Manually refresh a continuous aggregate

If you need to manually refresh a continuous aggregate, you can use the refresh command. This recomputes the data within the window that has changed in the underlying hypertable since the last refresh. Therefore, if only a few buckets need updating, the refresh runs quickly.

If you have recently dropped data from a hypertable with a continuous aggregate, calling refresh_continuous_aggregate on a region containing dropped chunks recalculates the aggregate without the dropped data. See [drop data][cagg-drop-data] for more information.

The refresh command takes three arguments:

• The name of the continuous aggregate view to refresh
• The timestamp of the beginning of the refresh window
• The timestamp of the end of the refresh window

Only buckets that are wholly within the specified range are refreshed. For example, if you specify 2021-05-01', '2021-06-01 the only buckets that are refreshed are those up to but not including 2021-06-01. It is possible to specify NULL in a manual refresh to get an open-ended range, but we do not recommend using it, because you could inadvertently materialize a large amount of data, slow down your performance, and have unintended consequences on other policies like data retention.

To manually refresh a continuous aggregate, use the refresh command:

Follow the logic used by automated refresh policies and avoid refreshing time buckets that are likely to have a lot of writes. This means that you should generally not refresh the latest incomplete time bucket. To include the latest raw data in your queries, use [real-time aggregation][real-time-aggregates] instead.

===== PAGE: https://docs.tigerdata.com/use-timescale/continuous-aggregates/drop-data/ =====

Examples:

Example 1 (sql):

SELECT add_continuous_aggregate_policy('conditions_summary_hourly',
      start_offset => NULL,
      end_offset => INTERVAL '1 h',
      schedule_interval => INTERVAL '1 h');

Example 2 (sql):

SELECT add_continuous_aggregate_policy('conditions_summary_hourly',
      start_offset => INTERVAL '1 month',
      end_offset => INTERVAL '1 h',
      schedule_interval => INTERVAL '1 h');

Example 3 (sql):

SELECT add_continuous_aggregate_policy('conditions_summary_daily',
      start_offset => INTERVAL '1 day',
      end_offset => INTERVAL '1 h',
      schedule_interval => INTERVAL '1 h');

Example 4 (sql):

SELECT add_continuous_aggregate_policy('conditions_summary_daily',
      start_offset => NULL
      end_offset => INTERVAL '1 day',
      schedule_interval => INTERVAL '1 hour');