feat(monero-rpc-pool): Add randomness to node selection, prefer established TCP circuits

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - GUI: Speedup startup by concurrently bootstrapping Tor and requesting the user to select a wallet
 - GUI: Add white background to QR code modal to make it better scannable
 - GUI + CLI + ASB: Add `/dns4/rendezvous.observer/tcp/8888/p2p/12D3KooWMjceGXrYuGuDMGrfmJxALnSDbK4km6s1i1sJEgDTgGQa` to the default list of rendezvous points
+- GUI + CLI + ASB: Monero RPC pool now prioritizes nodes with pre-established TCP connections
 
 ## [3.0.0-beta.6] - 2025-08-07
 

monero-rpc-pool/src/bin/stress_test_downloader.rs

@@ -143,7 +143,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let client = Arc::new(
         reqwest::Client::builder()
-            .timeout(std::time::Duration::from_secs(3 * 60 + 30)) // used in wallet2
+            .timeout(std::time::Duration::from_secs(10 * 60 + 30)) // used in wallet2
             .build()
             .expect("Failed to build reqwest client"),
     );

monero-rpc-pool/src/connection_pool.rs

@@ -175,4 +175,18 @@ impl ConnectionPool {
             }
         }
     }
+
+    /// Check if there's an available (unlocked) connection for the given key.
+    pub async fn has_available_connection(&self, key: &StreamKey) -> bool {
+        let map = self.inner.read().await;
+        if let Some(vec_lock) = map.get(key) {
+            let vec = vec_lock.read().await;
+            for sender_mutex in vec.iter() {
+                if sender_mutex.try_lock().is_ok() {
+                    return true;
+                }
+            }
+        }
+        false
+    }
 }

monero-rpc-pool/src/database.rs

@@ -232,38 +232,52 @@ impl Database {
     }
 
     /// Get top nodes based on success rate
+    /// Adds randomness
     pub async fn get_top_nodes_by_recent_success(
         &self,
         network: &str,
         limit: i64,
     ) -> Result<Vec<NodeAddress>> {
+        // Randomized ordering: r = max of 3 Uniform(0,1) (biased toward 1).
+        // Rank by (base_score * r) so top nodes remain preferred but can shuffle.
+        // r is drawn once per row in the CTE and reused in ORDER BY.
+        // Increase RANDOM() terms in MAX(...) to strengthen the bias.
         let rows = sqlx::query!(
             r#"
-            SELECT 
-                n.scheme,
-                n.host,
-                n.port
-            FROM monero_nodes n
-            LEFT JOIN (
+            WITH scored AS (
                 SELECT 
-                    node_id,
-                    SUM(CASE WHEN was_successful THEN 1 ELSE 0 END) as success_count,
-                    SUM(CASE WHEN NOT was_successful THEN 1 ELSE 0 END) as failure_count
-                FROM (
-                    SELECT node_id, was_successful
-                    FROM health_checks 
-                    ORDER BY timestamp DESC 
-                    LIMIT 1000
-                ) recent_checks
-                GROUP BY node_id
-            ) stats ON n.id = stats.node_id
-            WHERE n.network = ?
-            ORDER BY 
-                CASE 
-                    WHEN (COALESCE(stats.success_count, 0) + COALESCE(stats.failure_count, 0)) > 0 
-                    THEN CAST(COALESCE(stats.success_count, 0) AS REAL) / CAST(COALESCE(stats.success_count, 0) + COALESCE(stats.failure_count, 0) AS REAL)
-                    ELSE 0.0 
-                END DESC
+                    n.scheme,
+                    n.host,
+                    n.port,
+                    CASE 
+                        WHEN (COALESCE(stats.success_count, 0) + COALESCE(stats.failure_count, 0)) > 0 
+                        THEN CAST(COALESCE(stats.success_count, 0) AS REAL) / CAST(COALESCE(stats.success_count, 0) + COALESCE(stats.failure_count, 0) AS REAL)
+                        ELSE 0.0 
+                    END as base_score,
+                    MAX(
+                        ABS(RANDOM()) / CAST(0x7fffffffffffffff AS REAL),
+                        ABS(RANDOM()) / CAST(0x7fffffffffffffff AS REAL),
+                        ABS(RANDOM()) / CAST(0x7fffffffffffffff AS REAL)
+                    ) as r
+                FROM monero_nodes n
+                LEFT JOIN (
+                    SELECT 
+                        node_id,
+                        SUM(CASE WHEN was_successful THEN 1 ELSE 0 END) as success_count,
+                        SUM(CASE WHEN NOT was_successful THEN 1 ELSE 0 END) as failure_count
+                    FROM (
+                        SELECT node_id, was_successful
+                        FROM health_checks 
+                        ORDER BY timestamp DESC 
+                        LIMIT 1000
+                    ) recent_checks
+                    GROUP BY node_id
+                ) stats ON n.id = stats.node_id
+                WHERE n.network = ?
+            )
+            SELECT scheme, host, port
+            FROM scored
+            ORDER BY (base_score * r) DESC, r DESC
             LIMIT ?
             "#,
             network,