[[cluster-nodes-stats]]
== Nodes Stats

[float]
=== Nodes statistics

The cluster nodes stats API allows to retrieve one or more (or all) of
the cluster nodes statistics.

[source,js]
--------------------------------------------------
curl -XGET 'http://localhost:9200/_cluster/nodes/stats'
curl -XGET 'http://localhost:9200/_cluster/nodes/nodeId1,nodeId2/stats'

# simplified
curl -XGET 'http://localhost:9200/_nodes/stats'
curl -XGET 'http://localhost:9200/_nodes/nodeId1,nodeId2/stats'
--------------------------------------------------

The first command retrieves stats of all the nodes in the cluster. The
second command selectively retrieves nodes stats of only `nodeId1` and
`nodeId2`. All the nodes selective options are explained
<<cluster-nodes,here>>.

By default, `indices` stats are returned. With options for `indices`,
`os`, `process`, `jvm`, `network`, `transport`, `http`, `fs`, and
`thread_pool`. For example:

[horizontal]
`indices`:: 
	Indices stats about size, document count, indexing and
	deletion times, search times, field cache size , merges and flushes

`fs`:: 
	File system information, data path, free disk space, read/write
	stats

`http`:: 
	HTTP connection information

`jvm`:: 
	JVM stats, memory pool information, garbage collection, buffer
	pools

`network`:: 
	TCP information

`os`:: 
	Operating system stats, load average, cpu, mem, swap

`process`:: 
	Process statistics, memory consumption, cpu usage, open
	file descriptors

`thread_pool`:: 
	Statistics about each thread pool, including current
	size, queue and rejected tasks

`transport`:: 
	Transport statistics about sent and received bytes in
	cluster communication

`clear`:: 
	Clears all the flags (first). Useful, if you only want to
	retrieve specific stats.

[source,js]
--------------------------------------------------
# return indices and os
curl -XGET 'http://localhost:9200/_nodes/stats?os=true'
# return just os and process
curl -XGET 'http://localhost:9200/_nodes/stats?clear=true&os=true&process=true'
# specific type endpoint
curl -XGET 'http://localhost:9200/_nodes/process/stats'
curl -XGET 'http://localhost:9200/_nodes/10.0.0.1/process/stats'
# or, if you like the other way
curl -XGET 'http://localhost:9200/_nodes/stats/process'
curl -XGET 'http://localhost:9200/_nodes/10.0.0.1/stats/process'
--------------------------------------------------

The `all` flag can be set to return all the stats.

[float]
=== Field data statistics

From 0.90, you can get information about field data memory usage on node
level or on index level.

[source,js]
--------------------------------------------------
# Node Stats
curl localhost:9200/_nodes/stats/indices/fielddata/field1,field2?pretty

# Indices Stat
curl localhost:9200/_stats/fielddata/field1,field2?pretty

# You can use wildcards for field names
curl localhost:9200/_stats/fielddata/field*?pretty
curl localhost:9200/_nodes/stats/indices/fielddata/field*?pretty
--------------------------------------------------