Exposing system metrics (Enterprise)

In production systems, monitoring of applications is crucial, and that includes databases as well. Memgraph allows tracking information about transactions, query latencies, snapshot recovery latencies, triggers, bolt messages, indexes, streams, and many more using an HTTP server.

Exposing metrics is a Memgraph Enterprise feature and therefore needs a valid Memgraph Enterprise license key. After successfully entering the license key, Memgraph needs to be restarted in order to start the metrics HTTP server.

Configuring the HTTP endpoint

The default address and port for the metrics server is 0.0.0.0:9091, and can be configured using configuration flags --metrics-address and --metrics-port. If you need help changing the configuration follow the how-to guide.

System metrics

All system metrics measuring different parts of the system can be divided into three different types:

• Gauge - a single value of some variable in the system (e.g. memory usage)
• Counter (uint64_t) - a value that can be incremented or decremented (e.g. number of active transactions in the system)
• Histogram (uint64_t) - distribution of measured values (e.g. certain percentile of query latency on N measured queries)

General metrics

Name	Type	Description
vertex_count	Gauge (uint64_t)	Number of nodes stored in the system.
edge_count	Gauge (uint64_t)	Number of relationships stored in the system.
average_degree	Gauge (double)	Average number of relationships of a single node.
memory_usage	Gauge (uint64_t)	Amount of RAM used reported by the OS (in bytes).
disk_usage	Gauge (uint64_t)	Amount of disk space used by the data directory (in bytes).

Index metrics

Name	Type	Description
ActiveLabelIndices	Counter	Number of active label indices in the system.
ActiveLabelPropertyIndices	Counter	Number of active label property indices in the system.

Operator metrics

Before a Cypher query is executed, it is converted into an internal form suitable for execution, known as a query plan. A query plan is a tree-like data structure describing a pipeline of operations that will be performed on the database in order to yield the results for a given query. Every node within a plan is known as a logical operator and describes a particular operation.

Name	Type	Description
OnceOperator	Counter	Number of times Once operator was used.
CreateNodeOperator	Counter	Number of times CreateNode operator was used.
CreateExpandOperator	Counter	Number of times CreateExpand operator was used.
ScanAllOperator	Counter	Number of times ScanAll operator was used.
ScanAllByLabelOperator	Counter	Number of times ScanAllByLabel operator was used.
ScanAllByLabelPropertyRangeOperator	Counter	Number of times ScanAllByLabelPropertyRange operator was used.
ScanAllByLabelPropertyValueOperator	Counter	Number of times ScanAllByLabelPropertyValue operator was used.
ScanAllByLabelPropertyOperator	Counter	Number of times ScanAllByLabelProperty operator was used.
ScanAllByLabelIdOperator	Counter	Number of times ScanAllByLabelId operator was used.
ExpandOperator	Counter	Number of times Expand operator was used.
ExpandVariableOperator	Counter	Number of times ExpandVariable operator was used.
ConstructNamedPathOperator	Counter	Number of times ConstructNamedPath operator was used.
FilterOperator	Counter	Number of times Filter operator was used.
ProduceOperator	Counter	Number of times Produce operator was used.
DeleteOperator	Counter	Number of times Delete operator was used.
SetPropertyOperator	Counter	Number of times SetProperty operator was used.
SetPropertiesOperator	Counter	Number of times SetProperties operator was used.
SetLabelsOperator	Counter	Number of times SetLabels operator was used.
RemovePropertyOperator	Counter	Number of times RemoveProperty operator was used.
RemoveLabelsOperator	Counter	Number of times RemoveLabels operator was used.
EdgeUniquenessFilterOperator	Counter	Number of times EdgeUniquenessFilter operator was used.
EmptyResultOperator	Counter	Number of times EmptyResult operator was used.
AccumulateOperator	Counter	Number of times Accumulate operator was used.
AggregateOperator	Counter	Number of times Aggregate operator was used.
SkipOperator	Counter	Number of times Skip operator was used.
LimitOperator	Counter	Number of times Limit operator was used.
OrderByOperator	Counter	Number of times OrderBy operator was used.
MergeOperator	Counter	Number of times Merge operator was used.
OptionalOperator	Counter	Number of times Optional operator was used.
UnwindOperator	Counter	Number of times Unwind operator was used.
DistinctOperator	Counter	Number of times Distinct operator was used.
UnionOperator	Counter	Number of times Union operator was used.
CartesianOperator	Counter	Number of times Cartesian operator was used.
CallProcedureOperator	Counter	Number of times CallProcedureOperator operator was used.
ForeachOperator	Counter	Number of times Foreach operator was used.
EvaluatePatternFilterOperator	Counter	Number of times EvaluatePatternFilter operator was used.
ApplyOperator	Counter	Number of times Apply operator was used.

Query metrics

Name	Type	Description
QueryExecutionLatency_us_50p	Histogram	Query execution latency in microseconds (50th percentile).
QueryExecutionLatency_us_90p	Histogram	Query execution latency in microseconds (90th percentile).
QueryExecutionLatency_us_99p	Histogram	Query execution latency in microseconds (99th percentile).

Query type metrics

Name	Type	Description
ReadQuery	Counter	Number of read-only queries executed.
WriteQuery	Counter	Number of write-only queries executed.
ReadWriteQuery	Counter	Number of read-write queries executed.

