backends

`backends`

Name

SinceVersion dev

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  |
| Cluster                 | TEXT   | No   | false | NULL    | NONE  |
| IP                      | TEXT   | No   | false | NULL    | NONE  |
| HostName                | 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                   | TEXT   | No   | false | NULL    | NONE  |
| SystemDecommissioned    | TEXT   | No   | false | NULL    | NONE  |
| ClusterDecommissioned   | TEXT   | 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  |
+-------------------------+--------+------+-------+---------+-------+
26 rows in set (0.04 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。

example

mysql> select * from backends()\G
*************************** 1. row ***************************
              BackendId: 10022
                Cluster: default_cluster
                     IP: 10.16.10.14
               HostName: 10.16.10.14
          HeartbeatPort: 9159
                 BePort: 9169
               HttpPort: 8149
               BrpcPort: 8169
          LastStartTime: 2023-03-24 14:37:00
          LastHeartbeat: 2023-03-27 20:25:35
                  Alive: true
   SystemDecommissioned: false
  ClusterDecommissioned: false
              TabletNum: 21
       DataUsedCapacity: 0
          AvailCapacity: 787460558849
          TotalCapacity: 3169589592064
                UsedPct: 75.155756416520319
         MaxDiskUsedPct: 75.155756416551881
     RemoteUsedCapacity: 0
                    Tag: {"location" : "default"}
                 ErrMsg:
                Version: doris-0.0.0-trunk-8de51f96f3
                 Status: {"lastSuccessReportTabletsTime":"2023-03-27 20:24:55","lastStreamLoadTime":-1,"isQueryDisabled":false,"isLoadDisabled":false}
HeartbeatFailureCounter: 0
               NodeRole: mix
1 row in set (0.03 sec)

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