timescaledb_information.compression_settings

This view exists for backwards compatibility. The supported views to retrieve information about compression are:

Deprecation

This section describes a feature that is deprecated on Timescale. We strongly recommend that you do not use this feature in a production environment. If you need more information, contact us.

Get information about compression-related settings for hypertables. Each row of the view provides information about individual orderby and segmentby columns used by compression.

How you use segmentby is the single most important thing for compression. It affects compresion rates, query performance, and what is compressed or decompressed by mutable compression.

Available columns

Name	Type	Description
`hypertable_schema`	TEXT	Schema name of the hypertable
`hypertable_name`	TEXT	Table name of the hypertable
`attname`	TEXT	Name of the column used in the compression settings
`segmentby_column_index`	SMALLINT	Position of attname in the compress_segmentby list
`orderby_column_index`	SMALLINT	Position of attname in the compress_orderby list
`orderby_asc`	BOOLEAN	True if this is used for order by ASC, False for order by DESC
`orderby_nullsfirst`	BOOLEAN	True if nulls are ordered first for this column, False if nulls are ordered last

Sample usage


CREATE TABLE hypertab (a_col integer, b_col integer, c_col integer, d_col integer, e_col integer);
SELECT table_name FROM create_hypertable('hypertab', by_range('a_col', 864000000));

ALTER TABLE hypertab SET (timescaledb.compress, timescaledb.compress_segmentby = 'a_col,b_col',
  timescaledb.compress_orderby = 'c_col desc, d_col asc nulls last');

SELECT * FROM timescaledb_information.compression_settings WHERE hypertable_name = 'hypertab';

-[ RECORD 1 ]----------+---------
hypertable_schema      | public
hypertable_name        | hypertab
attname                | a_col
segmentby_column_index | 1
orderby_column_index   |
orderby_asc            |
orderby_nullsfirst     |
-[ RECORD 2 ]----------+---------
hypertable_schema      | public
hypertable_name        | hypertab
attname                | b_col
segmentby_column_index | 2
orderby_column_index   |
orderby_asc            |
orderby_nullsfirst     |
-[ RECORD 3 ]----------+---------
hypertable_schema      | public
hypertable_name        | hypertab
attname                | c_col
segmentby_column_index |
orderby_column_index   | 1
orderby_asc            | f
orderby_nullsfirst     | t
-[ RECORD 4 ]----------+---------
hypertable_schema      | public
hypertable_name        | hypertab
attname                | d_col
segmentby_column_index |
orderby_column_index   | 2
orderby_asc            | t
orderby_nullsfirst     | f

Note

The by_range dimension builder is an addition to TimescaleDB 2.13.

timescaledb_information.compression_settings

Deprecation

Available columns

Sample usage

Note

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