Error
Error Code:
08003
PostgreSQL Error 08003: Connection Does Not Exist
Description
This error indicates that your application attempted to use a database connection that was already closed, invalid, or never properly established. It signifies that the connection object the application holds no longer corresponds to an active session with the PostgreSQL server.
Error Message
connection does not exist
Known Causes
4 known causesConnection Closed Prematurely
The application tried to perform an operation on a connection that was previously closed, either explicitly by the application's code or implicitly by a server timeout or network disconnection.
Server-Side Disconnection
The PostgreSQL server or an intermediary network device closed the connection due to inactivity, resource limits, or a restart, without the client application being aware.
Invalid Connection Handle
The application is attempting to use a connection object that was never successfully opened, or has become corrupted or stale in the application's memory after a previous failure.
Connection Pool Mismanagement
If using a connection pool, the pool might be returning stale or already closed connections, or the application might be mismanaging the lifecycle of connections obtained from the pool.
Solutions
4 solutions available1. Verify PostgreSQL Server Status easy
Ensure the PostgreSQL server process is running and accessible.
1
Check if the PostgreSQL service is running. The command will vary based on your operating system.
sudo systemctl status postgresql2
If the service is not running, start it.
sudo systemctl start postgresql3
On Windows, you can check and start the service through the Services management console (services.msc). Look for 'PostgreSQL' and start the service if it's stopped.
2. Confirm Connection Parameters easy
Double-check that your client is using the correct hostname, port, and database name.
1
Review the connection string or parameters used by your application or client tool. Ensure they match the PostgreSQL server's configuration.
Example connection string: postgresql://user:password@host:port/database2
Verify the default PostgreSQL port is 5432. If your server is configured to use a different port, ensure that port is specified in your connection parameters.
3
Confirm the hostname or IP address is correct and reachable from the client machine. If connecting locally, 'localhost' or '127.0.0.1' should be used.
3. Check Network Connectivity and Firewall Rules medium
Ensure that network pathways between the client and server are open.
1
From the client machine, try to ping the PostgreSQL server's IP address or hostname to confirm basic network reachability.
ping <server_ip_or_hostname>2
Use `telnet` or `nc` (netcat) to test if the PostgreSQL port (default 5432) is open and listening on the server from the client machine.
telnet <server_ip_or_hostname> 54323
If `telnet` or `nc` fails, check firewall rules on both the client and server. Ensure that inbound traffic to the PostgreSQL port is allowed on the server and outbound traffic is allowed from the client.
Example firewall command (ufw on Ubuntu):
sudo ufw status
sudo ufw allow 5432/tcp4
If using cloud providers (AWS, Azure, GCP), verify security group or network access control list (NACL) rules allow traffic on the PostgreSQL port.
4. Review PostgreSQL Configuration for Listen Addresses medium
Verify that PostgreSQL is configured to accept connections from the client's network interface.
1
Locate your `postgresql.conf` file. The location varies by OS and installation method (e.g., `/etc/postgresql/<version>/main/postgresql.conf` on Debian/Ubuntu, or within the data directory).
2
Open `postgresql.conf` and find the `listen_addresses` parameter. Ensure it's set to an IP address or wildcard that includes the interface the client is connecting through.
# Example: listen_addresses = '*' # Listen on all available IP addresses
# Example: listen_addresses = 'localhost, 192.168.1.100' # Listen on localhost and a specific IP3
If you change `listen_addresses`, you must restart the PostgreSQL service for the changes to take effect.
sudo systemctl restart postgresql4
Also, check your `pg_hba.conf` file to ensure there's an entry that allows connections from the client's IP address/range for the specified user and database.
# Example entry in pg_hba.conf:
host all all 192.168.1.0/24 md55
If you modify `pg_hba.conf`, reload the PostgreSQL configuration.
SELECT pg_reload_conf();