SHOW INDEXES¶

List all indexes defined on a Lance table.

Spark Extension Required

This feature requires the Lance Spark SQL extension to be enabled. See Spark SQL Extensions for configuration details.

Overview¶

The SHOW INDEXES command returns one row for each index on a Lance table. The information is retrieved using the Dataset.describeIndices method, and the output columns align with the attributes of org.lance.index.IndexDescription, excluding the per-segment metadata list.

This command is useful for inspecting existing indexes, verifying index creation, and understanding the high-level properties of each index.

Syntax¶

SQL

SHOW INDEXES FROM multipartIdentifier;
SHOW INDEXES IN multipartIdentifier;
SHOW INDEX FROM multipartIdentifier;
SHOW INDEX IN multipartIdentifier;

multipartIdentifier can be a fully qualified table name (for example lance.db.users) or a shorter form depending on the current catalog and namespace configuration.

Examples¶

List indexes on a table¶

List all indexes on a Lance table lance.db.users:

SQL

SHOW INDEXES FROM lance.db.users;

You can also use the IN keyword or the singular INDEX spelling:

SQL

SHOW INDEX IN lance.db.users;

Output¶

The SHOW INDEXES command returns the following columns:

Column	Type	Description
`name`	string	Logical name of the index.
`fields`	array	List of column names included in the index.
`index_type`	string	Human-readable index type (for example `btree`).
`num_indexed_fragments`	long	Number of fragments fully or partially covered by the index.
`num_indexed_rows`	long	Approximate number of rows covered by the index.
`num_unindexed_fragments`	long	Number of fragments that are not yet indexed.
`num_unindexed_rows`	long	Approximate number of rows that are not yet covered by the index.

Notes¶

The fields column returns the logical column names from the Lance schema, ordered according to the index definition.