README.md

Tracing

Tracing is implemented via the tracing crate. This page describes the spans used by the client and the fields emitted on each of the spans.

See the pipeline test application for an example showing how to configure tracing with a local Jaeger instance. This crate ships with a small example that uses docker-compose to run a local Jaeger instance.

Spans

This table shows the spans emitted by the client. The Partial Trace column describes whether the span will appear when only the partial-tracing feature flag is enabled.

Name	Description	Partial Trace
redis_command	The top level span used for all redis commands.	x
prepare_args	Time spent checking and preparing arguments.
queued	Time spent waiting in the in-memory queue before being sent to the server. Pipelining and backpressure settings can drastically affect this.
write_command	Time spent routing and writing a command.
wait_for_response	Time spent waiting on a response from the server, starting from when the first byte is fed to the socket and ending when the response has been decoded.	x
parse_pubsub	Time spent parsing a publish-subscribe message.

Tracing levels for the two tracing features can be configured separately through the TracingConfig.

Events

Name	Description
backpressure	Emitted when a command hits backpressure due to too many in-flight commands.

Fields

Name	Description
client_id	The ID of the client instance (client.id()).
cmd	The redis command name.
req_size	The size (in bytes) of the command's arguments.
res_size	The size (in bytes) of the command's response.
num_args	The number of arguments being sent to the server.
buf_len	The length of the in-memory command queue.
pipelined	Whether or not a command was pipelined.
flush	Whether or not the socket was flushed while sending a command.
channel	The channel on which a pubsub message was received.
duration_ms	The duration of a pause, in milliseconds, of a backpressure event.