---
title: "Catalog schema"
slug: "dev-catalog-reference-schema"
updated: 2026-10-30T18:18:51Z
published: 2026-10-30T18:18:51Z
canonical: "docs.vastdata.com/dev-catalog-reference-schema"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vastdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Catalog schema

*Applies to VAST Cluster 5.5.*

The columns of the VAST Catalog table, `vast_big_catalog_table`, in VAST Cluster 5.5. Types are the Arrow types the Python SDK returns; the SQL types in Trino and Spark follow the usual [type mapping](/develop/docs/dev-database-reference-data-types). To see your own Catalog's columns, including any user-defined ones, run `tx.catalog().columns()` (see the [quickstart](/develop/docs/dev-catalog-quickstart#open-the-catalog)).

## Columns

These are the 33 columns `tx.catalog().columns()` returns on VAST Cluster 5.5, before any user-defined columns. See also [VAST Catalog Overview](/docs-5-5/docs/vast-catalog-overview) and [vastcatalogconfig columns](/docs-5-5/docs/vastcatalogconfig-columns).

| Column | Type | Description |
| --- | --- | --- |
| `name` | `string` | Element name |
| `extension` | `string` | File extension |
| `parent_path` | `string` | Path of the directory the element is in |
| `search_path` | `string` | Virtual column: filter on it to restrict a query to a subtree. See [search_path](/develop/docs/dev-catalog-concepts-index#searchpath). |
| `symlink_path` | `string` | For a symbolic link: the target it points to, as stored in the link |
| `element_type` | `string` | Type of element: `FILE` (a file or S3 object), `DIR` (a directory), `SYMLINK` (a symbolic link), `SCHEMA` or `TABLE` (a VAST DataBase schema or table) |
| `size` | `int64` | The size of the element. For a symbolic link, the length of its target |
| `used` | `int64` | Number of bytes used on disk |
| `nlinks` | `int64` | Number of hard links to the element. A file with two hard links is two rows, one per name, each with `nlinks` 2 |
| `creation_time` | `timestamp[ns]` | When the element was created |
| `mtime` | `timestamp[ns]` | Time of last modification |
| `atime` | `timestamp[ns]` | Time of last access |
| `ctime` | `timestamp[ns]` | Time of last file-system metadata change |
| `uid` | `int32` | Owner's POSIX UID |
| `owner_name` | `string` | Owner's user name |
| `owner_sid` | `string` | Owner's SMB SID |
| `login_name` | `string` | The login name of the element's owner |
| `gid` | `int32` | Owner group's POSIX GID |
| `group_owner_name` | `string` | Owner group's name |
| `group_owner_sid` | `string` | Owner group's SMB SID |
| `nfs_mode_bits` | `int32` | POSIX permission mode bits |
| `name_aces_exist` | `bool` | Whether extended ACEs (NTFS, NFSv4 or POSIX) exist on the element |
| `major_device` | `int32` | Major device number |
| `minor_device` | `int32` | Minor device number |
| `s3_locks_legal_hold` | `bool` | Whether the object has an S3 Object Lock legal hold |
| `s3_locks_retention` | `struct<mode: int8, timeout: time64[us]>` | S3 Object Lock retention |
| `user_tags` | `map<string, string>` | The element's S3 tags. Null for an element without tags. |
| `user_tags_count` | `int16` | How many S3 tags the element has |
| `user_metadata` | `map<string, string>` | The object's S3 user metadata. Keys are stored without the `x-amz-meta-` prefix. |
| `abac_tags` | `list<string>` | ABAC tags on the element |
| `nfs4_xattrs` | `map<string, string>` | NFSv4.2 extended attributes on the element |
| `phandle` | `struct<clone_id: int32, handle_id: int64>` | The cluster's internal identifier for the element |
| `tenant_id` | `int32` | Tenant information. On a cluster with only the default tenant, every row had `-1` |

## User-defined columns

Your platform team can add a column for an S3 tag key, an S3 metadata key or an NFSv4.2 extended attribute ([Configuring VAST Catalog](/docs-5-5/docs/configuring-vast-catalog), "User defined attributes"). The column is filled in from the next snapshot on.

| Attribute type | Column | Holds |
| --- | --- | --- |
| Tag | `tag_<key>` | The value of the S3 tag `<key>` |
| Metadata | `metadata_<key>` | The value of the S3 user metadata `x-amz-meta-<key>` |
| NFSv4 xattr | `nfs4_xattr_<key>` | The value of the NFSv4.2 extended attribute `<key>` |

User-defined columns are `string`, appear in `columns()` from the next snapshot after they're added, and filters on them push down to the cluster.

Tags stay in `user_tags` as well. See [tags and metadata](/develop/docs/dev-catalog-guides-tags-and-metadata).

## Table names

|  | Database (bucket) | Schema | Table |
| --- | --- | --- | --- |
| Catalog | `vast-big-catalog-bucket` | `vast_big_catalog_schema` | `vast_big_catalog_table` |

For the names in Trino and Spark, see [Trino and Spark](/develop/docs/dev-catalog-integrations-trino-and-spark#table-names).

## See also

- [Concepts: what a row is](/develop/docs/dev-catalog-concepts-index#what-a-row-is).
- [Audit log schema](/develop/docs/dev-catalog-reference-audit-log-schema).