Session metrics

Name	Type	Description
ActiveSessions	Counter	Number of active connections.
ActiveBoltSessions	Counter	Number of active Bolt connections.
ActiveTCPSessions	Counter	Number of active TCP connections.
ActiveSSLSessions	Counter	Number of active SSL connections.
ActiveWebSocketSessions	Counter	Number of active websocket connections.
BoltMessages	Counter	Number of Bolt messages sent.

Snapshot metrics

Name	Type	Description
SnapshotCreationLatency_us_50p	Histogram	Snapshot creation latency in microseconds (50th percentile).
SnapshotCreationLatency_us_90p	Histogram	Snapshot creation latency in microseconds (90th percentile)-
SnapshotCreationLatency_us_99p	Histogram	Snapshot creation latency in microseconds (99th percentile).
SnapshotRecoveryLatency_us_50p	Histogram	Snapshot recovery latency in microseconds (50th percentile).
SnapshotRecoveryLatency_us_90p	Histogram	Snapshot recovery latency in microseconds (90th percentile).
SnapshotRecoveryLatency_us_99p	Histogram	Snapshot recovery latency in microseconds (99th percentile).

Stream metrics

Name	Type	Description
StreamsCreated	Counter	Number of streams created.
MessagesConsumed	Counter	Number of consumed streamed messages.

Transaction metrics

Name	Type	Description
ActiveTransactions	Counter	Number of active transactions.
CommitedTransactions	Counter	Number of committed transactions.
RollbackedTransactions	Counter	Number of rollbacked transactions.
FailedQuery	Counter	Number of times executing a query failed (either during parse time or runtime).

Trigger metrics

Name	Type	Description
TriggersCreated	Counter	Number of Triggers created.
TriggersExecuted	Counter	Number of Triggers executed.

Example response

If there aren't any modifying configurations, by sending a GET request to localhost:9091 in the local Memgraph build will result in a response similar to the one below.

{
    "General": {
        "average_degree": 0.0,
        "disk_usage": 1417846,
        "edge_count": 0,
        "memory_usage": 36937728,
        "vertex_count": 0
    },
    "Index": {
        "ActiveLabelIndices": 0,
        "ActiveLabelPropertyIndices": 0
    },
    "Operator": {
        "AccumulateOperator": 0,
        "AggregateOperator": 0,
        "ApplyOperator": 0,
        "CallProcedureOperator": 0,
        "CartesianOperator": 0,
        "ConstructNamedPathOperator": 0,
        "CreateExpandOperator": 0,
        "CreateNodeOperator": 0,
        "DeleteOperator": 0,
        "DistinctOperator": 0,
        "EdgeUniquenessFilterOperator": 0,
        "EmptyResultOperator": 0,
        "EvaluatePatternFilterOperator": 0,
        "ExpandOperator": 0,
        "ExpandVariableOperator": 0,
        "FilterOperator": 0,
        "ForeachOperator": 0,
        "LimitOperator": 0,
        "MergeOperator": 0,
        "OnceOperator": 0,
        "OptionalOperator": 0,
        "OrderByOperator": 0,
        "ProduceOperator": 0,
        "RemoveLabelsOperator": 0,
        "RemovePropertyOperator": 0,
        "ScanAllByIdOperator": 0,
        "ScanAllByLabelOperator": 0,
        "ScanAllByLabelPropertyOperator": 0,
        "ScanAllByLabelPropertyRangeOperator": 0,
        "ScanAllByLabelPropertyValueOperator": 0,
        "ScanAllOperator": 0,
        "SetLabelsOperator": 0,
        "SetPropertiesOperator": 0,
        "SetPropertyOperator": 0,
        "SkipOperator": 0,
        "UnionOperator": 0,
        "UnwindOperator": 0
    },
    "Query": {
        "QueryExecutionLatency_us_50p": 0,
        "QueryExecutionLatency_us_90p": 0,
        "QueryExecutionLatency_us_99p": 0
    },
    "QueryType": {
        "ReadQuery": 0,
        "ReadWriteQuery": 0,
        "WriteQuery": 0
    },
    "Session": {
        "ActiveBoltSessions": 0,
        "ActiveSSLSessions": 0,
        "ActiveSessions": 0,
        "ActiveTCPSessions": 0,
        "ActiveWebSocketSessions": 0,
        "BoltMessages": 0
    },
    "Snapshot": {
        "SnapshotCreationLatency_us_50p": 4860,
        "SnapshotCreationLatency_us_90p": 4860,
        "SnapshotCreationLatency_us_99p": 4860,
        "SnapshotRecoveryLatency_us_50p": 628,
        "SnapshotRecoveryLatency_us_90p": 628,
        "SnapshotRecoveryLatency_us_99p": 628
    },
    "Stream": {
        "MessagesConsumed": 0,
        "StreamsCreated": 0
    },
    "Transaction": {
        "ActiveTransactions": 0,
        "CommitedTransactions": 0,
        "FailedQuery": 0,
        "RollbackedTransactions": 0
    },
    "Trigger": {
        "TriggersCreated": 0,
        "TriggersExecuted": 0
    }
}