Can I turn off redo log generation in PostgreSQL?

No, it is not possible to turn off redo log generation in PostgreSQL, as it is a fundamental part of the transactional system that ensures the durability and consistency of your data. The redo logs are used to recover the database in case of a crash or other failure, and disabling them would put your data at risk of being lost or corrupted.

However, you can adjust some configuration parameters that can affect the amount of redo generated, such as the checkpoint frequency, which controls how often PostgreSQL flushes the dirty pages from memory to disk. Reducing the checkpoint frequency may decrease the amount of redo generated, but may also impact the performance of the system.

It’s important to note that while disabling redo log generation may seem like an attractive option for improving performance, it can have serious consequences for the reliability and consistency of your data, and should not be done lightly.

How to tune checkpointing in PostgreSQL?

Tuning checkpointing in PostgreSQL involves adjusting the configuration parameters that control the frequency and behavior of checkpoints. Here are some of the key parameters that can be tuned:

  1. checkpoint_completion_target: This parameter controls how much time is allocated to checkpointing, as a fraction of the time between checkpoints. The default value is 0.5, meaning that half the time between checkpoints is used for checkpointing. Increasing this value can make checkpointing more aggressive, while decreasing it can make it less so.
  2. checkpoint_timeout: This parameter sets the maximum time between checkpoints, in seconds. If a checkpoint hasn’t occurred in this amount of time, one will be triggered regardless of how much data has been written to disk. The default value is 5 minutes (300 seconds).
  3. checkpoint_segments: This parameter controls the maximum number of WAL segments that can be generated between checkpoints. Once this limit is reached, a checkpoint will be triggered. The default value is 3.
  4. max_wal_size: This parameter sets the maximum size of the WAL segment files. Once this limit is reached, a new segment will be created. The default value is 1GB.
  5. min_wal_size: This parameter sets the minimum size of the WAL segment files. The default value is 80MB.
  6. wal_keep_segments: This parameter sets the minimum number of WAL segments that should be retained, even if they’re no longer needed for recovery. This can be useful for point-in-time recovery scenarios.

Adjusting these parameters requires a good understanding of the workload and usage patterns of your PostgreSQL instance, as well as the underlying hardware and storage subsystem. It’s important to test any changes in a non-production environment before rolling them out to production, and to monitor the system closely to ensure that the changes have the desired effect.

About Shiv Iyer 455 Articles
Open Source Database Systems Engineer with a deep understanding of Optimizer Internals, Performance Engineering, Scalability and Data SRE. Shiv currently is the Founder, Investor, Board Member and CEO of multiple Database Systems Infrastructure Operations companies in the Transaction Processing Computing and ColumnStores ecosystem. He is also a frequent speaker in open source software conferences globally.