Metrics
EventStoreDB collects metrics in prometheus format, available on the /metrics endpoint. Promethus can be configured to scrape this endpoint directly. The metrics are configured in metricsconfig.json.
NOTE
/metrics does not yet contain metrics for Projections and Persistent Subscriptions. To view these in Prometheus it is still recommended to use the Prometheus exporter
Metrics Reference
Caches
Cache hits and misses
EventStoreDB tracks cache hits/misses metrics for stream-info and chunk caches.
| Time Series | Type | Description |
|---|---|---|
eventstore_cache_hits_misses{cache=<CACHE_NAME>,kind=<"hits"|"misses">} | Counter | Total hits/misses on CACHE_NAME cache |
Example Configuration:
"CacheHitsMisses": {
"StreamInfo": true,
"Chunk": false
}
Example Output:
# TYPE eventstore_cache_hits_misses counter
eventstore_cache_hits_misses{cache="stream-info",kind="hits"} 104329 1688157489545
eventstore_cache_hits_misses{cache="stream-info",kind="misses"} 117 1688157489545
Dynamic Cache Resources
Certain caches that EventStoreDB uses are dynamic in nature i.e. their capacity scales up/down during their lifetime. EventStoreDB records metrics for resources being used by each such dynamic cache.
| Time Series | Type | Description |
|---|---|---|
eventstore_cache_resources_bytes{cache=<CACHE_NAME>,kind=<"capacity"|"size">} | Gauge | Current capacity/size of CACHE_NAME cache in bytes |
eventstore_cache_resources_entries{cache=<CACHE_NAME>,kind="count"} | Gauge | Current number of entries in CACHE_NAME cache |
Example Configuration:
"CacheResources": true
Example Output:
# TYPE eventstore_cache_resources_bytes gauge
# UNIT eventstore_cache_resources_bytes bytes
eventstore_cache_resources_bytes{cache="LastEventNumber",kind="capacity"} 50000000 1688157491029
eventstore_cache_resources_bytes{cache="LastEventNumber",kind="size"} 15804 1688157491029
# TYPE eventstore_cache_resources_entries gauge
# UNIT eventstore_cache_resources_entries entries
eventstore_cache_resources_entries{cache="LastEventNumber",kind="count"} 75 1688157491029
Checkpoints
| Time Series | Type | Description |
|---|---|---|
eventstore_checkpoints{name=<CHECKPOINT_NAME>,read="non-flushed"} | Gauge | Value for CHECKPOINT_NAME checkpoint |
Example Configuration:
"Checkpoints": {
"Replication": true,
"Chaser": false,
"Epoch": false,
"Index": false,
"Proposal": false,
"Truncate": false,
"Writer": false,
"StreamExistenceFilter": false
}
Example Output:
# TYPE eventstore_checkpoints gauge
eventstore_checkpoints{name="replication",read="non-flushed"} 613363 1688054162478
Events
These metrics track events written to and read from the server, including reads from caches.
| Time Series | Type | Description |
|---|---|---|
eventstore_io_bytes{activity="read"} | Counter | Event bytes read |
eventstore_io_events{activity=<"read"|"written">} | Counter | Events read/written |
Example Configuration:
"Events": {
"Read": false,
"Written": true
}
Example Output:
# TYPE eventstore_io_events counter
# UNIT eventstore_io_events events
eventstore_io_events{activity="written"} 320 1687963622074
Gossip
Measures the round trip latency and processing time of gossip. Usually a node pushes new gossip to other nodes periodically or when its view of the cluster changes. Sometimes nodes pull gossip from each other if there is a suspected network problem.
