CLUSTER_HARDWARE
集群硬件表 CLUSTER_HARDWARE 提供了集群各实例所在服务器的硬件信息。
USE information_schema;
DESC cluster_hardware;
+-------------+--------------+------+------+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------------+--------------+------+------+---------+-------+
| TYPE | varchar(64) | YES | | NULL | |
| INSTANCE | varchar(64) | YES | | NULL | |
| DEVICE_TYPE | varchar(64) | YES | | NULL | |
| DEVICE_NAME | varchar(64) | YES | | NULL | |
| NAME | varchar(256) | YES | | NULL | |
| VALUE | varchar(128) | YES | | NULL | |
+-------------+--------------+------+------+---------+-------+
6 rows in set (0.00 sec)
字段解释：
TYPE：对应集群信息表information_schema.cluster_info中的TYPE字段，可取值为tidb，pd和tikv。INSTANCE：对应于集群信息表information_schema.cluster_info中的INSTANCE字段。DEVICE_TYPE：硬件类型。目前可以查询的硬件类型有cpu、memory、disk和net。DEVICE_NAME：硬件名。对于不同的DEVICE_TYPE，DEVICE_NAME的取值不同。cpu：硬件名为 cpu。memory：硬件名为 memory。disk：磁盘名。net：网卡名。
NAME：硬件不同的信息名，比如 cpu 有cpu-logical-cores和cpu-physical-cores两个信息名，表示逻辑核心数量和物理核心数量。VALUE：对应硬件信息的值。例如磁盘容量和 CPU 核数。
查询集群 CPU 信息的示例如下：
SELECT * FROM cluster_hardware WHERE device_type='cpu' AND device_name='cpu' AND name LIKE '%cores';
+------+-----------------+-------------+-------------+--------------------+-------+
| TYPE | INSTANCE | DEVICE_TYPE | DEVICE_NAME | NAME | VALUE |
+------+-----------------+-------------+-------------+--------------------+-------+
| tidb | 0.0.0.0:4000 | cpu | cpu | cpu-logical-cores | 16 |
| tidb | 0.0.0.0:4000 | cpu | cpu | cpu-physical-cores | 8 |
| pd | 127.0.0.1:2379 | cpu | cpu | cpu-logical-cores | 16 |
| pd | 127.0.0.1:2379 | cpu | cpu | cpu-physical-cores | 8 |
| tikv | 127.0.0.1:20165 | cpu | cpu | cpu-logical-cores | 16 |
| tikv | 127.0.0.1:20165 | cpu | cpu | cpu-physical-cores | 8 |
+------+-----------------+-------------+-------------+--------------------+-------+
6 rows in set (0.03 sec)