[BE] Set limits on DB connection lifetime

backend/src/main.rs

@@ -80,6 +80,20 @@ pub async fn init_db() -> Result<(), String> {
     let start = Instant::now();
     let pool = MySqlPoolOptions::new()
         .max_connections(5)
+        /*
+        On some afternoons for some god forsaken reason the idle connections
+        to the db stay alive, but stop responding.
+
+        When this happens, we must restart the server, or wait for all
+        the active connections to timeout.
+
+        Here are some measures to circumvent that:
+        */
+        // Set the maximum wait time for connections to 10 seconds
+        // In practice, the slowest connections take 1.5 seconds to connect
+        .acquire_timeout(std::time::Duration::from_secs(10))
+        // Set the maximum idle time for connections to 10 minutes
+        .idle_timeout(std::time::Duration::from_secs(10 * 60))
         .connect(db_url.as_str())
         .await;
     log::info!("DB Pool connection took: {:?} ms", start.elapsed().as_millis());