timescaledb_information.chunks

Since 0.1.0

Get metadata about the chunks of hypertables.

This view shows metadata for the chunk‘s primary time-based dimension. For information about a hypertable‘s secondary dimensions, the dimensions view should be used instead.

If the chunk‘s primary dimension is of a time datatype, range_start and range_end are set. Otherwise, if the primary dimension type is integer based, range_start_integer and range_end_integer are set.

Samples

Get information about the chunks of a hypertable.

Dimension builder by_range was introduced in TimescaleDB 2.13. The chunk_creation_time metadata was introduced in TimescaleDB 2.13.

CREATE TABLESPACE tablespace1 location '/usr/local/pgsql/data1';

CREATE TABLE hyper_int (a_col integer, b_col integer, c integer);
SELECT create_hypertable('hyper_int', by_range('a_col', 10));
CREATE OR REPLACE FUNCTION integer_now_hyper_int() returns int LANGUAGE SQL STABLE as $$ SELECT coalesce(max(a_col), 0) FROM hyper_int $$;
SELECT set_integer_now_func('hyper_int', 'integer_now_hyper_int');

INSERT INTO hyper_int SELECT generate_series(1,5,1), 10, 50;

SELECT attach_tablespace('tablespace1', 'hyper_int');
INSERT INTO hyper_int VALUES( 25 , 14 , 20), ( 25, 15, 20), (25, 16, 20);

SELECT * FROM timescaledb_information.chunks WHERE hypertable_name = 'hyper_int';

-[ RECORD 1 ]----------+----------------------
hypertable_schema      | public
hypertable_name        | hyper_int
chunk_schema           | _timescaledb_internal
chunk_name             | _hyper_7_10_chunk
primary_dimension      | a_col
primary_dimension_type | integer
range_start            |
range_end              |
range_start_integer    | 0
range_end_integer      | 10
is_compressed          | f
chunk_tablespace       |
-[ RECORD 2 ]----------+----------------------
hypertable_schema      | public
hypertable_name        | hyper_int
chunk_schema           | _timescaledb_internal
chunk_name             | _hyper_7_11_chunk
primary_dimension      | a_col
primary_dimension_type | integer
range_start            |
range_end              |
range_start_integer    | 20
range_end_integer      | 30
is_compressed          | f
chunk_tablespace       | tablespace1

Returns

Name	Type	Description
hypertable_schema	TEXT	Schema name of the hypertable
hypertable_name	TEXT	Table name of the hypertable
chunk_schema	TEXT	Schema name of the chunk
chunk_name	TEXT	Name of the chunk
primary_dimension	TEXT	Name of the column that is the primary dimension
primary_dimension_type	REGTYPE	Type of the column that is the primary dimension
range_start	TIMESTAMP WITH TIME ZONE	Start of the range for the chunk‘s dimension
range_end	TIMESTAMP WITH TIME ZONE	End of the range for the chunk‘s dimension
range_start_integer	BIGINT	Start of the range for the chunk‘s dimension, if the dimension type is integer based
range_end_integer	BIGINT	End of the range for the chunk‘s dimension, if the dimension type is integer based
is_compressed	BOOLEAN	Is the chunk in the columnstore?
chunk_tablespace	TEXT	Tablespace used by the chunk
chunk_creation_time	TIMESTAMP WITH TIME ZONE	The time when this chunk was created for data addition