Legacy HBase client-side metrics

This page describes a set of client-side metrics that has been replaced with built-in client-side metrics. This page is maintained as a reference for any developers who still use the legacy metrics.

We recommend using the built-in client-side metrics described on the Client-side metrics overview instead of the legacy metrics described on this page.

Enable metrics

This information is provided for customers who are using the legacy metrics. To enable the newer, built-in client-side metrics, see Set up client-side metrics.

The Cloud Bigtable HBase client for Java used Dropwizard Metrics to collect and report client-side metrics. Because collecting metrics can add a very small amount of latency (single-digit microseconds) to each request, metrics were not enabled by default. The following sections explain how to enable the legacy client-side metrics.

Use the Log4j reporter

The simplest way to enable the legacy client-side metrics is to add the following line to your Log4j configuration file:

log4j.category.com.google.cloud.bigtable.metrics=DEBUG

This configuration setting turns on metrics collection and logs Bigtable metrics with an SLF4J logger.

Use other reporters

You can use other types of reporters by updating your application's code. For example, here is a reporter that sends metrics to a Graphite server:

Graphite pickledGraphite = new PickledGraphite(new InetSocketAddress("graphite.example.com", 2004));
DropwizardMetricRegistry registry = new DropwizardMetricRegistry();
GraphiteReporter reporter =
    GraphiteReporter.forRegistry(registry.getRegistry())
        .convertRatesTo(TimeUnit.SECONDS)
        .convertDurationsTo(TimeUnit.MILLISECONDS)
        .filter(MetricFilter.ALL)
        .build(pickledGraphite);
reporter.start(1, TimeUnit.MINUTES);
BigtableClientMetrics.setMetricRegistry(registry);

Dropwizard Metrics provides reporters for JMX, console logging, SLF4J, and CSV. There are also a variety of third-party reporters available.

Available metrics

This section describes the metrics that are available when the legacy HBase client-side metrics are enabled. Each metric has one of the following types:

• Counter: A cumulative count per Java virtual machine (JVM).
• Meter: Count information plus throughput information (a count per the last minute, 5 minutes, or 15 minutes)
• Timer: Meter information plus latency information (such as median, mean, and 95th percentile)

Only certain metrics are collected for each type of request. See "Example: Metrics for a Put request" for an example of the metrics that are collected during a Put request.

Channel-level metrics

General RPC metrics

Data method metrics

Data method metrics are collected for the following data methods:

• ReadRows: Implements gets and scans.
• MutateRow: Implements puts and deletes.
• MutateRows: Implements bulk writes.
• CheckAndMutateRow: Implements HBase's checkAnd* methods.
• ReadModifyWrite: Implements HBase's Append and Increment methods.
• SampleRowKeys: Retrieves region information that is used for MapReduce operations.

Bulk metrics

Bulk metrics are provided for methods that return more than one response, such as a bulk write.

Bigtable table metrics

Converting Bigtable objects to HBase objects can add to the latency of a request. The following timers can be correlated with the specified *.operation.latency timers to measure the cost of the conversion.

Example: Metrics for a Put request

When client-side metrics are enabled, the following metrics are collected for a successful Put request that is not retried:

• Counter: google-cloud-bigtable.grpc.rpc.active
• Meter: google-cloud-bigtable.grpc.rpc.performed
• Timer: google-cloud-bigtable.grpc.method.MutateRow.operation.latency
• Timer: google-cloud-bigtable.table.put.latency

Collecting these metrics adds approximately 1 microsecond (1/1000 of a millisecond) to the Put operation. The overall Put operation could be as fast as 2 to 3 milliseconds, assuming that the operation includes about 1 KB of data.