Gossip Latency
| Time Series | Type | Description |
|---|---|---|
eventstore_gossip_latency_seconds_bucket{activity="pull-from-peer",status=<"successful"|"failed">,le=<DURATION>} | Histogram | Number of gossips pulled from peers with latency less than or equal to DURATION in seconds |
eventstore_gossip_latency_seconds_bucket{activity="push-to-peer",status=<"successful"|"failed">,le=<DURATION>} | Histogram | Number of gossips pushed to peers with latency less than or equal to DURATION in seconds |
Gossip Processing
| Time Series | Type | Description |
|---|---|---|
eventstore_gossip_processing_duration_seconds_bucket{activity="push-from-peer",status=<"successful"|"failed">,le=<DURATION>} | Histogram | Number of gossips pushed from peers that took less than or equal to DURATION in seconds to process |
eventstore_gossip_processing_duration_seconds_bucket{activity="request-from-peer",status=<"successful"|"failed">,le=<DURATION>} | Histogram | Number of gossip requests from peers that took less than or equal to DURATION in seconds to process |
eventstore_gossip_processing_duration_seconds_bucket{activity="request-from-grpc-client",status=<"successful"|"failed">,le=<DURATION>} | Histogram | Number of gossip requests from gRPC clients that took less than or equal to DURATION in seconds to process |
eventstore_gossip_processing_duration_seconds_bucket{activity="request-from-http-client",status=<"successful"|"failed">,le=<DURATION>} | Histogram | Number of gossip requests from HTTP clients that took less than or equal to DURATION in seconds to process |
Example Configuration:
"Gossip": {
"PullFromPeer": false,
"PushToPeer": true,
"ProcessingPushFromPeer": false,
"ProcessingRequestFromPeer": false,
"ProcessingRequestFromGrpcClient": false,
"ProcessingRequestFromHttpClient": false
}
Example Output:
# TYPE eventstore_gossip_latency_seconds histogram
# UNIT eventstore_gossip_latency_seconds seconds
eventstore_gossip_latency_seconds_bucket{activity="push-to-peer",status="successful",le="0.005"} 8 1687972306948
Incoming Grpc Calls
| Time Series | Type | Description |
|---|---|---|
eventstore_current_incoming_grpc_calls | Gauge | Inflight gRPC calls i.e. gRPC requests that have started on the server but not yet stopped |
eventstore_incoming_grpc_calls{kind="total"} | Counter | Total gRPC requests served |
eventstore_incoming_grpc_calls{kind="failed"} | Counter | Total gRPC requests failed |
eventstore_incoming_grpc_calls{kind="unimplemented"} | Counter | Total gRPC requests made to unimplemented methods |
eventstore_incoming_grpc_calls{kind="deadline-exceeded"} | Counter | Total gRPC requests for which deadline have exceeded |
Example Configuration:
"IncomingGrpcCalls": {
"Current": true,
"Total": false,
"Failed": true,
"Unimplemented": false,
"DeadlineExceeded": false
}
Example Output:
# TYPE eventstore_current_incoming_grpc_calls gauge
eventstore_current_incoming_grpc_calls 1 1687963622074
# TYPE eventstore_incoming_grpc_calls counter
eventstore_incoming_grpc_calls{kind="failed"} 1 1687962877623
Client protocol gRPC methods
In addition, EventStoreDB also records metrics for each of client protocol gRPC methods : StreamRead, StreamAppend, StreamBatchAppend, StreamDelete and StreamTombstone. They are grouped together according to the mapping defined in the configuration.
| Time Series | Type | Description |
|---|---|---|
eventstore_grpc_method_duration_seconds_bucket{activity=<LABEL>,status="successful"|"failed",le=<DURATION>} | Histogram | Number of LABEL gRPC requests that took less than or equal to DURATION in seconds to process |
Example Configuration:
"GrpcMethods": {
"StreamAppend": "append",
"StreamBatchAppend": "append",
// leaving label as blank will disable metric collection
"StreamRead": "",
"StreamDelete": "",
"StreamTombstone": ""
}
Example Output:
# TYPE eventstore_grpc_method_duration_seconds histogram
# UNIT eventstore_grpc_method_duration_seconds seconds
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="1E-06"} 0 1688157491029
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="1E-05"} 0 1688157491029
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="0.0001"} 129 1688157491029
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="0.001"} 143 1688157491029
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="0.01"} 168 1688157491029
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="0.1"} 169 1688157491029
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="1"} 169 1688157491029
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="10"} 169 1688157491029
eventstore_grpc_method_duration_seconds_bucket{activity="append",status="successful",le="+Inf"} 169 1688157491029
Kestrel
| Time Series | Type | Description |
|---|---|---|
eventstore_kestrel_connections | Gauge | Number of open kestrel connections |
Example Configuration:
"Kestrel": {
"ConnectionCount": true
}
Example Output:
# TYPE eventstore_kestrel_connections gauge
eventstore_kestrel_connections 1 1688070655500
Process
EventStoreDB collects key metrics about the running process.
