---
title: System indexes
description: The PingDirectory server contains a set of system database index files that ensure that the server operates efficiently. These indexes cannot be modified or deleted.
component: pingdirectory
version: 11.0
page_id: pingdirectory:pingdirectory_server_administration_guide:pd_ds_system_indexes
canonical_url: https://docs.pingidentity.com/pingdirectory/11.0/pingdirectory_server_administration_guide/pd_ds_system_indexes.html
revdate: September 13, 2023
page_aliases: ["pd_ds_viewing_system_indexes.adoc"]
section_ids:
  viewing-the-system-indexes: Viewing the system indexes
  steps: Steps
  example: Example:
---

# System indexes

The PingDirectory server contains a set of system database index files that ensure that the server operates efficiently. These indexes cannot be modified or deleted.

**System Indexes**

| Index       | Description                                                                                                                                                                                                                           |
| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| dn2id       | Allows quick retrieval of distinguished names (DNs). The `dn2id` database has one record for each entry. The key is the normalized entry DN and the value is the entry ID.                                                            |
| id2entry    | Allows quick retrieval of entries. The `id2entry` database contains the LDAP entries. The database key is the entry ID and the value is the entry contents.                                                                           |
| referral    | Allows quick retrieval of referrals. The referral database called `dn2uri` contains URIs from referral entries. The key is the DN of the referral entry and the value is that of a labeled URI in the `ref` attribute for that entry. |
| id2children | Allows quick retrieval of an entry and its children. The `id2children` database provides a mapping between an entry's unique identifier and the entry unique identifiers of the corresponding entry's children.                       |
| id2subtree  | Allows quick retrieval of an entry's subtree. The `id2subtree` database provides a mapping between an entry's unique identifier and the unique identifiers in its subtree.                                                            |

## Viewing the system indexes

### Steps

* To view the system and user indexes, use the `dbtest` command.

  #### Example:

  ```shell
  $ bin/dbtest list-index-status --baseDN dc=example,dc=com --backendID userRoot
  ```

  The index status indicates whether or not an index is trusted. An untrusted index requires rebuilding.