fix: force sqlite connection singleton to avoid database lock error

src/meta/node/src/server.rs

@@ -174,9 +174,17 @@ pub async fn rpc_serve(
             )
         }
         MetaStoreBackend::Sql { endpoint } => {
+            let max_connection = if DbBackend::Sqlite.is_prefix_of(&endpoint) {
+                // Due to the fact that Sqlite is prone to the error "(code: 5) database is locked" under concurrent access,
+                // here we forcibly specify the number of connections as 1.
+                1
+            } else {
+                10
+            };
+
             let mut options = sea_orm::ConnectOptions::new(endpoint);
             options
-                .max_connections(20)
+                .max_connections(max_connection)
                 .connect_timeout(Duration::from_secs(10))
                 .idle_timeout(Duration::from_secs(30));
             let conn = sea_orm::Database::connect(options).await?;