decompress_chunk()

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If you need to modify or add data to a chunk that has already been compressed, you need to decompress the chunk first. This is especially useful for backfilling old data.

important

Before decompressing chunks, stop any compression policy on the hypertable you are decompressing. You can use SELECT alter_job(JOB_ID, scheduled => false); to prevent scheduled execution. When you finish backfilling or updating data, turn the policy back on. The database automatically recompresses your chunks in the next scheduled job.

Required arguments

Name	Type	Description
`chunk_name`	`REGCLASS`	Name of the chunk to be decompressed.

Optional arguments

Name	Type	Description
`if_compressed`	`BOOLEAN`	Setting to true skips chunks that are not compressed. Defaults to false.

Sample usage

Decompress a single chunk:


SELECT decompress_chunk('_timescaledb_internal._hyper_2_2_chunk');

Decompress all compressed chunks in a hypertable named metrics:


SELECT decompress_chunk(c, true) FROM show_chunks('metrics') c;