table: fix show index for the partitioned table

[ciscoxll]

What have you changed? (mandatory)

• fix show index for the partitioned table.
• I want to get the IndexInfo from the partition table, but getting the IndexInfo is always empty.
• Looking at the logs, it is normal for UpdateTable to update the IndexInfo.
• Finally found, table partitioning no initializes the indices of the tableCommon.
• Fix issue Can not show index for the partitioned table #7345

master branch

mysql> set @@tidb_enable_table_partition = 1;
Query OK, 0 rows affected (0.00 sec)

mysql> create table partition_drop_idx (
    ->         c1 int, c2 int, c3 int
    ->     )
    ->     partition by range( c1 ) (
    ->         partition p0 values less than (1990),
    ->         partition p1 values less than (1995),
    ->         partition p2 values less than (2000),
    ->         partition p3 values less than (2005),
    ->         partition p4 values less than (2010),
    ->         partition p5 values less than (2015)
    ->        );
Query OK, 0 rows affected (0.12 sec)

mysql> alter table partition_drop_idx add index idx1 (c1);
Query OK, 0 rows affected (0.04 sec)
mysql> show index from  partition_drop_idx;
Query OK, 0 rows affected (0.04 sec)

show-index branch

mysql> set @@tidb_enable_table_partition = 1;
Query OK, 0 rows affected (0.00 sec)

mysql> create table partition_drop_idx (
    ->         c1 int, c2 int, c3 int
    ->     )
    ->     partition by range( c1 ) (
    ->         partition p0 values less than (1990),
    ->         partition p1 values less than (1995),
    ->         partition p2 values less than (2000),
    ->         partition p3 values less than (2005),
    ->         partition p4 values less than (2010),
    ->         partition p5 values less than (2015)
    ->        );
Query OK, 0 rows affected (0.12 sec)

mysql> alter table partition_drop_idx add index idx1 (c1);
Query OK, 0 rows affected (0.04 sec)
mysql> show index from  partition_drop_idx;
+--------------------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table              | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+--------------------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| partition_drop_idx |          1 | idx1     |            1 | c1          | A         |           0 |     NULL | NULL   | YES  | BTREE      |         |               |
+--------------------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
1 row in set (0.00 sec)

What is the type of the changes? (mandatory)

Bug fix

• Bug fix (non-breaking change which fixes an issue)

How has this PR been tested? (mandatory)

Unit tests.

Does this PR affect documentation (docs/docs-cn) update? (mandatory)

No

Does this PR affect tidb-ansible update? (mandatory)

No

Does this PR need to be added to the release notes? (mandatory)

No

[zz-jason]

/run-all-tests

[winkyao]

The fix is wrong.

[ciscoxll]

@winkyao @tiancaiamao PTAL.

[zhexuany]

adding show index test case?

[tiancaiamao]

Is it the cause of this issue #7308

[ciscoxll]

@winkyao @tiancaiamao @zhexuany PTAL.

[zhexuany]

LGTM

[winkyao]

LGTM

[ciscoxll]

/run-all-tests

[ciscoxll]

/run-all-tests

[tiancaiamao]

LGTM