feat: reprepare and retry prepared statements

pgdog/src/backend/mod.rs

@@ -15,6 +15,7 @@ pub mod replication;
 pub mod schema;
 pub mod server;
 pub mod server_options;
+pub mod server_state;
 pub mod stats;
 
 pub use connect_reason::ConnectReason;

pgdog/src/backend/prepared_statements.rs

@@ -103,6 +103,18 @@ impl PreparedStatements {
                 self.state.add_ignore('1');
                 Ok(())
             }
+            ProtocolMessage::Sync(_) => {
+                self.state.add_ignore('Z');
+                Ok(())
+            }
+            ProtocolMessage::Close(_) => {
+                self.state.add_ignore('3');
+                Ok(())
+            }
+            ProtocolMessage::Bind(_) => {
+                self.state.add_ignore('2');
+                Ok(())
+            }
             _ => Err(Error::UnsupportedHandleIgnore(request.code())),
         }
     }

pgdog/src/backend/protocol/state.rs

@@ -129,6 +129,15 @@ impl ProtocolState {
         self.simulated.push_back(message);
     }
 
+    /// Clear the state queue. Can be used for when a
+    /// statement fails and we have to retry it:
+    /// 1. Clear the state queue
+    /// 2. Fix up the statement (eg deallocate + reprepare)
+    /// 3. Run the statement again, building up the state again
+    pub(crate) fn clear(&mut self) {
+        self.queue.clear();
+    }
+
     /// Get a simulated message from the execution queue.
     ///
     /// Returns a message only if it should be returned at the current state