ddl: split partition region when add a new partition

[crazycs520]

Signed-off-by: crazycs520 crazycs520@gmail.com

What problem does this PR solve?

Split new region when add partitions.

before

mysql>create table t (a int, b int,index(a)) PARTITION BY RANGE (a) (
      PARTITION p0 VALUES LESS THAN (10),
      PARTITION p1 VALUES LESS THAN (20),
      PARTITION p2 VALUES LESS THAN (30));
Query OK, 0 rows affected
Time: 0.072s
mysql>show table t regions;
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
| REGION_ID | START_KEY | END_KEY | LEADER_ID | LEADER_STORE_ID | PEERS            | SCATTERING | WRITTEN_BYTES | READ_BYTES | APPROXIMATE_SIZE(MB) | APPROXIMATE_KEYS |
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
| 1748      | t_1363_   | t_1364_ | 1749      | 4               | 1749, 1750, 1751 | 0          | 0             | 0          | 1                    | 0                |
| 1752      | t_1364_   | t_1365_ | 1753      | 4               | 1753, 1754, 1755 | 0          | 0             | 0          | 1                    | 0                |
| 6         | t_1365_   |         | 17        | 4               | 17, 18, 21       | 0          | 214           | 0          | 1                    | 490620           |
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
3 rows in set
Time: 0.009s
mysql>alter table t add partition ( partition p3 values less than (40), partition p4 values less than (50) );
Query OK, 0 rows affected
Time: 0.070s
mysql>show table t regions;
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
| REGION_ID | START_KEY | END_KEY | LEADER_ID | LEADER_STORE_ID | PEERS            | SCATTERING | WRITTEN_BYTES | READ_BYTES | APPROXIMATE_SIZE(MB) | APPROXIMATE_KEYS |
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
| 1748      | t_1363_   | t_1364_ | 1749      | 4               | 1749, 1750, 1751 | 0          | 0             | 0          | 1                    | 0                |
| 1752      | t_1364_   | t_1365_ | 1753      | 4               | 1753, 1754, 1755 | 0          | 0             | 0          | 1                    | 0                |
| 6         | t_1365_   |         | 17        | 4               | 17, 18, 21       | 0          | 214           | 0          | 1                    | 490620           |
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
3 rows in set

This PR

mysql>create table t (a int, b int,index(a)) PARTITION BY RANGE (a) (
      PARTITION p0 VALUES LESS THAN (10),
      PARTITION p1 VALUES LESS THAN (20),
      PARTITION p2 VALUES LESS THAN (30));
Query OK, 0 rows affected
Time: 0.073s
mysql>show table t regions;
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
| REGION_ID | START_KEY | END_KEY | LEADER_ID | LEADER_STORE_ID | PEERS            | SCATTERING | WRITTEN_BYTES | READ_BYTES | APPROXIMATE_SIZE(MB) | APPROXIMATE_KEYS |
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
| 1760      | t_1374_   | t_1375_ | 1761      | 4               | 1761, 1762, 1763 | 0          | 0             | 0          | 1                    | 0                |
| 1764      | t_1375_   | t_1376_ | 1765      | 4               | 1765, 1766, 1767 | 0          | 0             | 0          | 1                    | 0                |
| 6         | t_1376_   |         | 17        | 4               | 17, 18, 21       | 0          | 214           | 0          | 1                    | 0                |
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
3 rows in set
Time: 0.011s
mysql>alter table t add partition ( partition p3 values less than (40), partition p4 values less than (50) )
Query OK, 0 rows affected
Time: 0.071s
mysql>show table t regions;
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
| REGION_ID | START_KEY | END_KEY | LEADER_ID | LEADER_STORE_ID | PEERS            | SCATTERING | WRITTEN_BYTES | READ_BYTES | APPROXIMATE_SIZE(MB) | APPROXIMATE_KEYS |
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
| 1760      | t_1374_   | t_1375_ | 1761      | 4               | 1761, 1762, 1763 | 0          | 0             | 0          | 1                    | 0                |
| 1764      | t_1375_   | t_1376_ | 1765      | 4               | 1765, 1766, 1767 | 0          | 0             | 0          | 1                    | 0                |
| 1768      | t_1376_   | t_1378_ | 1769      | 4               | 1769, 1770, 1771 | 0          | 0             | 0          | 1                    | 0                |
| 1772      | t_1378_   | t_1379_ | 1773      | 4               | 1773, 1774, 1775 | 0          | 0             | 0          | 1                    | 0                |
| 6         | t_1379_   |         | 17        | 4               | 17, 18, 21       | 0          | 214           | 0          | 1                    | 0                |
+-----------+-----------+---------+-----------+-----------------+------------------+------------+---------------+------------+----------------------+------------------+
5 rows in set
Time: 0.011s

What is changed and how it works?

Proposal: xxx

What's Changed:

How it Works:

Related changes

• Need to cherry-pick to the release branch

Check List

Tests

• Unit test
• Manual test (add detailed scripts or steps below)

Side effects

• No

Release note

• Split partition region when adding a new partition

[codecov]

Codecov Report

Merging #16537 into master will decrease coverage by 0.0470%.
The diff coverage is 100.0000%.

@@               Coverage Diff                @@
##             master     #16537        +/-   ##
================================================
- Coverage   80.4155%   80.3685%   -0.0471%     
================================================
  Files           507        507                
  Lines        137303     137127       -176     
================================================
- Hits         110413     110207       -206     
- Misses        18273      18301        +28     
- Partials       8617       8619         +2     

[tiancaiamao]

This makes me confused.
What's the difference between argument pi and tbInfo.GetPartitionInfo(), are't they the same thing?

[crazycs520]

pi will be the added partition information when AddTablePartitions call this function.

[tiancaiamao]

Please add comment for this parameter, otherwise when somebody review this code later in the future, he will have the same question.

[zimulala]

If AddTablePartitions calls this function and fill with partInfo, pi isn't nil, so why we need to add the check of if pi == nil?

[crazycs520]

CreateTableWithInfo will call this function too, then pi will be nil.

[zimulala]

Could we call d.preSplitAndScatter(ctx, tbInfo, tbInfo.GetPartitionInfo()) to handle it in CreateTableWithInfo?

[tiancaiamao]

Rest LGTM

[tiancaiamao]

Please add comment for this parameter, otherwise when somebody review this code later in the future, he will have the same question.

[tiancaiamao]

LGTM

[tiancaiamao]

ref #14478

[zimulala]

LGTM

[sre-bot]

/run-all-tests

[crazycs520]

/run-cherry-picker

[sre-bot]

cherry pick to release-3.0 in PR #17663

[sre-bot]

cherry pick to release-3.1 in PR #17664

[sre-bot]

cherry pick to release-4.0 in PR #17665