main: Ensure connection pool size is > 1

Author: Jorge Olivero

node/src/main.rs

@@ -348,6 +348,9 @@ fn async_main() -> impl Future<Item = (), Error = ()> + Send + 'static {
         .parse()
         .expect("Invalid store connection pool size value");
 
+    // Minimum of two connections needed for the pool in order for the Store to bootstrap
+    assert!(store_conn_pool_size > 1);
+
     // Set up Sentry, with release tracking and panic handling;
     // fall back to an empty URL, which will result in no errors being reported
     let sentry_url = env::var_os("THEGRAPH_SENTRY_URL").unwrap_or_else(|| "".into());