add_reorder_policy()
CommunityCommunity functions are available under Timescale Community Edition. Click to learn more.Create a policy to reorder chunks on a given hypertable index in the background. (See reorder_chunk). Only one reorder policy may exist per hypertable. Only chunks that are the third from the most recent are reordered to avoid reordering chunks that are still being inserted into.
Tip
Once a chunk has been reordered by the background worker it is not reordered again. So if one were to insert significant amounts of data in to older chunks that have already been reordered, it might be necessary to manually re-run the reorderchunk function on older chunks, or to drop and re-create the policy if many older chunks have been affected.
| Name | Type | Description |
|---|---|---|
hypertable | REGCLASS | Hypertable to create the policy for. |
index_name | TEXT | Existing index by which to order rows on disk. |
initial_start | TIMESTAMPTZ | Time the policy is first run. Defaults to NULL. If omitted, then the schedule interval is the interval between the finish time of the last execution and the next start. If provided, it serves as the origin with respect to which the next_start is calculated |
timezone | TEXT | A valid time zone. If initial_start is also specified, subsequent executions of the reorder policy are aligned on its initial start. However, daylight savings time (DST) changes might shift this alignment. Set to a valid time zone if this is an issue you want to mitigate. If omitted, UTC bucketing is performed. Defaults to NULL. |
| Name | Type | Description |
|---|---|---|
if_not_exists | BOOLEAN | Set to true to avoid throwing an error if the reorder_policy already exists. A notice is issued instead. Defaults to false. |
| Column | Type | Description |
|---|---|---|
job_id | INTEGER | TimescaleDB background job id created to implement this policy |
SELECT add_reorder_policy('conditions', 'conditions_device_id_time_idx');
Creates a policy to reorder completed chunks by the existing (device_id, time) index. (See reorder_chunk).
Keywords
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