| Time Series | Type | Description |
|---|---|---|
eventstore_proc_up_time{pid=<PID>} | Counter | Time in seconds this process has been running for. PID is process Id of EventStoreDB process |
eventstore_proc_cpu | Gauge | Process CPU usage |
eventstore_proc_thread_count | Gauge | Current number of threadpool threads (ThreadPool.ThreadCount) |
eventstore_proc_thread_pool_pending_work_item_count | Gauge | Current number of items that are queued to be processed by threadpool threads (ThreadPool.PendingWorkItemCount) |
eventstore_proc_contention_count | Counter | Total number of times there was contention when trying to take monitor's lock (Monitor.LockContentionCount) |
eventstore_proc_exception_count | Counter | Total number of exceptions thrown |
eventstore_gc_time_in_gc | Gauge | Percentage of CPU time spent collecting garbage during last garbage collection |
eventstore_gc_heap_size_bytes | Gauge | Heap size in bytes |
eventstore_gc_heap_fragmentation | Gauge | Percentage of heap fragmentation during last garbage collection |
eventstore_gc_total_allocated | Counter | Total allocated bytes over the lifetime of this process |
eventstore_gc_pause_duration_max_seconds{range=<RANGE>} | RecentMax | Recent maximum garbage collection pause in seconds. This measures the times that the execution engine is paused for GC |
eventstore_gc_generation_size_bytes{generation=<"gen0"|"gen1"|"gen2"|"loh">} | Gauge | Size of each generation in bytes |
eventstore_gc_collection_count{generation=<"gen0"|"gen1"|"gen2">} | Counter | Number of garbage collections from each generation |
eventstore_proc_mem_bytes{kind=<"working-set"|"paged-bytes"|"virtual-bytes">} | Gauge | Size in bytes of the working set, paged or virtual memory |
eventstore_disk_io_bytes{activity=<"read"|"written">} | Counter | Number of bytes read from/written to the disk |
eventstore_disk_io_operations{activity=<"read"|"written">} | Counter | Number of OS read/write operations issued to the disk |
Example Configuration:
"Process": {
"UpTime": false,
"Cpu": false,
"MemWorkingSet": false,
"MemPagedBytes": false,
"MemVirtualBytes": false,
"ThreadCount": true,
"ThreadPoolPendingWorkItemCount": false,
"LockContentionCount": true,
"ExceptionCount": false,
"Gen0CollectionCount": false,
"Gen1CollectionCount": false,
"Gen2CollectionCount": false,
"Gen0Size": false,
"Gen1Size": false,
"Gen2Size": false,
"LohSize": false,
"TimeInGc": false,
"GcPauseDuration": true,
"HeapSize": false,
"HeapFragmentation": false,
"TotalAllocatedBytes": false,
"DiskReadBytes": false,
"DiskReadOps": false,
"DiskWrittenBytes": false,
"DiskWrittenOps": false
}
Example Output:
# TYPE eventstore_proc_thread_count gauge
eventstore_proc_thread_count 15 1688070655500
# TYPE eventstore_proc_contention_count counter
eventstore_proc_contention_count 297 1688147136862
# TYPE eventstore_gc_pause_duration_max_seconds gauge
# UNIT eventstore_gc_pause_duration_max_seconds seconds
eventstore_gc_pause_duration_max_seconds{range="16-20 seconds"} 0.0485873 1688147136862
Queues
EventStoreDB uses various queues for asynchronous processing for which it also collects different metrics. In addition, EventStoreDB allows users to group queues and monitor them as a unit.
| Time Series | Type | Description |
|---|---|---|
eventstore_queue_busy_seconds{queue=<QUEUE_GROUP>} | Counter | Total time spent processing in seconds, averaged across the queues in the QUEUE_GROUP. The rate of this metric is therefore the average busyness of the group during the period (from 0-1 s/s) |
eventstore_queue_queueing_duration_max_seconds{name=<QUEUE_GROUP>,range=<RANGE>} | RecentMax | Recent maximum time in seconds for which any item was queued in queues belonging to the QUEUE_GROUP. This is essentially the length of the longest queue in the group in seconds |
eventstore_queue_processing_duration_seconds_bucket{message_type=<TYPE>,queue=<QUEUE_GROUP>,le=<DURATION>} | Histogram | Number of messages of type TYPE processed by QUEUE_GROUP group that took less than or equal to DURATION in seconds |
QueueLabels setting within metricsconfig.json can be used to group queues, based on regex which gets matched on queue names, and label them for metrics reporting. Capture groups are also supported. Message types can be grouped in the same way in the MessageTypes setting in metricsconfig.json.
NOTE
Enabling Queues.Processing can cause a lot more time series to be generated, according to the QueueLabels and MessageTypes configuration.
