# Inspect service metadata with system tables

Use Coordinator DB's documented `system` relations to inspect active requests, query history, table definitions and effective settings. A cloud-provider role does not add SQL commands. There is no general `SYSTEM` command interface for maintenance actions.

```sql
SELECT name, value
FROM system.settings
WHERE name IN ('max_execution_time', 'max_memory_usage')
FORMAT csv;
```

## Choose the right relation

`system.processes` describes active requests. `system.query_log` describes recorded request events, including terminal failures. `system.tables` and `system.columns` describe SQL objects. Always use the `system` qualifier and inspect the reference for the available columns instead of copying a metadata query for another product.

Most observational metadata is read-only. A relation's existence does not mean its counters can be edited. Use ordinary CREATE, ALTER and DROP statements for object changes, and the documented settings interface for configuration.

## Diagnose permissions and connection context

Confirm authentication, the selected database and the exact error before assuming a hosting restriction. Server-only XML options do not appear in `system.settings`; they are applied at startup. A missing column often means the query assumes an unsupported metadata contract.

See [system tables](https://coordinatordb.com/docs/reference/system-tables/overview), [settings](https://coordinatordb.com/docs/reference/settings) and [SQL statements](https://coordinatordb.com/docs/reference/statements).