External Kuzu databases

Using the ATTACH statement, you can connect to an external Kuzu database. The external Kuzu database can be local or remote, for example, in an S3 bucket. Attaching to a local Kuzu database does not require installing any extensions. Attaching to a remote Kuzu database requires installing the httpfs extension. Aside from this requirement of installing the httpfs extension, attaching to a local vs. remote Kuzu database works the same way. Therefore, we only document how to attach to a remote Kuzu database here.

Usage

INSTALL httpfs;
LOAD httpfs;

Attach a remote Kuzu database

Use the ATTACH statement to attach to a remote Kuzu database:

ATTACH <DB_PATH> AS <alias> (dbtype kuzu)

• DB_PATH: Path to the (remote) database file (can either be an S3, GCS or HTTP URL)
• alias: Database alias to use. Aliases are mandatory for attaching to external Kuzu databases.

Unlike attaching to external RDBMSs, the alias is not used as a prefix of node and relationship tables. This is because at any point in time, you can attach to a single external Kuzu database (or be connected to the local Kuzu database you opened at the beginning of your session). Therefore, you don’t need to prefix your node and relationship tables. Instead, you will use the alias to DETACH from the external Kuzu database.

Suppose you are connected to a local database example.kuzu. After configuring a S3 connection, you can attach a Kuzu database hosted on S3 as:

ATTACH 's3://kuzu-example/university.kuzu.kuzu' AS uw (dbtype kuzu);

After attaching a remote Kuzu database, you no longer have access to the original local Kuzu database example.kuzu. After the ATTACH statement above, you can only query the external Kuzu database under s3://kuzu-example/university.kuzu.kuzu.

If you wish to attach to a database hosted on GCS instead, just replace the prefix s3:// with gs:// (in this case it would become gs://kuzu-example/university.kuzu). For more information on how to set up Kuzu with GCS, see here.

Execute queries on external Kuzu database

We only allow read-only queries to execute on external Kuzu databases (even if the external database is stored on local disk).

MATCH (p:Person)
RETURN p.name AS name, p.age AS age;

┌────────┬───────┐
│ name   │ age   │
│ STRING │ INT64 │
├────────┼───────┤
│ Alice  │ 30    │
│ Bob    │ 27    │
│ Carol  │ 19    │
│ Dan    │ 25    │
└────────┴───────┘

List attached databases

You can list all the databases you have attached to by running the following command:

CALL SHOW_ATTACHED_DATABASES() RETURN *;

Detach from a remote Kuzu database

To detach from an external Kuzu database, use DETACH [ALIAS]:

DETACH uw;

After the DETACH statement, you can continue querying your local Kuzu database example.kuzu. Therefore, detaching from an external Kuzu database switches your Kuzu database back to the local database you had started your session with.

Use a local cache for remote files

When connecting to a remote external Kuzu database, say the s3://kuzu-example/university.kuzu database in our example above, you would use the httpfs extension. When querying this remote database in Cypher, Kuzu will make HTTPS calls to the remote server to query this database. You can speed up your Cypher queries by using the local httpfs cache, similar to how you can speed up LOAD FROM queries using the local httpfs cache for scanning remote files. You can enable the local cache by running CALL HTTP_CACHE_FILE=TRUE; after installing the httpfs extension and before attaching to the remote Kuzu database.