Example Configuration:
Queues": {
"Busy": true,
"Length": true,
"Processing": false
}
"QueueLabels": [
{
"Regex": "StorageReaderQueue #.*",
"Label": "Readers"
},
{
"Regex": ".*",
"Label": "Others"
}
]
Example Output:
# TYPE eventstore_queue_busy_seconds counter
# UNIT eventstore_queue_busy_seconds seconds
eventstore_queue_busy_seconds{queue="Readers"} 1.04568158125 1688157491029
eventstore_queue_busy_seconds{queue="Others"} 0 1688157491029
# TYPE eventstore_queue_queueing_duration_max_seconds gauge
# UNIT eventstore_queue_queueing_duration_max_seconds seconds
eventstore_queue_queueing_duration_max_seconds{name="Readers",range="16-20 seconds"} 0.06434454 1688157489545
eventstore_queue_queueing_duration_max_seconds{name="Others",range="16-20 seconds"} 0 1688157489545
Status
EventStoreDB tracks the current status of the Node role as well as progress of Index, and Scavenge processes.
| Time Series | Type | Description |
|---|---|---|
eventstore_statuses{name=<NAME>,status=<STATUS>} | Gauge | Number of seconds since the 1970 epoch when NAME most recently had the status STATUS |
For a given NAME, the current status can be determined by taking the max of all the time series with that name.
Index can have one of the following statuses:
- Opening (loading/verifying the PTables)
- Rebuilding (indexing previously written records on start up)
- Initializing (initializing any other parts of the index e.g. StreamExistenceFilter on start up)
- Merging
- Scavenging
- Idle
Scavenge can have one of the following statuses:
- Accumulation
- Calculation
- Chunk Execution
- Chunk Merging
- Index Execution
- Cleaning
- Idle
Node can be one of the node roles.
Example Configuration:
"Statuses": {
"Index": true,
"Node": false,
"Scavenge": false
}
Example Output:
# TYPE eventstore_checkpoints gauge
eventstore_statuses{name="Index",status="Idle"} 1688054162 1688054162477
Storage Writer
| Time Series | Type | Description |
|---|---|---|
eventstore_writer_flush_size_max{range=<RANGE>} | RecentMax | Recent maximum flush size in bytes |
eventstore_writer_flush_duration_max_seconds{range=<RANGE>} | RecentMax | Recent maximum flush duration in seconds |
Example Configuration:
"Writer": {
"FlushSize": true,
"FlushDuration": false
}
Example Output:
# TYPE eventstore_writer_flush_size_max gauge
eventstore_writer_flush_size_max{range="16-20 seconds"} 410 1688056823193
System
| Time Series | Type | Description |
|---|---|---|
eventstore_sys_load_avg{period=<"1m"|"5m"|"15m">} | Gauge | Average system load in last 1, 5, and 15 minutes. This metric is only available for Unix-like systems |
eventstore_sys_cpu | Gauge | Current CPU usage in percentage. This metric is unavailable for Unix-like systems |
eventstore_sys_mem_bytes{kind=<"free"|"total">} | Gauge | Current free/total memory in bytes |
eventstore_sys_disk_bytes{disk=<MOUNT_POINT>,kind=<"used"|"total">} | Gauge | Current used/total bytes of disk mounted at MOUNT_POINT |
Example Configuration:
"System": {
"Cpu": false,
"LoadAverage1m": false,
"LoadAverage5m": false,
"LoadAverage15m": false,
"FreeMem": false,
"TotalMem": false,
"DriveTotalBytes": false,
"DriveUsedBytes": true
}
Example Output:
# TYPE eventstore_sys_disk_bytes gauge
# UNIT eventstore_sys_disk_bytes bytes
eventstore_sys_disk_bytes{disk="/home",kind="used"} 38947205120 1688070655500
Metric Types
Common types
Please refer to Prometheus documentation for explanation of common metric types (Gauge, Counter and Histogram).
RecentMax
A gauge whose value represents the maximum out of a set of recent measurements. It's purpose is to capture spikes that would otherwise have fallen in-between scrapes.
NOTE
The ExpectedScrapeIntervalSeconds setting within metricsconfig.json can be used to control the size of the window that the max is calculated over. It represents the expected interval between scrapes by a consumer such as Prometheus. It can only take specific values: 0, 1, 5, 10 or multiples of 15.
Setting the expected scape interval correctly ensures that spikes in the time series will be captured by at least one scrape and at most two.
Example Output: Following metric is reported when ExpectedScrapeIntervalSeconds is set to 15 seconds
# TYPE eventstore_writer_flush_size_max gauge
eventstore_writer_flush_size_max{range="16-20 seconds"} 1854 1688070655500
In above example, maximum reported is 1854. It is not a maximum measurement in last 15s but rather maximum measurement in last 16 to last 20 seconds i.e. the maximum measurement could have been recorded in last 16s, last 17s, ...., upto last 20s.