Current situation of Doris is that the cluster is balanced, but the disks of a backend may be unbalanced.
for example, backend A have two disks: disk1 and disk2, disk1's usage is 98%, but disk2's usage is only 40%.
disk1 is unable to take more data, therefore only one disk of backend A can take new data,
the available write throughput of backend A is only half of its ability, and we can not resolve this through load or
partition rebalance now.
So we introduce disk rebalancer, disk rebalancer is different from other rebalancer(load or partition)
which take care of cluster-wide data balancing. it takes care about backend-wide data balancing.
[For more details see #8550](https://github.com/apache/incubator-doris/issues/8550)
* [improvement](show) Support that user can use show data skew statement instead of admin
This PR mainly do two things:
1. Support that user can use show data skew statement instead of admin
2. Fix fe ut failed caused by pr [improvement](rewrite) Make RewriteDateLiteralRule to be compatible with mysql #7876 and pr [feature-wip](iceberg) Step1: Support create Iceberg external table #7391
Co-authored-by: caiconghui1 <caiconghui1@jd.com>
1. Fix bug of UNKNOWN Operation Type 91
2. Support using resource_tag property of user to limit the usage of BE
3. Add new FE config `disable_tablet_scheduler` to disable tablet scheduler.
4. Add documents for resource tag.
5. Modify the default value of FE config `default_db_data_quota_bytes` to 1PB.
6. Add a new BE config `disable_compaction_trace_log` to disable the trace log of compaction time cost.
7. Modify the default value of BE config `remote_storage_read_buffer_mb` to 16MB
8. Fix `show backends` results error
9. Add new BE config `external_table_connect_timeout_sec` to set the timeout when connecting to odbc and mysql table.
10. Modify issue template to enable blank issue, for release note or other specific usage.
11. Fix a bug in alpha_row_set split_range() function.
SHOW DATA SKEW FROM tbl PARTITION(p1)
to view the data distribution of a specified partition
```
mysql> admin show data skew from tbl1 partition(tbl1);
+-----------+-------------+-------+---------+
| BucketIdx | AvgDataSize | Graph | Percent |
+-----------+-------------+-------+---------+
| 0 | 0 | | 100.00% |
+-----------+-------------+-------+---------+
1 row in set (0.01 sec)
```
Also modify the result of `admin show replica distribution`, add replica size distribution
```
mysql> admin show replica distribution from tbl1 partition(tbl1);
+-----------+------------+-------------+----------+------------+-----------+-------------+
| BackendId | ReplicaNum | ReplicaSize | NumGraph | NumPercent | SizeGraph | SizePercent |
+-----------+------------+-------------+----------+------------+-----------+-------------+
| 10002 | 1 | 0 | > | 100.00% | | 100.00% |
+-----------+------------+-------------+----------+------------+-----------+-------------+
```
This PR is to support grammar like the following: INSTALL PLUGIN FROM [source] [PROPERTIES("KEY"="VALUE", ...)]
user can set md5sum="xxxxxxx", so we don't need to provide a md5 uri.
