Configuration¶

Create a catalog properties file (e.g., etc/catalog/lance.properties) to configure the Lance connector.

Configuration Properties¶

Property	Description	Default
`connector.name`	Must be set to `lance`	-
`lance.impl`	Namespace implementation: `dir`, `rest`, `glue`, `hive2`, `hive3`, or full class name	`dir`

Any other lance.* properties are stripped of the lance. prefix and passed to the namespace implementation.

Namespace Levels¶

Lance namespaces support different access modes depending on the underlying namespace structure. These settings apply to all namespace implementations.

Default Mode¶

Direct schema-to-namespace mapping. Schemas map directly to namespaces in the catalog.

connector.name=lance
lance.impl=dir
lance.root=s3://my-bucket/lance-warehouse

CREATE SCHEMA lance.myschema;
CREATE TABLE lance.myschema.users (id BIGINT, name VARCHAR);

Single Level Mode¶

Uses a virtual default schema. All tables are stored at the root level. CREATE SCHEMA is not supported.

connector.name=lance
lance.impl=dir
lance.root=s3://my-bucket/lance-warehouse
lance.single_level_ns=true

-- Only the "default" schema is available
CREATE TABLE lance.default.users (id BIGINT, name VARCHAR);

Parent Prefix Mode¶

For namespaces with deeper hierarchies (3+ levels). The parent prefix is prepended to all namespace operations.

connector.name=lance
lance.impl=dir
lance.root=s3://my-bucket/lance-warehouse
lance.parent=org$team

-- Schema "myschema" maps to namespace ["org", "team", "myschema"]
CREATE SCHEMA lance.myschema;
CREATE TABLE lance.myschema.users (id BIGINT, name VARCHAR);

Property	Description	Default
`lance.single_level_ns`	Enable single-level mode with virtual `default` schema	`false`
`lance.parent`	Parent namespace prefix (levels separated by `$`)	-

Read and Write Settings¶

Control batch sizes for vectorized operations:

Property	Description	Default
`lance.read_batch_size`	Rows per batch during vectorized reads	`8192`
`lance.write_batch_size`	Rows to batch before writing to Arrow	`10000`
`lance.max_rows_per_file`	Maximum rows per Lance file	`1000000`
`lance.max_rows_per_group`	Maximum rows per row group	`100000`

Examples¶

Directory Namespace¶

The directory namespace allows operating against Lance datasets from any storage.

connector.name=lance
lance.impl=dir
lance.root=s3://my-bucket/lance-warehouse
lance.storage.region=us-east-1
lance.storage.access_key_id=YOUR_ACCESS_KEY
lance.storage.secret_access_key=YOUR_SECRET_KEY

REST Namespace¶

The REST namespace connects to a Lance REST catalog server.

connector.name=lance
lance.impl=rest
lance.uri=http://localhost:8080
lance.header.Authorization=Bearer your-token