store/helper: fill data in the information.tidb_hot_table for partitioned table (#14331)

[sre-bot]

cherry-pick #14331 to release-3.0

---

What problem does this PR solve?

INFORMATION.TIDB_HOT_TABLE should take the partitioned table into consideration.

What is changed and how it works?

A partitioned table is not handled properly in tidb_hot_table.
After this change, we can get the correct information:

mysql> select * from tidb_hot_regions;
+----------+----------+---------+------------------+------------+-----------+-------+----------------+--------------+------------+
| TABLE_ID | INDEX_ID | DB_NAME | TABLE_NAME       | INDEX_NAME | REGION_ID | TYPE  | MAX_HOT_DEGREE | REGION_COUNT | FLOW_BYTES |
+----------+----------+---------+------------------+------------+-----------+-------+----------------+--------------+------------+
|       23 |     NULL | mysql   | stats_histograms | NULL       |        48 | read  |              3 |            0 |     211478 |
|       25 |     NULL | mysql   | stats_buckets    | NULL       |        52 | write |              3 |            0 |      93013 |
|      151 |     NULL | test    | sbtest3(p1)      | NULL       |      1156 | write |              3 |            0 |      93013 |
|      150 |     NULL | test    | sbtest3(p0)      | NULL       |      1152 | write |              3 |            0 |      93013 |
+----------+----------+---------+------------------+------------+-----------+-------+----------------+--------------+------------+
4 rows in set (0.08 sec)

Note, 151 and 150 are both belong to sbtest3, and the table name column is displayed as sbtest3(p1) and sbtest3(p0) to indicate they are partitions.

Check List

Tests

• Manual test (add detailed scripts or steps below)

Mock the data is hard, the old code is not really unit tested.
I use a real tikv cluster and check the result.
B.T.W, a bug is fixed, pd returns something like this:

{
  "as_peer": {
    "1": {
      "total_flow_bytes": 190434.14973961416,
      "regions_count": 3,
      "statistics": [
        {
          "store_id": 1,
          "region_id": 1156,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 50956.69507956832,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:54.147084771+08:00",
          "Version": 127
        },
        {
          "store_id": 1,
          "region_id": 1152,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 93013.72966004584,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:51.146018185+08:00",
          "Version": 126
        },
        {
          "store_id": 1,
          "region_id": 52,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 46463.725,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:48.507062772+08:00",
          "Version": 13
        }
      ]
    },
    "4": {
      "total_flow_bytes": 190434.14973961416,
      "regions_count": 3,
      "statistics": [
        {
          "store_id": 4,
          "region_id": 1156,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 50956.69507956832,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:54.147078479+08:00",
          "Version": 127
        },
        {
          "store_id": 4,
          "region_id": 1152,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 93013.72966004584,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:51.146019774+08:00",
          "Version": 126
        },
        {
          "store_id": 4,
          "region_id": 52,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 46463.725,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:48.507064672+08:00",
          "Version": 13
        }
      ]
    },
    "5": {
      "total_flow_bytes": 190434.14973961416,
      "regions_count": 3,
      "statistics": [
        {
          "store_id": 5,
          "region_id": 1156,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 50956.69507956832,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:54.147083702+08:00",
          "Version": 127
        },
        {
          "store_id": 5,
          "region_id": 1152,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 93013.72966004584,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:51.146020767+08:00",
          "Version": 126
        },
        {
          "store_id": 5,
          "region_id": 52,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 46463.725,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:48.507065709+08:00",
          "Version": 13
        }
      ]
    }
  },
  "as_leader": {
    "1": {
      "total_flow_bytes": 0,
      "regions_count": 0,
      "statistics": []
    },
    "4": {
      "total_flow_bytes": 143970.42473961416,
      "regions_count": 2,
      "statistics": [
        {
          "store_id": 4,
          "region_id": 1156,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 50956.69507956832,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:54.147078479+08:00",
          "Version": 127
        },
        {
          "store_id": 4,
          "region_id": 1152,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 93013.72966004584,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:51.146019774+08:00",
          "Version": 126
        }
      ]
    },
    "5": {
      "total_flow_bytes": 46463.725,
      "regions_count": 1,
      "statistics": [
        {
          "store_id": 5,
          "region_id": 52,
          "hot_degree": 3,
          "AntiCount": 1,
          "kind": 0,
          "flow_bytes": 46463.725,
          "flow_keys": 0,
          "RollingBytesRate": null,
          "last_update_time": "2020-01-03T16:10:48.507065709+08:00",
          "Version": 13
        }
      ]
    }
  }
}

From the PD result we can see flow_bytes is a float, not uint. @disksing @nolouch

"flow_bytes": 50956.69507956832

Related changes

• Need to cherry-pick to the release branch

Release note

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

[sre-bot]

/run-all-tests

[jackysp]

LGTM

[zz-jason]

LGTM