Capturing System Metrics

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This section explains how to capture system metrics for analysis. Metrics such as First Time to Audio and TTS Stream Latency are useful for pinpointing performance issues and understanding system timings.

To capture system metrics:

1 Edit the vocalos-node.xml file, located in the /opt/VocalOS/Server/server/nodeserver/conf directory.

2 Search for MetricManager in the file.

3 Uncomment out the file metrics handler node XML.

4 Save the changes.

5 Restart the server.

The following example shows the file metrics handler node in the vocalos-node.xml file.

<map>

</map>

</node>

The handlers available to you are implementations of the net.vocalocity.common.util.jmx.metricImetricHandler interface which the MetricManager will dispatch metric events to for processing. The handler in the example writes metrics to a file, based on the configuration settings. The following table explains the configuration settings.

Parameter	Description
pattern	A regex-based pattern for filtering metrics. The default is .* which is a wildcard regex. You can specify vocalos.tts.* to specify you want only TTS-related metrics.
append	Indicates whether to append or truncate it on startup
separator	Indicates what separator you want to use between fields
dateFormat	A valid java.util.DateFormat date format specifier

Example Metric

The following example shows what a metric entry might look like.

10.19.2004 13:57:21.034,111882788-bk8cy-1098208619326-a304b6249b8ff00799668c126bfddd73,tts,null,vocalos.tss.stream_latency,40

The following table explains each column of the metric.

Column	Description
10/19/2004 13:57:21.034	Date
111882788.....bfddd73	Session ID
tts	Category
null	Metric type, or null if not specified
vocalos.tts.stream_latency	Metric name
40	Metric value, or string value of metric if complex

To capture only tts metrics, enter a regexp such as:

.*tts.*

Available Metrics

The following table shows the metrics that are available.

Category	Name	Description
Telephony	vocalos.telephony.time_to_first_audio	The time between answer to when the first audio packet is played
Telephony	vocalos.telephony.time_to_answer	The time from OFFERED until we issue an ANSWER
Telephony	vocalos.telephony.audio_play_count	The number of audio plays we issue for a channel
Telephony	vocalos.telephony.call_summary	A metric that is dispatched to summarize activity across channels on a system
TTS	vocalos.tts.stream_latency	The amount of time to stream audio
Runtime	vocalos.runtime.snapshot	A periodic snapshot of vital system data such as threads, and memory

Metric Handlers

The following table describes the metric handlers that are available.

Class	Description
FileMetricHandler	Writes metrics to a file
JDBCMetricHandler	Writes metrics to a JDBC-compliant database
JMXMetricHandler	Sends metrics as a JMX notification
Log4JMetricHandler	Writes metrics as a log entry using log4j

All metric handlers are located in the following package:

net.vocalocity.common.util.jmx.metric.handler

Log4J Metric Handler

You can customize the log4j metric handler to capture different categories and logging levels. The following table describes the key values.

Key	Description
category	Changes the log4j category to use when logging metrics. The default value is Metric.
level	Changes the log4j severity level to use when logging metrics. The default value is Debug.

The following example shows how to customize the log handler for the log4j metric handler.

<map>

</map>

</node>