Core concepts

A quick glossary of the concepts you’ll see across Stream Trace.

JetStream concepts

• Stream - a JetStream stream: a server-managed, persistent log of messages captured from one or more subjects. Stream Trace lists every stream you have access to, along with its configuration and stats.
• Consumer - a view over a stream that tracks delivery and acknowledgement for a subscriber. Consumers are where lag and backlog show up.
• Subject - the address a message is published to (e.g. orders.created). Streams capture subjects, and consumers can filter to a subset of them.
• Sequence - the monotonic position of a message within a stream. Stream Trace uses sequences to address individual messages and to bound searches.
• Acknowledgement (ACK / NAK / TERM) - how a consumer reports the outcome of processing a message: acknowledged, negatively-acknowledged (redeliver), or terminated (give up).

Stream Trace concepts

• Message index - Stream Trace’s background indexer records message metadata (subject, sequence, timestamp, size) so listing and filtering stay fast on large streams. See Indexing & performance.
• Payload index - an optional, deeper index of message contents that powers full-text and JSON path search. It is off by default; enable it with ST_PAYLOAD_INDEXING_ENABLED=true. See Searching messages.
• DLQ case - a dead-letter “case” Stream Trace builds when JetStream emits an terminal advisory after a message reaches MaxDeliver or is terminated. Cases are captured via an advisory stream.
• Trace - a set of related message observations correlated by a trace ID (read from headers like Nats-Trace-Id). See Throughput & tracing.
• Throughput sample - a periodic snapshot of stream and consumer rates that Stream Trace stores to chart throughput and detect trends over time.

Access concepts

• Team - a group of users. Streams are owned by teams, and most permissions are granted per team.
• Stream ownership - the mapping of a stream to the team(s) that can access it. See Teams & multi-tenancy.
• Role - a named bundle of permissions, scoped either globally or to a team. See Roles & permissions.
• Audit event - a record of a security event or write action (publish, replay, DLQ remediation, admin change, login) with the actor, time, and outcome. Ordinary reads are not audited.