# System Tables

System tables are read-only relations in the `deltastream.sys` virtual schema that expose metadata about your DeltaStream organization. They can be queried using standard SQL `SELECT` statements, which makes them useful for programmatic access, automation, and agents that need to inspect or reason about the state of your DeltaStream resources.

## Syntax

```sql
SELECT column [, ...]
FROM deltastream.sys."<table_name>"
[ WHERE condition ]
[ ORDER BY column ]
[ LIMIT n ];
```

## Description

System tables provide the same information as the corresponding `LIST` and `DESCRIBE` commands, but as queryable SQL relations. This allows you to filter, sort, join, and aggregate metadata in ways that the dedicated commands do not support.

{% hint style="info" %}
**Note** System table names must be quoted with double quotes, e.g. `deltastream.sys."compute_pools"`.
{% endhint %}

### Access Control

Each system table enforces [role-based access control](/overview/core-concepts/access-control.md) automatically. Rows are filtered to only those resources the current role has `USAGE` privileges on. No additional `WHERE` clause is needed to scope results to the current role.

### Column Types

Columns in system tables use the following DeltaStream types:

| PostgreSQL type           | DeltaStream type |
| ------------------------- | ---------------- |
| `boolean`                 | `BOOLEAN`        |
| `smallint`                | `SMALLINT`       |
| `integer`                 | `INTEGER`        |
| `bigint`                  | `BIGINT`         |
| `varchar`, `text`, `uuid` | `VARCHAR`        |
| `timestamptz`             | `TIMESTAMP_LTZ`  |

## Available System Tables

| Table                                                                                         | Description                                                     |
| --------------------------------------------------------------------------------------------- | --------------------------------------------------------------- |
| [`audit_logs`](/reference/sql-syntax/systables/audit-logs.md)                                 | Audit log of all actions performed in the organization          |
| [`compute_pools`](/reference/sql-syntax/systables/compute-pools.md)                           | Compute pools defined in the organization                       |
| [`databases`](/reference/sql-syntax/systables/databases.md)                                   | Databases in the organization                                   |
| [`descriptor_sources`](/reference/sql-syntax/systables/descriptor-sources.md)                 | Protobuf descriptor sources                                     |
| [`function_sources`](/reference/sql-syntax/systables/function-sources.md)                     | Function source packages (JARs)                                 |
| [`functions`](/reference/sql-syntax/systables/functions.md)                                   | User-defined functions (UDFs)                                   |
| [`organization_defaults`](/reference/sql-syntax/systables/organization-defaults.md)           | Per-user session defaults (role, database, store, compute pool) |
| [`organization_subscriptions`](/reference/sql-syntax/systables/organization-subscriptions.md) | Subscription plan details for the organization                  |
| [`organizations`](/reference/sql-syntax/systables/organizations.md)                           | Organizations the current user is a member of                   |
| [`pgusers`](/reference/sql-syntax/systables/pgusers.md)                                       | PostgreSQL-compatible user credentials                          |
| [`queries`](/reference/sql-syntax/systables/queries.md)                                       | Streaming queries (active and historical)                       |
| [`query_tags`](/reference/sql-syntax/systables/query-tags.md)                                 | Key/value tags attached to queries                              |
| [`relation_columns`](/reference/sql-syntax/systables/relation-columns.md)                     | Column definitions for all relations                            |
| [`relations`](/reference/sql-syntax/systables/relations.md)                                   | Streams, changelogs, tables, materialized views, and indexes    |
| [`role_privileges`](/reference/sql-syntax/systables/role-privileges.md)                       | Privilege grants for roles                                      |
| [`roles`](/reference/sql-syntax/systables/roles.md)                                           | Roles defined in the organization                               |
| [`schema_registries`](/reference/sql-syntax/systables/schema-registries.md)                   | Schema registry connections                                     |
| [`schemas`](/reference/sql-syntax/systables/schemas.md)                                       | Schemas (namespaces) within databases                           |
| [`secrets`](/reference/sql-syntax/systables/secrets.md)                                       | Secrets (metadata only, values never exposed)                   |
| [`stores`](/reference/sql-syntax/systables/stores.md)                                         | External system connections                                     |
| [`user_grants`](/reference/sql-syntax/systables/user-grants.md)                               | User-to-role membership grants                                  |
| [`userdatas`](/reference/sql-syntax/systables/userdatas.md)                                   | Per-user key/value metadata (internal UI state)                 |


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