Manage automated and manual tiering

You use tiered storage to save on storage costs. Specifically, you can migrate rarely used data from Timescale's standard high-performance storage to the object storage. After you enable tiered storage, you then either create automated tiering policies or manually tier and untier data.

You can query the data on the object storage tier, but you cannot modify it. Make sure that you are not tiering data that needs to be actively modified.

Enable tiered storage

You enable tiered storage from the Overview tab in Console.

In Timescale Console, select the service to modify.
You see the Overview section.
Scroll down, then click Enable tiered storage.
When tiered storage is enabled, you see the amount of data in the tiered object storage.
Note
Data tiering is available in Scale and Enterprise pricing plans only.

Automate tiering with policies

A tiering policy automatically moves any chunks that only contain data older than the move_after threshold to the object storage tier. This works similarly to a data retention policy, but chunks are moved rather than deleted.

A tiering policy schedules a job that runs periodically to asynchronously migrate eligible chunks to object storage. Chunks are considered tiered once they appear in the timescaledb_osm.tiered_chunks view.

You can add tiering policies to hypertables, including continuous aggregates. To manage tiering policies, connect to your service and run the queries below in the data mode, the SQL editor, or using psql.

Add a tiering policy

To add a tiering policy, call add_tiering_policy:


SELECT add_tiering_policy(hypertable REGCLASS, move_after INTERVAL, if_not_exists BOOL = false);

For example, to tier chunks that are more than three days old in the example hypertable:


SELECT add_tiering_policy('example', INTERVAL '3 days');

By default, a tiering policy runs hourly on your database. To change this interval, call alter_job.

Remove a tiering policy

To remove an existing tiering policy, call remove_tiering_policy:


SELECT remove_tiering_policy(hypertable REGCLASS, if_exists BOOL = false);

For example, to remove the tiering policy from the example hypertable:


SELECT remove_tiering_policy('example');

If you remove a tiering policy, the remaining scheduled chunks are not tiered. However, chunks in tiered storage are not untiered. You untier chunks manually to local storage.

Manually tier and untier chunks

If tiering policies do not meet your current needs, you can tier and untier chunks manually. To do so, connect to your service and run the queries below in the data mode, the SQL editor, or using psql.

Tier chunks

Tiering a chunk is an asynchronous process that schedules the chunk to be tiered. In the following example, you tier chunks older than three days in the example hypertable. You then list the tiered chunks.

Select all chunks in example that are older than three days:


SELECT show_chunks('example', older_than => INTERVAL '3 days');

This returns a list of chunks. Take a note of the chunk names:


|1|_timescaledb_internal_hyper_1_2_chunk|
|2|_timescaledb_internal_hyper_1_3_chunk|

Call tier_chunk to manually tier each chunk:


SELECT tier_chunk( '_timescaledb_internal_hyper_1_2_chunk');

Repeat for all chunks you want to tier.
Tiering a chunk schedules it for migration to the object storage tier, but the migration won't happen immediately. Chunks are tiered one at a time in order to minimize database resource consumption. A chunk is marked as migrated and deleted from the standard storage only after it has been durably stored in the object storage tier. You can continue to query a chunk during migration.
To see which chunks are tiered into the object storage tier, use the tiered_chunks informational view:
```
SELECT * FROM timescaledb_osm.tiered_chunks;
```

To see which chunks are scheduled for tiering either by policy or by a manual call, but have not yet been tiered, use this view:


SELECT * FROM timescaledb_osm.chunks_queued_for_tiering ;

Untier chunks

To update data in a tiered chunk, move it back to the standard high-performance storage tier in Timescale Cloud. Untiering chunks is a synchronous process. Chunks are renamed when the data is untiered.

To untier a chunk, call the untier_chunk stored procedure.

Check which chunks are currently tiered:


SELECT * FROM timescaledb_osm.tiered_chunks ;

Sample output:


hypertable_schema | hypertable_name |    chunk_name    |      range_start       |       range_end
-------------------+-----------------+------------------+------------------------+------------------------
public            | sample          | _hyper_1_1_chunk | 2023-02-16 00:00:00+00 | 2023-02-23 00:00:00+00
(1 row)

Call untier_chunk:
```
CALL untier_chunk('_hyper_1_1_chunk');
```

See the details of the chunk with timescaledb_information.chunks:


SELECT * FROM timescaledb_information.chunks;

Sample output:


-[ RECORD 1 ]----------+-------------------------
hypertable_schema      | public
hypertable_name        | sample
chunk_schema           | _timescaledb_internal
chunk_name             | _hyper_1_4_chunk
primary_dimension      | ts
primary_dimension_type | timestamp with time zone
range_start            | 2023-02-16 00:00:00+00
range_end              | 2020-03-23 00:00:00+00
range_start_integer    |
range_end_integer      |
is_compressed          | f
chunk_tablespace       |
data_nodes             |

Disable tiering

If you no longer want to use tiered storage for a particular hypertable, drop the associated metadata by calling disable_tiering.

To drop all tiering policies associated with a table, call remove_tiering_policy.
Make sure that there is no tiered data associated with this hypertable:
1. List the tiered chunks associated with this hypertable:
```
select * from timescaledb_osm.tiered_chunks
```
2. If you have any tiered chunks, either untier this data, or drop these chunks from tiered storage.
Use disable_tiering to drop all tiering-related metadata for the hypertable:
```
select disable_tiering('my_hypertable_name');
```
Verify that tiering has been disabled by listing the hypertables that have tiering enabled:
```
select * from timescaledb_osm.tiered_hypertables;
```

Note

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