How do I force a query to use bind-aware cursor sharing in PostgreSQL?

In PostgreSQL, you can force a query to use bind-aware cursor sharing by utilizing the CURSOR_SHARING parameter. By setting CURSOR_SHARING to ‘FORCE’, PostgreSQL will attempt to share cursors for similar queries with different literal values. This helps reduce the number of distinct cursors and promotes cursor reuse, leading to improved memory usage and performance. Here’s how you can enable bind-aware cursor sharing in PostgreSQL:

  1. Open the PostgreSQL configuration file, usually located at /etc/postgresql/{version}/main/postgresql.conf.
  2. Locate the CURSOR_SHARING parameter, which controls the cursor sharing behavior. If it is not present in the file, you can add it under the appropriate configuration section.
  3. Set the value of CURSOR_SHARING to ‘FORCE’. This tells PostgreSQL to attempt cursor sharing for similar queries with different literal values.

Example:

CURSOR_SHARING = ‘FORCE’

  1. Save the changes to the configuration file.
  2. Restart the PostgreSQL server to apply the new configuration.

Example (on Linux):

sudo systemctl restart postgresql

Once bind-aware cursor sharing is enabled, PostgreSQL will attempt to share cursors for queries that are identical except for literal values. This behavior reduces the memory overhead associated with cursor creation and improves query performance by reusing existing cursors when appropriate.

It’s worth noting that enabling bind-aware cursor sharing may have different effects depending on the specific queries and workload. While it can provide performance benefits, it’s important to test and monitor the impact on your application to ensure it aligns with your specific requirements and query patterns.

Additionally, it’s recommended to consult the PostgreSQL documentation and perform thorough testing to understand the implications and effects of enabling bind-aware cursor sharing in your specific environment.

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.