1. Identify the source of the PostgreSQL 34000 error:

SELECT * FROM pg_stat_activity;

2. Check the PostgreSQL log file for more information about the error:

tail -f /var/log/postgresql/postgresql-9.6-main.log

3. Check the PostgreSQL configuration file for any settings that may be causing the error:

cat /etc/postgresql/9.6/main/postgresql.conf

4. Check the PostgreSQL system tables for any issues that may be causing the error:

SELECT * FROM pg_stat_activity;

5. Check the PostgreSQL system catalogs for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_class;

6. Check the PostgreSQL system views for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_views;

7. Check the PostgreSQL system functions for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_proc;

8. Check the PostgreSQL system triggers for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_trigger;

9. Check the PostgreSQL system indexes for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_index;

10. Check the PostgreSQL system constraints for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_constraint;

11. Check the PostgreSQL system roles for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_roles;

12. Check the PostgreSQL system tablespaces for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_tablespace;

13. Check the PostgreSQL system statistics for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_statistic;

14. Check the PostgreSQL system locks for any issues that may be causing the error:

SELECT * FROM pg_catalog.pg_locks;

15. Once the source of the PostgreSQL 34000 error has been identified, take the necessary steps to fix the issue.

16. Finally, it is recommended to use an automated database observability tool to monitor and fix the PostgreSQL 34000 in question. This tool can provide real-time insights into the performance and health of the database, as well as alerting when any issues arise. This can help to quickly identify and fix any issues that may arise in the future.