compress_chunk.md

api_name	compress_chunk()
excerpt	Manually compress a given chunk
topics	compression
keywords	compression
tags	chunks
api	license type community function
products	cloud mst self_hosted

import Deprecated2180 from "versionContent/_partials/_deprecated_2_18_0.mdx";

compress_chunk() Community

Superseded by convert_to_columnstore(). However, compression APIs are still supported, you do not need to migrate to the hypercore APIs.

The compress_chunk function is used for synchronous compression (or recompression, if necessary) of a specific chunk. This is most often used instead of the add_compression_policy function, when a user wants more control over the scheduling of compression. For most users, we suggest using the policy framework instead.

You can also compress chunks by running the job associated with your compression policy. compress_chunk gives you more fine-grained control by allowing you to target a specific chunk that needs compressing.

You can get a list of chunks belonging to a hypertable using the show_chunks function.

Samples

Compress a single chunk.

SELECT compress_chunk('_timescaledb_internal._hyper_1_2_chunk');

Required arguments

Name	Type	Description
chunk_name	REGCLASS	Name of the chunk to be compressed

Optional arguments

Name	Type	Default	Required	Description
chunk	REGCLASS	-	✔	Name of the chunk to add to the $COLUMNSTORE.
if_not_columnstore	BOOLEAN	true	✖	Set to false so this job fails with an error rather than a warning if chunk is already in the $COLUMNSTORE.
recompress	BOOLEAN	false	✖	Set to true to recompress. In-memory recompression is attempted first; it falls back to internal decompress/compress.

Returns

Column	Type	Description
compress_chunk	REGCLASS	Name of the chunk that was compressed