DuckLake has been released in May 2025. Read the announcement blog post.

The ducklake extension add support for attaching to databases stored in the DuckLake format:

Installing and Loading

To install ducklake, run:

INSTALL ducklake;

The ducklake extension will be transparently autoloaded on first use in an ATTACH clause. If you would like to load it manually, run:

LOAD ducklake;

Usage

ATTACH 'ducklake:metadata.ducklake' AS my_ducklake (DATA_PATH 'data_files');
USE my_ducklake;

Tables

In DuckDB, the ducklake extension stores the catalog tables for a DuckLake named my_ducklake in the __ducklake_metadata_my_ducklake catalog.

Functions

Note that DuckLake registers several functions. These should be called with the catalog name as the first argument, e.g.:

FROM ducklake_snapshots('my_ducklake');

┌─────────────┬────────────────────────────┬────────────────┬──────────────────────────┐
│ snapshot_id │       snapshot_time        │ schema_version │         changes          │
│    int64    │  timestamp with time zone  │     int64      │ map(varchar, varchar[])  │
├─────────────┼────────────────────────────┼────────────────┼──────────────────────────┤
│      0      │ 2025-05-26 11:41:10.838+02 │       0        │ {schemas_created=[main]} │
└─────────────┴────────────────────────────┴────────────────┴──────────────────────────┘

ducklake_snapshots

Returns the snapshots stored in the DuckLake catalog name catalog.

The information is encoded into a table with the following schema:

ducklake_table_info

The ducklake_table_info function returns information on the tables stored in the DuckLake catalog named catalog.

The information is encoded into a table with the following schema:

ducklake_table_insertions

The ducklake_table_insertions function returns the rows inserted in a given table between snapshots of given versions or timestamps. The function has two variants, depending on whether start_snapshot and end_snapshot have types BIGINT or TIMESTAMP WITH TIME ZONE.

The schema of the table returned by the function is equivalent to that of the table table_name.

ducklake_table_deletions

The ducklake_table_deletions function returns the rows deleted from a given table between snapshots of given versions or timestamps. The function has two variants, depending on whether start_snapshot and end_snapshot have types BIGINT or TIMESTAMP WITH TIME ZONE.

The schema of the table returned by the function is equivalent to that of the table table_name.

ducklake_table_changes

The ducklake_table_changes function returns the rows changed in a given table between snapshots of given versions or timestamps. The function has two variants, depending on whether start_snapshot and end_snapshot have types BIGINT or TIMESTAMP WITH TIME ZONE.

The schema of the table returned by the function contains the following three columns plus the schema of the table table_name.

Commands

ducklake_cleanup_old_files

The ducklake_cleanup_old_files function cleans up old files in the DuckLake denoted by catalog. Upon success, it returns a table with a single column (Success) and 0 rows.

ducklake_expire_snapshots

The ducklake_expire_snapshots function expires snapshots with the versions specified by the versions parameter or the ones older than the older_than parameter. Upon success, it returns a table with a single column (Success) and 0 rows.

ducklake_merge_adjacent_files

The ducklake_merge_adjacent_files function merges adjacent files in the storage. Upon success, it returns a table with a single column (Success) and 0 rows.