Eventstore – Extra Statistics Option on Persistent Subscription – Where is it?

When creating a new persistent subscription in EventStore, there are many options to configure. The extra statistics option was a peculiar one, once enabled there is no indication on what it is doing and where you can see the extra statistics. My previous post about viewing more detailed information on an EventStore persistent subscription likely gave away the answer, the json result of the info link for the persistent subscription has a connections collection. With extra statistics enabled you will see statistics gathered for each connection.

To get to the more detailed information about a persistent subscription and view the extra statistics for the connections use the following url format:
http://localhost:2113/subscriptions/{stream}/{group}/info

Here is an example result with the extra statics option enabled:

{
"links": [
{
"href": "http://localhost:2113/subscriptions/%24ce-SomeStream/Testing/info",
"rel": "detail"
},
{
"href": "http://localhost:2113/subscriptions/%24ce-SomeStream/Testing/replayParked",
"rel": "replayParked"
}
],
"config": {
"resolveLinktos": true,
"startFrom": 0,
"messageTimeoutMilliseconds": 10000,
"extraStatistics": true,
"maxRetryCount": 10,
"liveBufferSize": 500,
"bufferSize": 500,
"readBatchSize": 20,
"preferRoundRobin": true,
"checkPointAfterMilliseconds": 1000,
"minCheckPointCount": 10,
"maxCheckPointCount": 500,
"maxSubscriberCount": 10,
"namedConsumerStrategy": "RoundRobin"
},
"eventStreamId": "$ce-SomeStream",
"groupName": "Testing",
"status": "Behind",
"averageItemsPerSecond": 40.0,
"parkedMessageUri": "http://localhost:2113/streams/%24persistentsubscription-%24ce-SomeStream::Testing-parked",
"getMessagesUri": "http://localhost:2113/subscriptions/%24ce-SomeStream/Testing/1",
"totalItemsProcessed": 967,
"countSinceLastMeasurement": 28,
"lastProcessedEventNumber": 944,
"lastKnownEventNumber": 1459,
"readBufferCount": 493,
"liveBufferCount": 0,
"retryBufferCount": 0,
"totalInFlightMessages": 10,
"connections": [
{
"from": "10.10.10.1:17998",
"username": "admin",
"averageItemsPerSecond": 40.0,
"totalItemsProcessed": 967,
"countSinceLastMeasurement": 28,
"extraStatistics": [
{
"key": "Mean",
"value": 16
},
{
"key": "Median",
"value": 6
},
{
"key": "Fastest",
"value": 5
},
{
"key": "Quintile 1",
"value": 5
},
{
"key": "Quintile 2",
"value": 6
},
{
"key": "Quintile 3",
"value": 6
},
{
"key": "Quintile 4",
"value": 6
},
{
"key": "Quintile 5",
"value": 14
},
{
"key": "90%",
"value": 65
},
{
"key": "95%",
"value": 76
},
{
"key": "99%",
"value": 109
},
{
"key": "99.5%",
"value": 110
},
{
"key": "99.9%",
"value": 111
},
{
"key": "Highest",
"value": 111
}
],
"availableSlots": 0,
"inFlightMessages": 10
}
]
}