refresh_continuous_aggregate()
Community
Refresh all buckets of a continuous aggregate in the refresh window given by window_start
and window_end
.
A continuous aggregate materializes aggregates in time buckets (e.g., min, max, average over 1 day worth of data), as determined by the time_bucket
interval specified when the continuous aggregate was created. Therefore, when refreshing the continuous aggregate, only buckets that completely fit within the refresh window will be refreshed. In other words, it is not possible to compute the aggregate over, for example, half a bucket. Therefore, any buckets that do no fit within the given refresh window will be excluded.
The function expects the window parameter values to have a time type that is compatible with the continuous aggregate’s time bucket expression—for example, if the time bucket is specified in TIMESTAMP WITH TIME ZONE
, then the start and end time should be a date or timestamp type. Note that a continuous aggregate using the TIMESTAMP WITH TIME ZONE
type aligns with the UTC time zone, so, if window_start
and window_end
is specified in the local time zone, any time zone shift relative UTC needs to be accounted for when refreshing in order to align with bucket boundaries.
Required Arguments
Name | Type | Description |
---|---|---|
continuous_aggregate | REGCLASS | The continuous aggregate to refresh. |
window_start | INTERVAL | Start of the window to refresh, has to be before window_end . NULL is eqivalent to MIN(timestamp) of the hypertable. |
window_end | INTERVAL | End of the window to refresh, has to be after window_start . NULL is eqivalent to MAX(timestamp) of the hypertable. |
Sample Usage
Refresh the continuous aggregate conditions
between 2020-01-01
and 2020-02-01
exclusive.
CALL refresh_continuous_aggregate('conditions', '2020-01-01', '2020-02-01');