ApacheHttpClient Connection Pool

This section describes the types, names, and meanings of ApacheHttpClient connection pool metrics collected by APM.

**Table 1** ApacheHttpClient connection pool metrics
Category	Metric	Name	Description	Unit	Data Type	Default Aggregation Mode
Connection pool (connectionPool: statistics about ApacheHttpclient connections in different states)	poolId	Connection Pool ID	ApacheHttpclient connection pool ID	-	ENUM	LAST
	available	Idle Connections	Number of idle connections in the connection pool	-	INT	SUM
	leased	Occupied Connections	Number of connections occupied	-	INT	SUM
	max	Max. Connections	Maximum number of connections in the connection pool	-	INT	MAX
	pending	Pending Connections	Number of pending connections in the connection pool	-	INT	SUM
Connection pool route (collectionPoolRoute: APM counts connection statistics by pool route.)	poolId	Connection Pool ID	ApacheHttpClient connection pool ID	-	ENUM	LAST
	route	Route	Routing information of the connection pool	-	ENUM	LAST
	available	Idle Connections	Number of idle connections in the connection pool	-	INT	SUM
	leased	Occupied Connections	Number of connections occupied	-	INT	SUM
	max	Max. Connections	Maximum number of connections in the connection pool	-	INT	MAX
	pending	Pending Connections	Number of pending connections in the connection pool	-	INT	SUM