cat thread pool

thread_pool 命令展示了集群中每一个节点的线程池的统计信息。默认情况下返回所有线程池的 actinve（活跃的），queue（队列中的）和 reject（拒绝的）的统计信息。

% curl 192.168.56.10:9200/_cat/thread_pool
0EWUhXe bulk                0 0 0
0EWUhXe fetch_shard_started 0 0 0
0EWUhXe fetch_shard_store   0 0 0
0EWUhXe flush               0 0 0
0EWUhXe force_merge         0 0 0
0EWUhXe generic             0 0 0
0EWUhXe get                 0 0 0
0EWUhXe index               0 0 0
0EWUhXe listener            0 0 0
0EWUhXe management          1 0 0
0EWUhXe refresh             0 0 0
0EWUhXe search              0 0 0
0EWUhXe snapshot            0 0 0
0EWUhXe warmer              0 0 0

第一列是节点名

node_name
0EWUhXe

第二列是线程池名

name
bulk
fetch_shard_started
fetch_shard_store
flush
force_merge
generic
get
index
listener
management
refresh
search
snapshot
warmer

接下来的三列是所有线程池的 actinve（活跃的），queue（队列中的）和 reject（拒绝的）的统计信息。

active queue rejected
     0     0        0
     0     0        0
     0     0        0
     0     0        0
     0     0        0
     0     0        0
     0     0        0
     0     0        0
     0     0        0
     1     0        0
     0     0        0
     0     0        0
     0     0        0
     0     0        0

该 cat thread pool API 接受一个 thread_pool_patternsURL 参数，该参数指定一个逗号分隔的正则表达式列表以匹配线程池名称。

% curl 'localhost:9200/_cat/thread_pool/generic?v&h=id,name,active,rejected,completed'
id                     name    active rejected completed
0EWUhXeBQtaVGlexUeVwMg generic      0        0        70

在这里，建议线程池的统计信息展示 host，active，rejected 和 completed 列。

所有 built-in thread pools 和自定义的线程池都是可用的。

线程池字段

对于每个线程池来说，您可以通过使用表哥中的字段名来获得详细说明。

Field Name（字段名）	Alias（别名）	Description（描述）
`type`	`t`	The current (*) type of thread pool (`fixed` or `scaling`)
`active`	`a`	The number of active threads in the current thread pool
`size`	`s`	The number of threads in the current thread pool
`queue`	`q`	The number of tasks in the queue for the current thread pool
`queue_size`	`qs`	The maximum number of tasks permitted in the queue for the current thread pool
`rejected`	`r`	The number of tasks rejected by the thread pool executor
`largest`	`l`	The highest number of active threads in the current thread pool
`completed`	`c`	The number of tasks completed by the thread pool executor
`min`	`mi`	The configured minimum number of active threads allowed in the current thread pool
`max`	`ma`	The configured maximum number of active threads allowed in the current thread pool
`keep_alive`	`k`	The configured keep alive time for threads

其它字段

除了每个线程池的详细说明之外，它也可以方便理解线程池的内部。同样的，您可以请求响应的节点的其它详细说明。（例如 ip）

Field Name（字段名）	Alias（别名）	Description（描述）
`node_id`	`id`	The unique node ID
`ephemeral_id`	`eid`	The ephemeral node ID
`pid`	`p`	The process ID of the running node
`host`	`h`	The hostname for the current node
`ip`	`i`	The IP address for the current node
`port`	`po`	The bound transport port for the current node