backends

backends

Name

SinceVersion 1.2

backends

description

backends 是doris内置的一张系统表，存放在information_schema数据库下。通过backends系统表可以查看当前doris集群中的 BE 节点信息。

backends 表结构为：

MySQL [information_schema]> desc information_schema.backends;
+-----------------------+-------------+------+-------+---------+-------+
| Field                 | Type        | Null | Key   | Default | Extra |
+-----------------------+-------------+------+-------+---------+-------+
| BackendId             | BIGINT      | Yes  | false | NULL    |       |
| Cluster               | VARCHAR(40) | Yes  | false | NULL    |       |
| IP                    | VARCHAR(40) | Yes  | false | NULL    |       |
| HeartbeatPort         | INT         | Yes  | false | NULL    |       |
| BePort                | INT         | Yes  | false | NULL    |       |
| HttpPort              | INT         | Yes  | false | NULL    |       |
| BrpcPort              | INT         | Yes  | false | NULL    |       |
| LastStartTime         | VARCHAR(40) | Yes  | false | NULL    |       |
| LastHeartbeat         | VARCHAR(40) | Yes  | false | NULL    |       |
| Alive                 | VARCHAR(40) | Yes  | false | NULL    |       |
| SystemDecommissioned  | VARCHAR(40) | Yes  | false | NULL    |       |
| ClusterDecommissioned | VARCHAR(40) | Yes  | false | NULL    |       |
| TabletNum             | BIGINT      | Yes  | false | NULL    |       |
| DataUsedCapacity      | BIGINT      | Yes  | false | NULL    |       |
| AvailCapacity         | BIGINT      | Yes  | false | NULL    |       |
| TotalCapacity         | BIGINT      | Yes  | false | NULL    |       |
| UsedPct               | DOUBLE      | Yes  | false | NULL    |       |
| MaxDiskUsedPct        | DOUBLE      | Yes  | false | NULL    |       |
| RemoteUsedCapacity    | BIGINT      | Yes  | false | NULL    |       |
| Tag                   | VARCHAR(40) | Yes  | false | NULL    |       |
| ErrMsg                | VARCHAR(40) | Yes  | false | NULL    |       |
| Version               | VARCHAR(40) | Yes  | false | NULL    |       |
| Status                | VARCHAR(40) | Yes  | false | NULL    |       |
+-----------------------+-------------+------+-------+---------+-------+

backends 系统表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系统表的各个字段类型更加明确，且可以利用 backends 系统表去做过滤、join等操作。

Example

MySQL [information_schema]> select * from  information_schema.backends;
+-----------+-----------------+-----------+---------------+--------+----------+----------+---------------------+---------------------+-------+----------------------+-----------------------+-----------+------------------+---------------+---------------+--------------------+------------------+--------------------+--------------------------+--------+-----------------------------+-------------------------------------------------------------------------------------------------------------------------------+
| BackendId | Cluster         | IP        | HeartbeatPort | BePort | HttpPort | BrpcPort | LastStartTime       | LastHeartbeat       | Alive | SystemDecommissioned | ClusterDecommissioned | TabletNum | DataUsedCapacity | AvailCapacity | TotalCapacity | UsedPct            | MaxDiskUsedPct   | RemoteUsedCapacity | Tag                      | ErrMsg | Version                     | Status                                                                                                                        |
+-----------+-----------------+-----------+---------------+--------+----------+----------+---------------------+---------------------+-------+----------------------+-----------------------+-----------+------------------+---------------+---------------+--------------------+------------------+--------------------+--------------------------+--------+-----------------------------+-------------------------------------------------------------------------------------------------------------------------------+
|     10757 | default_cluster | 127.0.0.1 |          9159 |   9169 |     8149 |     8169 | 2022-11-24 11:16:31 | 2022-11-24 12:02:57 | true  | false                | false                 |        14 |                0 |  941359747073 | 3170529116160 | 70.309064746482065 | 70.3090647465136 |                  0 | {"location" : "default"} |        | doris-0.0.0-trunk-cc9545359 | {"lastSuccessReportTabletsTime":"2022-11-24 12:02:06","lastStreamLoadTime":-1,"isQueryDisabled":false,"isLoadDisabled":false} |
+-----------+-----------------+-----------+---------------+--------+----------+----------+---------------------+---------------------+-------+----------------------+-----------------------+-----------+------------------+---------------+---------------+--------------------+------------------+--------------------+--------------------------+--------+-----------------------------+-------------------------------------------------------------------------------------------------------------------------------+

KeyWords

backends, information_schema

Best Practice