Question: What are the default settings in the postgres.conf file?

Answer

The postgres.conf file is the main configuration file for a PostgreSQL database server. It contains settings that control many aspects of the PostgreSQL server's behavior, including memory usage, connection settings, logging, and more. Below are some key default settings typically found in a postgres.conf file:

Memory and Performance

1. shared_buffers - Determines the amount of memory the database server uses for shared memory buffers. The default is typically set to 128MB.

   shared_buffers = 128MB

2. work_mem - Sets the amount of memory used for query operations such as sorting and joins. The default setting is usually small, around 4MB.

   work_mem = 4MB

Connection Settings

3. max_connections - Specifies the maximum number of concurrent connections to the database server. Its default is commonly 100.

   max_connections = 100

4. listen_addresses - Configures which IP address(es) the server listens on; '*' means listen on all available addresses.

   listen_addresses = 'localhost'

Logging

5. log_destination - Determines where logs will be written (e.g., stderr, csvlog). By default, logs are written to stderr.

   log_destination = 'stderr'

6. logging_collector - Used to collect log output and redirect it into log files. The default is typically off.

   logging_collector = off

These settings can be tuned based on the specific needs and resources of your environment. To change these defaults, edit the postgres.conf file and reload the PostgreSQL server for changes to take effect:

pg_ctl reload

For a comprehensive list of all configurable parameters and their explanations, refer to the official PostgreSQL documentation.