bugs than I first thought.

mysql> grant Select,Insert,Update on test.nonexist to genius;
Query OK, 0 rows affected (0.02 sec)

mysql> grant Create on test.Nonexist to genius;
Query OK, 0 rows affected (0.02 sec)

mysql> show grants for genius;
+---------------------------------------------------------------------+
| Grants for genius@%                                                 |
+---------------------------------------------------------------------+
| GRANT Select,Insert,Update ON test.nonexist TO 'genius'@'%'         |
| GRANT Create ON test.Nonexist TO 'genius'@'%'         |
+---------------------------------------------------------------------+
4 rows in set (0.00 sec)

mysql> select * from mysql.tables_priv;                                                                                                                                                               +------+------+--------+------------+----------------+---------------------+------------------------------------+----------------------+
| Host | DB   | User   | Table_name | Grantor        | Timestamp           | Table_priv                         | Column_priv          |
+------+------+--------+------------+----------------+---------------------+------------------------------------+----------------------+
| %    | test | genius | nonexist   | root@127.0.0.1 | 2020-01-19 21:28:35 | Select,Insert,Update
| %    | test | genius | Nonexist   | root@127.0.0.1 | 2020-01-19 21:30:59 | Create
+------+------+--------+------------+----------------+---------------------+------------------------------------+----------------------+
3 rows in set (0.00 sec)

There are two records in mysql.tables_priv for genius@% and those two records are loaded, they overwrite each other.

The user genius@% doesn't really have Select,Insert,Update,Create privileges.

What is changed and how it works?

Check the table exist before the grant operation.

Check List

Tests

• Unit test

Related changes

• Need to cherry-pick to the release branch

Release note

• Write release note for bug-fix or new feature.

[tiancaiamao]

/run-all-tests

[tiancaiamao]

/run-all-tests tidb-test=pr/980

[tiancaiamao]

PTAL @imtbkcat @jackysp

[imtbkcat]

this mean we will never support wildcard in table name ?

[jackysp]

LGTM

[shenli]

LGTM

[shenli]

/merge

[sre-bot]

/run-all-tests

[sre-bot]

@tiancaiamao merge failed.

[tiancaiamao]

This one should be merged together with https://github.com/pingcap/tidb-test/pull/980

[jackysp]

/merge

[sre-bot]

/run-all-tests

[sre-bot]

cherry pick to release-3.0 failed