DSE Advanced Replication metrics

Collect metrics on each source node to review the current status of that node in the source cluster. A working source and destination configuration is required to use the metrics feature. See Getting started.

Ensure JMX access

Metrics are stored in the DataStax Enterprise JMX system. JMX access is required.

For production, DataStax recommends authenticating JMX users, see Configuring JMX authentication.
Use these steps to enable local JMX access. Localhost access is useful for test and development.
1. On the source node, edit cassandra-env.sh and enable local JMX:
  JVM_OPTS="$JVM_OPTS -Djava.rmi.server.hostname=localhost" LOCAL_JMX=yes
2. On the source node, stop and restart DataStax Enterprise to recognize the local JMX change.

Display metrics on the command line

Use the dse advrep command line tool to display metrics on the command line. Ensure that the source node meets the command line prerequisites.

On the source node:

dse advrep --jmx-port 7199 metrics list

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|Group         |Type               |Count|
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|Tables        |MessagesDelivered  |1002 |
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|ReplicationLog|CommitLogsToConsume|1    |
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|Tables        |MessagesReceived   |1002 |
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|ReplicationLog|MessageAddErrors   |0    |
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|ReplicationLog|CommitLogsDeleted  |0    |
------------------------------------------

-------------------------------------------------------------------------------------------------------------------------------------------------
|Group         |Type                 |Count|RateUnit     |MeanRate            |FifteenMinuteRate    |OneMinuteRate      |FiveMinuteRate         |
-------------------------------------------------------------------------------------------------------------------------------------------------
|ReplicationLog|MessagesAdded        |1002 |events/second|0.012688461014514603|9.862886141388435E-39|2.964393875E-314   |2.322135514219019E-114 |
-------------------------------------------------------------------------------------------------------------------------------------------------
|ReplicationLog|MessagesDeleted      |0    |events/second|0.0                 |0.0                  |0.0                |0.0                    |
-------------------------------------------------------------------------------------------------------------------------------------------------
|ReplicationLog|MessagesAcknowledged |1002 |events/second|0.012688456391385135|9.86403600116801E-39 |2.964393875E-314   |2.3230339468969963E-114|
-------------------------------------------------------------------------------------------------------------------------------------------------
|ReplicationLog|CommitLogMessagesRead|16873|events/second|0.21366497971804438 |0.20580430240786005  |0.39126032533612265|0.2277227124698431     |
-------------------------------------------------------------------------------------------------------------------------------------------------

-------------------------------------
|Group       |Type            |Value|
-------------------------------------
|Transmission|AvailablePermits|30000|
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Accessing the metrics

Use JMX to access the metrics. Any JMX tool, such as jconsole, can access the MBeans for advanced replication. The port listed above, 7199, is used with the hostname or IP address:

Use JMX to access the metrics

Choose the MBeans tab and find com.datastax.bdp.advrep.v2.metrics in the left-hand navigation frame:

Choose the MBeans tab

The example shown here displays the attributes for com.datastax.bdp.advrep.v2.metrics:type=ReplicationLog,name=MessagesAdded.

Performance metrics

Metrics are exposed as JMX MBeans under the com.datastax.bdp.advrep.v2.metrics path and are logically divided into main groups. Each group refers to an architecture component. Metrics types are:

Counter: A simple incrementing and decrementing 64-bit integer.
Meter: Measures the rate at which a set of events occur.
Histogram: Measures the distribution of values in a stream of data.
Timer: A histogram of the duration of a type of event and a meter of the rate of its occurrence.
Gauge: A gauge is an instantaneous measurement of a value.

Metrics are available for the following groups:

ReplicationLog
Transmission
AdvancedReplicationHub-[destinationId]-metrics

Metrics are also available per table:

Performance metrics per table

Descriptions of each metric is provided.

Metrics for DSE 5.0 (V1) are still present; see the DSE 5.0 documentation for those metrics.

`ReplicationLog`

Metrics for the `ReplicationLog` group
Metric name	Description	Metric type
`MessagesAdded`	The number of messages that were added to the replication log, and the rate that the messages were added, per replica.	Meter
`MessagesAcknowledged`	The number of messages that were acknowledged (and removed) from the replication log. Acknowledgement can be 1 or 1+n if errors occur.	Meter
`MessagesDeleted`	The number of messages that were deleted from the replication log, including invalid messages and messages that were removed after a channel truncate operation.	Meter
`MessageAddErrors`	The number of errors that occurred when adding a message to the replication log.	Counter
`CommitLogsToConsume`	The number of commit logs that need to be consumed that have advanced replication messages.	Counter
`CommitLogMessagesRead`	The number of commit log messages added to the replication log. The commit log messages are read if a message pertains to a source table that has collection enabled.	Meter
`CommitLogMessagesDeleted`	The number of commit log messages deleted from the commit log after adding to the replication log. Like `CommitLogMessagesRead`, this metric only pertains to messages in tables that are enabled for advanced replication.	Meter

Transmission

Metrics for the Transmission group
Metric name	Description	Metric type
`AvailablePermits`	The current number of available global permits for transmission.	Gauge

`AdvancedReplicationHub-[destinationName]-metrics`

Metrics for the AdvancedReplicationHub-[destinationName]-metrics group are provided automatically by the DSE Java driver.

Metrics provided automatically by the DSE Java driver

Incomplete examples of per-destination-metrics
Metric name	Metric type
known-hosts	Counter
connected-to	Counter
open-connections	Counter
requests-timer	Timer
connection-errors	Counter
write-timeouts	Counter
read-timeouts	Counter
unavailables	Counter
other-errors	Counter
retries	Counter
ignores	Counter

For details, see the DSE Java driver documentation.

Performance metrics per table

Use JMX to find performance metrics per table, look under the com.datastax.bdp.advrep.v2.metrics tab in the left-hand navigation frame for Tables, select a table and inspect the metrics:

Use JMX to find performance metrics per table

For example, to access the MessagesReceived metric for the table sensor_readings in the keyspace demo look at the following path:

com.datastax.bdp.advrep.v2.metrics:type=Tables,scope=demo.sensor_readings,name=MessagesReceived

The following metrics are provided per table:

Provided metrics
Metric name	Description	Metric type
`MessagesReceived`	The number of messages received from the source cluster for this table.	Counter
`MessagesDelivered`	The number of messages for the source table that were replicated to the destination.	Counter
`MessagesDeleted`	The number of messages that were deleted from the replication log, including invalid messages and messages that were removed after a channel truncate operation.	Counter