DESCRIBE TABLE¶

Inspect table structure and metadata.

Describe table structure:

DESCRIBE TABLE users;

Show detailed table information:

DESCRIBE EXTENDED users;

Spark displays fixed-size vectors as array<float> or array<double>. Use DESCRIBE EXTENDED or SHOW TBLPROPERTIES to inspect their dimensions, including after reloading the table:

CREATE TABLE vectors (id BIGINT, embedding ARRAY<FLOAT>)
USING lance
TBLPROPERTIES ('embedding.arrow.fixed-size-list.size' = '756');

-- Reload the table so dimensions are read from the stored Lance schema.
REFRESH TABLE vectors;

DESCRIBE EXTENDED vectors;
-- Table Properties includes: embedding.arrow.fixed-size-list.size=756

SHOW TBLPROPERTIES vectors ('embedding.arrow.fixed-size-list.size');
-- value: 756

Vector dimensions come from the Lance schema and take precedence over table config. Removing a config entry with UNSET TBLPROPERTIES leaves the vector size and the dimension reported by DESCRIBE EXTENDED and SHOW TBLPROPERTIES unchanged.