TimescaleDB API Reference - ALTER TABLE (Compression) Community - 《TimescaleDB v2.1 Documentation》

ALTER TABLE (Compression) Community

ALTER TABLE (Compression) Community

‘ALTER TABLE’ statement is used to turn on compression and set compression options.

The syntax is:

ALTER TABLE <table_name> SET (timescaledb.compress, timescaledb.compress_orderby = '<column_name> [ASC | DESC] [ NULLS { FIRST | LAST } ] [, ...]',
timescaledb.compress_segmentby = '<column_name> [, ...]'
);

Required Options

Name	Description
`timescaledb.compress`	Boolean to enable compression

Other Options

Name	Description
`timescaledb.compress_orderby`	Order used by compression, specified in the same way as the ORDER BY clause in a SELECT query. The default is the descending order of the hypertable’s time column.
`timescaledb.compress_segmentby`	Column list on which to key the compressed segments. An identifier representing the source of the data such as `device_id` or `tags_id` is usually a good candidate. The default is no `segment by` columns.

Parameters

Name	Description
`table_name`	Name of the hypertable that will support compression
`column_name`	Name of the column used to order by and/or segment by

Sample Usage

Configure a hypertable that ingests device data to use compression.

ALTER TABLE metrics SET (timescaledb.compress, timescaledb.compress_orderby = 'time DESC', timescaledb.compress_segmentby = 'device_id');