Operational data about your account, held read-only in the system catalog, e.g. system.access.audit, system.billing.usage and lineage. Users need SELECT plus USE CATALOG and USE SCHEMA.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains System tables in context, with comparison tables and the common traps.
Terms in this definition
- Chat message roles
Labels on chat messages: instructions go under system, the person's input under user, the model's previous answers under assistant, and results returned by a called tool under tool (or function).
- Catalog
The first level of Unity Catalog's
catalog.schema.tablenaming and the primary boundary for isolating data. Privileges granted on a catalog flow down to every schema and object it contains. - system.access.audit
Records audit events for workspaces in your region, in a system table still in Public Preview. You get 365 days of retention free.
- system.billing.usage
The system table to build cost queries on, covering billable usage for the whole account. Records usually appear within 12 hours.
- SELECT
A DML command in SQL used to retrieve rows from one table or several.
- Usage privileges
USE CATALOGandUSE SCHEMA: alone they expose no data, yet reaching any object inside requires them, so owners of catalogs and schemas can cap what table owners share.
Related terms
- Billing tables
The system tables that show charges:
system.billing.usagelists billable use in DBUs andsystem.billing.list_priceslists the prices. Request and token counts live in usage tables instead. - Data lineage
Unity Catalog tracks, without any set-up and at column granularity, where data comes from and where it goes across tables, notebooks, pipelines, jobs and dashboards. You can explore the graph in Catalog Explorer or query it through system tables.
- Usage tracking
Unity Gateway services log to
system.ai_gateway.usageand legacy endpoints tosystem.serving.endpoint_usage. Those system tables hold token figures and details about each call, never the payload itself.