10.3. Monitoring

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10.3.1. JMX

	Note
	Most of the monitoring features are only available in the Advanced and Enterprise editions of Neo4j.

In order to be able to continuously get an overview of the health of a Neo4j database, there are different levels of monitoring facilities available.

10.3.1. JMX

How to connect to a Neo4j instance using JMX and JConsole

First, start your embedded database or the Neo4j Server, for instance using

$NEO4j_SERVER_HOME/bin/neo4j start

Now, start JConsole with

$JAVA_HOME/bin/jconsole

Connect to the process running your Neo4j database instance:

Figure 10.1. Connecting JConsole to the Neo4j Java process

Now, beside the MBeans exposed by the JVM, you will see an org.neo4j section in the MBeans tab. Under that, you will have access to all the monitoring information exposed by Neo4j.

Figure 10.2. Neo4j MBeans View

How to connect to the JMX monitoring programmatically

In order to programmatically connect to the Neo4j JMX server, there are some convenience methods in the Neo4j Management component to help you find out the most commonly used monitoring attributes of Neo4j. For instance, the number of node IDs in use can be obtained with code like:

Neo4jManager manager = new Neo4jManager( graphDb.getManagementBean( Kernel.class ) );
long nodeIDsInUse    = manager.getPrimitivesBean.getNumberOfNodeIdsInUse();

Once you have access to this information, you can use it to for instance expose the values to SNMP or other monitoring systems.

Reference of supported JMX MBeans

Table 10.1. MBeans exposed by the Neo4j Kernel

Name	Description
`org.neo4j:instance=kernel#0,name=Memory Mapping`	The status of Neo4j memory mapping
`org.neo4j:instance=kernel#0,name=Locking`	Information about the Neo4j lock status
`org.neo4j:instance=kernel#0,name=Transactions`	Information about the Neo4j transaction manager
`org.neo4j:instance=kernel#0,name=Cache`	Information about the caching in Neo4j
`org.neo4j:instance=kernel#0,name=Configuration`	The configuration parameters used to configure Neo4j
`org.neo4j:instance=kernel#0,name=Primitive count`	Estimates of the numbers of different kinds of Neo4j primitives
`org.neo4j:instance=kernel#0,name=XA Resources`	Information about the XA transaction manager
`org.neo4j:instance=kernel#0,name=Store file sizes`	Information about the sizes of the different parts of the Neo4j graph store
`org.neo4j:instance=kernel#0,name=Kernel`	Information about the Neo4j kernel
`org.neo4j:instance=kernel#0,name=High Availability`	Information an High Availability cluster, if enabled.

Table 10.2. MBean Memory Mapping

Attribute	Description	Type
`MemoryPools`	Get information about each pool of memory mapped regions from store files with memory mapping enabled	String

Table 10.3. MBean Locking

Attribute	Description	Type
`NumberOfAdvertedDeadlocks`	The number of lock sequences that would have lead to a deadlock situation that Neo4j has detected and adverted (by throwing DeadlockDetectedException).	Integer

Table 10.4. MBean Transactions

Attribute	Description	Type
`NumberOfOpenTransactions`	The number of currently open transactions	Integer
`PeakNumberOfConcurrentTransactions`	The highest number of transactions ever opened concurrently	Integer
`NumberOfOpenedTransactions`	The total number started transactions	Integer
`NumberOfCommittedTransactions`	The total number of committed transactionss	Integer

Table 10.5. MBean Cache

Attribute	Description	Type
`CacheType`	The type of cache used by Neo4j	String
`NodeCacheSize`	The number of Nodes currently in cache	Integer
`RelationshipCacheSize`	The number of Relationships currently in cache	Integer
`clear()`	clear all caches	function, void

Table 10.6. MBean Configuration

Attribute	Description	Type
`store_dir`	Relative path for where the Neo4j storage directory is located	String
`rebuild_idgenerators_fast`	Use a quick approach for rebuilding the ID generators. This give quicker recovery time, but will limit the ability to reuse the space of deleted entities.	String
`logical_log`	Relative path for where the Neo4j logical log is located	String
`neostore.propertystore.db.index.keys.mapped_memory`	The size to allocate for memory mapping the store for property key strings	String
`neostore.propertystore.db.strings.mapped_memory`	The size to allocate for memory mapping the string property store	String
`neostore.propertystore.db.arrays.mapped_memory`	The size to allocate for memory mapping the array property store	String
`neo_store`	Relative path for where the Neo4j storage information file is located	String
`neostore.relationshipstore.db.mapped_memory`	The size to allocate for memory mapping the relationship store	String
`neostore.propertystore.db.index.mapped_memory`	The size to allocate for memory mapping the store for property key indexes	String
`create`	Configuration attribute	String
`enable_remote_shell`	Enable a remote shell server which shell clients can log in to	String
`neostore.propertystore.db.mapped_memory`	The size to allocate for memory mapping the property value store	Integer
`neostore.nodestore.db.mapped_memory`	The size to allocate for memory mapping the node store	String
`dir`	Configuration attribute	String

Table 10.7. MBean Primitive count

Attribute	Description	Type
`NumberOfNodeIdsInUse`	An estimation of the number of nodes used in this Neo4j instance	Integer
`NumberOfRelationshipIdsInUse`	An estimation of the number of relationships used in this Neo4j instance	Integer
`NumberOfPropertyIdsInUse`	An estimation of the number of properties used in this Neo4j instance	Integer
`NumberOfRelationshipTypeIdsInUse`	The number of relationship types used in this Neo4j instance	Integer

Table 10.8. MBean XA Resources

Attribute	Description	Type
`XaResources`	Information about all XA resources managed by the transaction manager	String

Table 10.9. MBean Store file sizes

Attribute	Description	Type
`TotalStoreSize`	The total disk space used by this Neo4j instance, in bytes.	Integer
`LogicalLogSize`	The amount of disk space used by the current Neo4j logical log, in bytes.	Integer
`ArrayStoreSize`	The amount of disk space used to store array properties, in bytes.	Integer
`NodeStoreSize`	The amount of disk space used to store nodes, in bytes.	Integer
`PropertyStoreSize`	The amount of disk space used to store properties (excluding string values and array values), in bytes.	Integer
`RelationshipStoreSize`	The amount of disk space used to store relationships, in bytes.	Integer
`StringStoreSize`	The amount of disk space used to store string properties, in bytes.	Integer

Table 10.10. MBean Kernel

Attribute	Description	Type
`ReadOnly`	Whether this is a read only instance.	boolean
`MBeanQuery`	An ObjectName that can be used as a query for getting all management beans for this Neo4j instance.	String
`KernelStartTime`	The time from which this Neo4j instance was in operational mode	Date
`StoreCreationDate`	The time when this Neo4j graph store was created	Date
`StoreId`	An identifier that uniquely identifies this Neo4j graph store	String
`StoreLogVersion`	The current version of the Neo4j store logical log	String
`KernelVersion`	The version of Neo4j	String
`StoreDirectory`	The location where the Neo4j store is located	String

Table 10.11. MBean High Availability

Attribute	Description	Type
`MachineId`	The cluster machine id of this instance	String
`Master`	True, if this Neo4j instance is currently Master in the cluster	boolean
`ConnectedSlaves`	A list of conencted slaves in this cluster	String
`InstancesInCluster`	Information about the other Neo4j instances in this HA cluster	String