Troubleshooting

This section contains some ideas for troubleshooting common problems experienced with compression.

Failed to start a background worker

`

  1. "<TYPE_OF_BACKGROUND_JOB>": failed to start a background worker

`

You might see this error message in the logs if background workers aren’t properly configured.

To fix this error, make sure that max_worker_processes, max_parallel_workers, and timescaledb.max_background_workers are properly set. timescaledb.max_background_workers should equal the number of databases plus the number of concurrent background workers. max_worker_processes should equal the sum of timescaledb.max_background_workers and max_parallel_workers.

For more information, see the worker configuration docs.

Cannot refresh compressed chunks of a continuous aggregate

`

  1. ERROR:  cannot update/delete rows from chunk <CHUNK_NAME> as it is compressed

`

Compressed chunks of a continuous aggregate can’t be refreshed. This follows from a general limitation where compressed chunks can’t be updated or deleted.

If you receive historical data and must refresh a compressed region, first decompress the chunk. Then manually run refresh_continuous_aggregate.

Scheduled jobs stop running

Your scheduled jobs might stop running for various reasons. On self-hosted TimescaleDB, you can fix this by restarting background workers:

  2. SELECT _timescaledb_internal.start_background_workers();

On Timescale Cloud and Managed Service for TimescaleDB, restart background workers by doing one of the following:

  • Run SELECT timescaledb_pre_restore(), followed by SELECT timescaledb_post_restore().
  • Power the service off and on again. This might cause a downtime of a few minutes while the service restores from backup and replays the write-ahead log.