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billy-the-fish merged 5 commits into from
Sep 12, 2025
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chore: add note about chunks. #4420

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825d147
chore: add note about chunks.
billy-the-fish Sep 12, 2025
4c1797d
chore: update on review.
billy-the-fish Sep 12, 2025
df08f24
Merge branch 'latest' into 4419-docs-rfcadd-a-note-about-chunk-intervals
billy-the-fish Sep 12, 2025
4bd4f8d
Update api/hypertable/set_chunk_time_interval.md
billy-the-fish Sep 12, 2025
4a5eb45
chore: update on review.
billy-the-fish Sep 12, 2025
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30 changes: 15 additions & 15 deletions api/hypertable/set_chunk_time_interval.md
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Expand Up @@ -32,12 +32,22 @@ UNIX epoch, set `chunk_time_interval` to 24 hours:
SELECT set_chunk_time_interval('conditions', 86400000);
```

## Required arguments
## Arguments

|Name|Type|Description|
|-|-|-|
|`hypertable`|REGCLASS|Hypertable or continuous aggregate to update interval for|
|`chunk_time_interval`|See note|Event time that each new chunk covers|

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

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

The valid types for the `chunk_time_interval` depend on the type used for the
hypertable `time` column:
Expand All @@ -56,15 +66,5 @@ hypertable `time` column:

For more information, see [hypertable partitioning][hypertable-partitioning].

## Optional arguments

|TEXT|Description|
|-|-|-|
|`dimension_name`|REGCLASS|The name of the time dimension to set the number of partitions for|

You need to use `dimension_name` argument only if your hypertable has multiple
time dimensions.



[hypertable-partitioning]: /use-timescale/:currentVersion:/hypertables/#hypertable-partitioning