[Improvement]Add schema table backend_active_tasks

[wangbo]

Proposed changes

mysql [information_schema]>desc information_schema.backend_active_tasks;
+---------------------------+--------------+------+-------+---------+-------+
| Field                     | Type         | Null | Key   | Default | Extra |
+---------------------------+--------------+------+-------+---------+-------+
| BE_ID                     | BIGINT       | Yes  | false | NULL    |       |
| FE_HOST                   | VARCHAR(256) | Yes  | false | NULL    |       |
| QUERY_ID                  | VARCHAR(256) | Yes  | false | NULL    |       |
| TASK_TIME_MS              | BIGINT       | Yes  | false | NULL    |       |
| TASK_CPU_TIME_MS          | BIGINT       | Yes  | false | NULL    |       |
| SCAN_ROWS                 | BIGINT       | Yes  | false | NULL    |       |
| SCAN_BYTES                | BIGINT       | Yes  | false | NULL    |       |
| BE_PEAK_MEMORY_BYTES      | BIGINT       | Yes  | false | NULL    |       |
| CURRENT_USED_MEMORY_BYTES | BIGINT       | Yes  | false | NULL    |       |
| SHUFFLE_SEND_BYTES        | BIGINT       | Yes  | false | NULL    |       |
| SHUFFLE_SEND_ROWS         | BIGINT       | Yes  | false | NULL    |       |
+---------------------------+--------------+------+-------+---------+-------+
11 rows in set (0.00 sec)

[doris-robot]

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[wangbo]

run buildall

[doris-robot]

TeamCity be ut coverage result:
Function Coverage: 35.38% (8558/24189)
Line Coverage: 27.14% (69494/256065)
Region Coverage: 26.37% (36049/136708)
Branch Coverage: 23.21% (18424/79392)
Coverage Report: http://coverage.selectdb-in.cc/coverage/36c7ec685979d5434cca1252204cae04982a8ce4_36c7ec685979d5434cca1252204cae04982a8ce4/report/index.html

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.

[wangbo]

run buildall

[doris-robot]

TeamCity be ut coverage result:
Function Coverage: 35.36% (8555/24193)
Line Coverage: 27.14% (69513/256100)
Region Coverage: 26.36% (36069/136815)
Branch Coverage: 23.22% (18441/79430)
Coverage Report: http://coverage.selectdb-in.cc/coverage/7a691175753ea691f211e633f4d2d8e74581882b_7a691175753ea691f211e633f4d2d8e74581882b/report/index.html

[wangbo]

run buildall

[doris-robot]

TeamCity be ut coverage result:
Function Coverage: 35.36% (8555/24193)
Line Coverage: 27.14% (69511/256114)
Region Coverage: 26.36% (36068/136820)
Branch Coverage: 23.21% (18434/79434)
Coverage Report: http://coverage.selectdb-in.cc/coverage/4239eefdf5fd4b736f46a2ff6afda02a29b4b4bb_4239eefdf5fd4b736f46a2ff6afda02a29b4b4bb/report/index.html

[github-actions]

PR approved by at least one committer and no changes requested.

[morningman]

Please update the document

[morningman]

LGTM