1. Identify the source of the error: PostgreSQL 42803 is an error code that indicates a syntax error in the SQL query. 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 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 can test it to make sure it works correctly. You can do this by running the query in a PostgreSQL client and checking the results.

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

5. Use an automated database observability tool: To ensure that the query continues to work correctly, it is recommended to use an automated database observability tool. This tool can monitor the query and alert you if it fails or if there are any performance issues. This can help you quickly identify and fix any issues with the query, preventing them from becoming bigger problems.