diff --git a/godel-script/godel-frontend/src/engine.cpp b/godel-script/godel-frontend/src/engine.cpp
index 461fde8..dbf8cff 100644
--- a/godel-script/godel-frontend/src/engine.cpp
+++ b/godel-script/godel-frontend/src/engine.cpp
@@ -400,6 +400,12 @@ void engine::run_souffle(const std::string& souffle_content,
         argv.push_back("--index-stats");
     }
 
+    // magic set, it's not suggested to use it on all the predicates
+    // argv.push_back("--magic-transform=*");
+
+    // need latest version of souffle to make it more efficient
+    // argv.push_back("--jobs=4");
+
     // enable souffle auto schedule, for experimental use only
     // argv.push_back("--auto-schedule=souffle.prof.log");
 
diff --git a/godel-script/godel-frontend/src/ir/ir_gen.cpp b/godel-script/godel-frontend/src/ir/ir_gen.cpp
index 09ae8fc..9388e3f 100644
--- a/godel-script/godel-frontend/src/ir/ir_gen.cpp
+++ b/godel-script/godel-frontend/src/ir/ir_gen.cpp
@@ -538,11 +538,23 @@ void ir_gen::emit_schema_get_field() {
                 );
                 call->add_arg(lir::inst_value_t::variable("self"));
                 call->add_arg(lir::inst_value_t::default_value());
+
+                // enable particular index
+                // for z in pred(_, _, z, _, _)
+                // it's better to use pred(x, y, z, _, _) to auto generate index in souffle
+                int count = 0;
+                bool reach_field = false;
                 for(const auto& f : sc.second.ordered_fields) {
-                    call->add_arg(f==field?
-                        lir::inst_value_t::variable("ret?result"):
-                        lir::inst_value_t::default_value()
+                    if (f == field) {
+                        reach_field = true;
+                    }
+                    call->add_arg(f==field
+                        ? lir::inst_value_t::variable("ret?result")
+                        : reach_field
+                            ? lir::inst_value_t::default_value()
+                            : lir::inst_value_t::variable("?" + std::to_string(count))
                     );
+                    ++count;
                 }
                 rule_impl->get_block()->add_new_content(call);
             }
@@ -1102,6 +1114,16 @@ void ir_gen::report_ignored_DO_schema_data_constraint() {
     err.warn_ignored_DO_schema(ignored_DO_schema);
 }
 
+void ir_gen::report_no_output_predicate() {
+    if (irc.souffle_output.size() || irc.annotated_output.size()) {
+        return;
+    }
+    err.warn(
+        "no output predicate is found, "
+        "execution will not generate any outputs or output files."
+    );
+}
+
 bool ir_gen::visit_number_literal(number_literal* node) {
     value_stack.push_back({
         data_kind::literal,
@@ -2488,6 +2510,7 @@ void ir_gen::generate(const cli::configure& config, ast_root* root) {
     root->accept(this);
 
     report_ignored_DO_schema_data_constraint();
+    report_no_output_predicate();
 }
 
 }
\ No newline at end of file
diff --git a/godel-script/godel-frontend/src/ir/ir_gen.h b/godel-script/godel-frontend/src/ir/ir_gen.h
index 814e620..201dc87 100644
--- a/godel-script/godel-frontend/src/ir/ir_gen.h
+++ b/godel-script/godel-frontend/src/ir/ir_gen.h
@@ -202,6 +202,7 @@ class ir_gen: public ast_visitor {
 private:
     std::unordered_set<std::string> ignored_DO_schema;
     void report_ignored_DO_schema_data_constraint();
+    void report_no_output_predicate();
 
 private:
     bool visit_number_literal(number_literal*) override;
diff --git a/godel-script/godel-frontend/src/semantic.cpp b/godel-script/godel-frontend/src/semantic.cpp
index 4e2e8ab..b183f80 100644
--- a/godel-script/godel-frontend/src/semantic.cpp
+++ b/godel-script/godel-frontend/src/semantic.cpp
@@ -2359,7 +2359,7 @@ bool semantic::check_single_argument(expr* argument, const symbol& param) {
     }
 
     // check type match
-    if (param!=expr_infer.type) {
+    if (param != expr_infer.type && !expr_infer.type.is_err()) {
         err.err(argument->get_location(),
             "expected \"" + param.full_path_name() +
             "\" but get \"" + expr_infer.type.full_path_name() + "\"."
@@ -2864,7 +2864,8 @@ void semantic::query_check(query_decl* node) {
             .is_set = false
         };
 
-        if (initial_infer.type!=from_variable_type) {
+        if (initial_infer.type != from_variable_type &&
+            !initial_infer.type.is_err()) {
             err.err(i->get_init_value()->get_location(),
                 "expected \"" + from_variable_type.full_path_name() +
                 "\" but get \"" + initial_infer.type.full_path_name() +