ALTER TABLE ALTER COLUMN SET/DROP PARQUET

Sets or removes per-column Parquet encoding and compression configuration on existing tables. These settings only affect Parquet partitions and are ignored for native partitions.

SET

Override the default Parquet encoding, compression, or both for a column. The syntax is SET PARQUET(encoding [, compression[(level)]]). Use default for the encoding when specifying compression only.

Set encoding only

ALTER TABLE sensors ALTER COLUMN temperature SET PARQUET(rle_dictionary);

Set compression only (with optional level)

ALTER TABLE sensors ALTER COLUMN temperature SET PARQUET(default, zstd(3));

Set both encoding and compression

ALTER TABLE sensors ALTER COLUMN temperature SET PARQUET(rle_dictionary, zstd(3));

DROP

Reset per-column overrides back to the server defaults.

Reset to defaults

ALTER TABLE sensors ALTER COLUMN temperature DROP PARQUET;

Supported encodings and codecs

See the CREATE TABLE reference for the full list of supported encodings, compression codecs, and their valid column types.