Fix PostgreSQL database handling and enhance connection logging in proxy

Author: hasirciogluhq

CHANGELOG.md

@@ -82,6 +82,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Updated test and development scripts to use new configuration format
 
 ### Fixed
+- **PostgreSQL Database Parameter Handling**: Complete fix for database defaulting logic
+  - Defaults to "postgres" when client omits database name
+  - Detects when client auto-fills database with username (common psql behavior)
+  - Prevents "database does not exist" errors when username contains deployment_id suffix
+  - Example: `database=postgres.team-1992252154561` now correctly becomes `database=postgres`
+- **PostgreSQL Resolver**: Uses correct database type (postgresql) instead of mysql for routing
+- **StartupMessage Rebuild**: Simplified logic - now rebuilds on every handshake for consistency
+  - Every TCP connection gets a fresh StartupMessage
+  - Eliminates unnecessary optimization that caused edge cases
+  - Ensures username parsing and database defaulting always work correctly
+- **Enhanced Logging**: Added comprehensive logging for connection parameters and username parsing
 - Multi-instance TLS certificate creation race conditions
 - Kubernetes discovery from non-Kubernetes runtimes
 - Certificate lifecycle management issues

cmd/proxy/internal/proxy/postgresql/proxy.go

@@ -213,9 +213,14 @@ func (p *PostgresProxy) handshake(conn net.Conn) (core.RoutingMetadata, net.Conn
 		value = value[:len(value)-1] // Trim null byte
 
 		params[key] = value
+		logger.Info("StartupMessage param", "key", key, "value", value, "remote_addr", conn.RemoteAddr())
 	}
 
 	// Parse username to extract deployment_id and pool status
+	// Format: username.deployment_id[.pool]
+	// Examples:
+	//   alice.db-prod.pool     → username=alice, deployment_id=db-prod, pooled=true
+	//   bob.team-1992252154561 → username=bob, deployment_id=team-1992252154561, pooled=false
 	if user, ok := params["user"]; ok {
 		logger.Info("Connection requested", "user", user, "remote_addr", conn.RemoteAddr())
 		parts := strings.Split(user, ".")
@@ -236,28 +241,43 @@ func (p *PostgresProxy) handshake(conn net.Conn) (core.RoutingMetadata, net.Conn
 		}
 	}
 
-	var rawStartupMsg []byte
+	// Default database to postgres if not provided OR if it equals the original user
+	// Some PostgreSQL clients (like psql) automatically use username as database when not specified
+	// This causes issues when username is "postgres.team-1992252154561" and gets used as database name
+	// We detect this case and default to "postgres" database instead
+	originalUser := params["user"]
+	if dbName, ok := params["database"]; !ok || dbName == "" || dbName == originalUser {
+		params["database"] = "postgres"
+		logger.Info("Database defaulted to postgres", "original_db", dbName, "remote_addr", conn.RemoteAddr())
+	}
 
-	if originalUser, ok := params["user"]; ok {
-		if newUser, ok := params["username"]; ok && newUser != originalUser {
-			// Rebuild startup message with new username
-			protocolVersion := binary.BigEndian.Uint32(payload[0:4])
-			buildParams := make(map[string]string)
-			for k, v := range params {
-				if k != "deployment_id" && k != "pooled" && k != "username" {
-					buildParams[k] = v
-				}
-			}
-			buildParams["user"] = newUser
-			rawStartupMsg = rebuildStartupMessage(protocolVersion, buildParams)
-		} else {
-			// Use original message
-			rawStartupMsg = make([]byte, len(header)+len(payload))
-			copy(rawStartupMsg, header)
-			copy(rawStartupMsg[4:], payload)
+	// Always rebuild startup message with parsed params
+	// Every PostgreSQL connection performs a fresh handshake, so we rebuild the StartupMessage
+	// to send the correct username (without deployment_id/pool suffix) and database to the backend
+	protocolVersion := binary.BigEndian.Uint32(payload[0:4])
+	buildParams := make(map[string]string)
+
+	// Copy all params except internal metadata (user will be set separately)
+	// Exclude: deployment_id, pooled, username (internal routing metadata)
+	// Include: database, client_encoding, application_name, etc.
+	for k, v := range params {
+		if k != "deployment_id" && k != "pooled" && k != "username" && k != "user" {
+			buildParams[k] = v
 		}
 	}
 
+	// Use parsed username (without deployment_id suffix) or fallback to original
+	// Backend expects: "alice" not "alice.db-prod.pool"
+	if username, ok := params["username"]; ok && username != "" {
+		buildParams["user"] = username
+		logger.Info("Using parsed username", "username", username, "database", buildParams["database"], "remote_addr", conn.RemoteAddr())
+	} else if originalUser, ok := params["user"]; ok {
+		buildParams["user"] = originalUser
+		logger.Info("Using original username", "user", originalUser, "database", buildParams["database"], "remote_addr", conn.RemoteAddr())
+	}
+
+	// Rebuild the binary StartupMessage packet with modified parameters
+	rawStartupMsg := rebuildStartupMessage(protocolVersion, buildParams)
 	return core.RoutingMetadata(params), conn, rawStartupMsg, nil
 }
 

scripts/local-deploy/postgresql.sh

@@ -39,18 +39,20 @@ else
     echo "✅ Image should be available locally"
 fi
 
+
+
+# Delete the DaemonSet to use the new image
+echo "D}} Deleting xdatabase-proxy DaemonSet..."
+kubectl delete daemonset/xdatabase-proxy -n xdatabase-proxy
+
+sleep 1
+
 # Apply Kubernetes manifests
 echo "🚀 Deploying to Kubernetes..."
 kubectl apply -f "kubernetes/examples/local-test/postgresql.yaml"
 
-# Wait a moment for the deployment to register
-sleep 2
-
-# Restart the DaemonSet to use the new image
-echo "🔄 Restarting xdatabase-proxy DaemonSet..."
-kubectl rollout restart daemonset/xdatabase-proxy -n xdatabase-proxy
+sleep 3
 
-# Wait for rollout to complete
 echo "⏳ Waiting for rollout to complete..."
 kubectl rollout status daemonset/xdatabase-proxy -n xdatabase-proxy --timeout=120s