Could not access file “pg_stat_statements”: no such file or directory

Explanation:

When encountering the error message “could not access file ‘pg_stat_statements’: no such file or directory” in PostgreSQL, it means that the extension ‘pg_stat_statements’ is not installed or enabled in your database.

The ‘pg_stat_statements’ extension provides statistics about SQL statements executed by a PostgreSQL server. It can be very useful for performance analysis and optimization.

Fix:

To resolve this issue, you need to follow these steps:

1. Make sure you have superuser privileges or are logged in as a user with appropriate permissions.
2. Connect to your PostgreSQL database using a PostgreSQL client or command-line tool.
3. Check if the ‘pg_stat_statements’ extension is installed by running the following query:

SELECT name, default_version, installed_version FROM pg_available_extensions WHERE name = 'pg_stat_statements';

If the query returns no rows, it means the extension is not installed. In that case, proceed to step 4.

If the query returns a row, but the ‘installed_version’ column is empty or different from the ‘default_version’, it means the extension is installed but not enabled. Proceed to step 5 in that case.

4. If the ‘pg_stat_statements’ extension is not installed, you can install it by running the following command:

CREATE EXTENSION pg_stat_statements;

5. If the extension is installed but not enabled, you can enable it by running the following command:

ALTER EXTENSION pg_stat_statements SET SCHEMA public;

6. After enabling the extension, you can verify its installation and status by running the query from step 3 again. This time, it should return a row with the correct ‘installed_version’.

Once the ‘pg_stat_statements’ extension is installed and enabled, you should be able to access the file “pg_stat_statements” without encountering the “no such file or directory” error.

Example:

CREATE EXTENSION pg_stat_statements;
ALTER EXTENSION pg_stat_statements SET SCHEMA public;