1. Identify the source of the error: PostgreSQL 42P03 is a syntax error, which means that the query is not valid. To identify the source of the error, you can use the PostgreSQL log files to find the exact query that is causing the error.

2. Fix the syntax error: Once you have identified the query that is causing the error, you can fix the syntax error by making the necessary changes to the query. For example, if the query is missing a closing parenthesis, you can add it to the query.

3. Test the query: After making the necessary changes to the query, you should test it to make sure that it is now valid. You can do this by running the query in the PostgreSQL console and checking the output.

4. Monitor the query: Once the query is fixed, you should monitor it to make sure that it is running correctly. This can be done by using an automated database observability tool, such as Datadog. This tool can help you monitor the query and alert you if there are any issues.

5. Use an automated database observability tool: To ensure that the query is running correctly and to prevent future errors, it is recommended to use an automated database observability tool. This tool can help you monitor the query and alert you if there are any issues. It can also help you identify any potential problems before they become an issue.