Audit, logs and traffic

Dataline is what Synthigy records about itself: the history of your data, the engine's logs, and traffic counters. Where each lives is decided by the bundle:

Bundle	History	Logs and traffic
sqlite	audit.db, beside the database	logs.db, beside the database
postgres	tables in the same Postgres database	logs.db on each node
postgres-clickhouse	ClickHouse	ClickHouse

History in Postgres or audit.db is backed up with the rest of your data. If a part of Dataline cannot run — ClickHouse is down, a file is not writable — the engine keeps serving, the consoles show Dataline as degraded, and the part reconnects on its own when it can.

History

History records every change to the entities you choose: inserts, updates, deletes, links and unlinks, each with who made it, when, and in which request. Switch it on per entity in the data modeling tool (the entity's Audit tab), or for everything with SYNTHIGY_AUDIT_ALL=true.

Attributes classified as secret in the model are recorded as changed, but their values are withheld. Other classifications — pii, phi, internal — are labels for your own policies. History is never pruned automatically.

Read it with POST /history, or through an SDK:

SDK method	Returns
history.getAt(xid, at)	the record as it was at a point in time
history.diff(xid, from, to)	what changed between two points
history.events({recordXid, between})	the change events of one record, or of all
history.timeline({between, groupBy})	events grouped by request, actor or scope
history.since({cursor})	everything after a point, oldest first — for syncing elsewhere

History follows entity and attribute rules: you see history only for entities you may read, without the attributes denied to you (ACCESS.md). A superuser can erase the history of a single record, for example to honour a deletion request.

Logs

Structured logs of the running engine: level, namespace, message, data, host. Read and filter them in the console under Tools → Log cockpit, or over POST /logs with the log:read scope. Levels and per-namespace overrides can be changed at runtime from the cockpit (log:configure scope), without a restart.

The local log file is capped by size and by age — SQLITE_LOGS_MAX_MB and SQLITE_LOGS_RETENTION_DAYS; ClickHouse keeps logs for CLICKHOUSE_LOG_RETENTION_DAYS (ENV.md).

synthigy logs is a different thing: the engine process output — boot messages and crashes — for when the engine is not up to ask.

Traffic

Per-minute counters: operations, subscription streams and a latency histogram, per node, summed across nodes when read. They feed the traffic view of the log cockpit and POST /logs (traffic-stats). No per-request log line is written for them.