set_chunk_time_interval()

Change the chunk time interval of a hypertable

Since 0.1.0

Sets the chunk_time_interval on a . The new interval is used when new s are created, and time intervals on existing s are not changed.

Samples

For a TIMESTAMP column, set chunk_time_interval to 24 hours:

SELECT set_chunk_time_interval('conditions', INTERVAL '24 hours');
SELECT set_chunk_time_interval('conditions', 86400000000);

For a time column expressed as the number of milliseconds since the UNIX epoch, set chunk_time_interval to 24 hours:

SELECT set_chunk_time_interval('conditions', 86400000);

Arguments

The syntax is:

SELECT set_chunk_time_interval(
    hypertable = '<hypertable_name>',
    chunk_time_interval = <interval>,
    dimension_name = '<dimension_name>'
);

Name	Type	Default	Required	Description
hypertable	REGCLASS	-	✔	or to update interval for.
chunk_time_interval	See note	-	✔	Event time that each new covers.
dimension_name	NAME	NULL	✖	The name of the time dimension to set the number of partitions for. Only use dimension_name when your has multiple time dimensions.

If you change time interval you may see a that is smaller than the new interval. For example, if you have two 7-day s that cover 14 days, then change chunk_time_interval to 3 days, you may end up with a transition covering one day. This happens because the start and end of the new is calculated based on dividing the timeline by the chunk_time_interval starting at epoch 0. This leads to the following s [0, 3), [3, 6), [6, 9), [9, 12), [12, 15), [15, 18) and so on. The two 7-day s covered data up to day 14: [0, 7), [8, 14), so the 3-day for [12, 15) is reduced to a one day . The following [15, 18) is created as a full 3 day .

The valid types for the chunk_time_interval depend on the type used for the time column:

time column type	chunk_time_interval type	Time unit
TIMESTAMP	INTERVAL	days, hours, minutes, etc
	INTEGER or BIGINT	microseconds
TIMESTAMPTZ	INTERVAL	days, hours, minutes, etc
	INTEGER or BIGINT	microseconds
DATE	INTERVAL	days, hours, minutes, etc
	INTEGER or BIGINT	microseconds
SMALLINT	SMALLINT	The same time unit as the time column
INT	INT	The same time unit as the time column
BIGINT	BIGINT	The same time unit as the time column

For more information, see partitioning.

Returns

This function returns void.