Observability Glossary

Span

You can think of a span like a log with a start time and end time within a distributed trace.

For example, if a user makes a request to a web application that then calls a database and an external API, each of these interactions is captured as a separate span. Each span contains details about the operation (the url of the external API or the query ran on the database) as well as the start time and end time of each of the operations. This enables developers to understand the performance and behavior of each individual part of the system.

In modern applications, you'd use OpenTelemetry to instrument your application. With OpenTelemetry, you can automatically instrument common IO operations and add custom spans for your custom business logic. This enables you to visualize the flow of requests and pinpoint any areas that require attention, such as slow database queries or third-party service dependencies.

Explore related concepts

Trace

A trace is a single request or transaction and all the subsequent events as it moves through a distributed system. This data typically includes information about the components involved in the transaction, as well as the timing and outcome of each interaction.

Observability

Observability is the ability to understand how your application is working and behaving in production through telemetry data (logs, metrics, traces, wide events, etc.). It enables you detect, diagnose and resolve issues in your app before they impact your users and become problems.

Distributed Tracing

Distributed Tracing is a method for tracking the flow of requests through your application. It enables you to follow the journey of a request as it travels across multiple services, so you can see where things might be going wrong.