BACKENDS | SelectDB

`backends`

Name

backends

description

表函数，生成 backends 临时表，可以查看当前 doris 集群中的 BE 节点信息。

该函数用于 from 子句中。

syntax

backends()

backends() 表结构：

mysql> desc function backends();
+-------------------------+---------+------+-------+---------+-------+
| Field                   | Type    | Null | Key   | Default | Extra |
+-------------------------+---------+------+-------+---------+-------+
| BackendId               | BIGINT  | No   | false | NULL    | NONE  |
| Host                    | TEXT    | No   | false | NULL    | NONE  |
| HeartbeatPort           | INT     | No   | false | NULL    | NONE  |
| BePort                  | INT     | No   | false | NULL    | NONE  |
| HttpPort                | INT     | No   | false | NULL    | NONE  |
| BrpcPort                | INT     | No   | false | NULL    | NONE  |
| LastStartTime           | TEXT    | No   | false | NULL    | NONE  |
| LastHeartbeat           | TEXT    | No   | false | NULL    | NONE  |
| Alive                   | BOOLEAN | No   | false | NULL    | NONE  |
| SystemDecommissioned    | BOOLEAN | No   | false | NULL    | NONE  |
| TabletNum               | BIGINT  | No   | false | NULL    | NONE  |
| DataUsedCapacity        | BIGINT  | No   | false | NULL    | NONE  |
| AvailCapacity           | BIGINT  | No   | false | NULL    | NONE  |
| TotalCapacity           | BIGINT  | No   | false | NULL    | NONE  |
| UsedPct                 | DOUBLE  | No   | false | NULL    | NONE  |
| MaxDiskUsedPct          | DOUBLE  | No   | false | NULL    | NONE  |
| RemoteUsedCapacity      | BIGINT  | No   | false | NULL    | NONE  |
| Tag                     | TEXT    | No   | false | NULL    | NONE  |
| ErrMsg                  | TEXT    | No   | false | NULL    | NONE  |
| Version                 | TEXT    | No   | false | NULL    | NONE  |
| Status                  | TEXT    | No   | false | NULL    | NONE  |
| HeartbeatFailureCounter | INT     | No   | false | NULL    | NONE  |
| NodeRole                | TEXT    | No   | false | NULL    | NONE  |
+-------------------------+---------+------+-------+---------+-------+
23 rows in set (0.002 sec)

backends() tvf 展示出来的信息基本与 show backends 语句展示出的信息一致，但是 backends() tvf 的各个字段类型更加明确，且可以利用 tvf 生成的表去做过滤、join 等操作。

对 backends() tvf 信息展示进行了鉴权，与 show backends 行为保持一致，要求用户具有 ADMIN/OPERATOR 权限。

example

mysql> select * from backends()\G
*************************** 1. row ***************************
              BackendId: 10002
                   Host: 10.xx.xx.90
          HeartbeatPort: 9053
                 BePort: 9063
               HttpPort: 8043
               BrpcPort: 8069
          LastStartTime: 2023-06-15 16:51:02
          LastHeartbeat: 2023-06-15 17:09:58
                  Alive: 1
   SystemDecommissioned: 0
              TabletNum: 21
       DataUsedCapacity: 0
          AvailCapacity: 5187141550081
          TotalCapacity: 7750977622016
                UsedPct: 33.077583202570978
         MaxDiskUsedPct: 33.077583202583881
     RemoteUsedCapacity: 0
                    Tag: {"location" : "default"}
                 ErrMsg: 
                Version: doris-0.0.0-trunk-4b18cde0c7
                 Status: {"lastSuccessReportTabletsTime":"2023-06-15 17:09:02","lastStreamLoadTime":-1,"isQueryDisabled":false,"isLoadDisabled":false}
HeartbeatFailureCounter: 0
               NodeRole: mix
1 row in set (0.038 sec)

keywords

backends

Outer 组合器 CATALOGS