diff --git a/src/muz_qe/dl_compiler.cpp b/src/muz_qe/dl_compiler.cpp
index e4528426a..57d9880c0 100644
--- a/src/muz_qe/dl_compiler.cpp
+++ b/src/muz_qe/dl_compiler.cpp
@@ -832,19 +832,19 @@ namespace datalog {
         typedef rule_dependencies::item_set item_set; //set of T
 
         rule_dependencies & m_deps;
-        rule_set const& m_rules;
-        context& m_context;
         item_set & m_removed;
         svector<T> m_stack;
+        ast_mark m_stack_content;
         ast_mark m_visited;
 
         void traverse(T v) {
-            SASSERT(!m_visited.is_marked(v));
-            if (m_removed.contains(v)) {
+            SASSERT(!m_stack_content.is_marked(v)); 
+            if(m_visited.is_marked(v) || m_removed.contains(v)) { 
                 return;
             }
 
             m_stack.push_back(v);
+            m_stack_content.mark(v, true); 
             m_visited.mark(v, true);
 
             const item_set & deps = m_deps.get_deps(v);
@@ -852,49 +852,22 @@ namespace datalog {
             item_set::iterator end = deps.end();
             for(; it!=end; ++it) {
                 T d = *it;
-                if (m_visited.is_marked(d)) {
+                if(m_stack_content.is_marked(d)) { 
                     //TODO: find the best vertex to remove in the cycle
-                    remove_from_stack();
-                    continue;
+                    m_removed.insert(v);
+                    break;
                 }
                 traverse(d);
             }
             SASSERT(m_stack.back()==v);
 
             m_stack.pop_back();
-            m_visited.mark(v, false);
-        }
-
-        void remove_from_stack() {
-            for (unsigned i = 0; i < m_stack.size(); ++i) {
-                func_decl* p = m_stack[i];
-                if (m_context.has_facts(p)) {
-                    m_removed.insert(p);
-                    return;
-                }
-
-                rule_vector const& rules = m_rules.get_predicate_rules(p);
-                unsigned stratum = m_rules.get_predicate_strat(p);
-                for (unsigned j = 0; j < rules.size(); ++j) {
-                    rule const& r = *rules[j];
-                    bool ok = true;
-                    for (unsigned k = 0; ok && k < r.get_uninterpreted_tail_size(); ++k) {
-                        ok = m_rules.get_predicate_strat(r.get_decl(k)) < stratum;
-                    }
-                    if (ok) {
-                        m_removed.insert(p);
-                        return;
-                    }
-                }
-            }
-
-            // nothing was found.
-            m_removed.insert(m_stack.back());
+            m_stack_content.mark(v, false); 
         }
 
     public:
-        cycle_breaker(rule_dependencies & deps, rule_set const& rules, context& ctx, item_set & removed) 
-            : m_deps(deps), m_rules(rules), m_context(ctx), m_removed(removed) { SASSERT(removed.empty()); }
+        cycle_breaker(rule_dependencies & deps, item_set & removed) 
+            : m_deps(deps), m_removed(removed) { SASSERT(removed.empty()); }
 
         void operator()() {
             rule_dependencies::iterator it = m_deps.begin();
@@ -916,7 +889,7 @@ namespace datalog {
 
         rule_dependencies deps(m_rule_set.get_dependencies());
         deps.restrict(preds);
-        cycle_breaker(deps, m_rule_set, m_context, global_deltas)();
+        cycle_breaker(deps, global_deltas)();
         VERIFY( deps.sort_deps(ordered_preds) );
 
         //the predicates that were removed to get acyclic induced subgraph are put last
@@ -1052,12 +1025,17 @@ namespace datalog {
         }
 
         func_decl_vector preds_vector;
-        func_decl_set global_deltas;
+        func_decl_set global_deltas_dummy;
 
-        detect_chains(head_preds, preds_vector, global_deltas);
+        detect_chains(head_preds, preds_vector, global_deltas_dummy);
 
+        /*
+          FIXME: right now we use all preds as global deltas for correctness purposes
         func_decl_set local_deltas(head_preds);
         set_difference(local_deltas, global_deltas);
+        */
+        func_decl_set local_deltas;
+        func_decl_set global_deltas(head_preds);
 
         pred2idx d_global_src;  //these deltas serve as sources of tuples for rule evaluation inside the loop
         get_fresh_registers(global_deltas, d_global_src);
diff --git a/src/muz_qe/dl_compiler.h b/src/muz_qe/dl_compiler.h
index 8f40f814a..78b4623de 100644
--- a/src/muz_qe/dl_compiler.h
+++ b/src/muz_qe/dl_compiler.h
@@ -42,7 +42,6 @@ namespace datalog {
         typedef u_map<unsigned> int2int;
         typedef u_map<unsigned_vector> int2ints;
         typedef obj_map<func_decl, reg_idx> pred2idx;
-//        typedef map<func_decl *, reg_idx, ptr_hash<func_decl>,ptr_eq<func_decl> > pred2idx;
         typedef unsigned_vector var_vector;
         typedef ptr_vector<func_decl> func_decl_vector;
 
diff --git a/src/muz_qe/dl_instruction.cpp b/src/muz_qe/dl_instruction.cpp
index 296fa95f3..b103d743e 100644
--- a/src/muz_qe/dl_instruction.cpp
+++ b/src/muz_qe/dl_instruction.cpp
@@ -359,21 +359,7 @@ namespace datalog {
                 r2.get_signature().output(ctx.get_rel_context().get_manager(), tout);
                 tout<<":"<<r2.get_size_estimate_rows()<<" ->\n";);
 
-            try {
-                ctx.set_reg(m_res, (*fn)(r1, r2));
-            }
-            catch(...)
-            {
-                std::string annotation;
-                unsigned sz;
-                ctx.get_register_annotation(m_rel1, annotation);
-                sz = ctx.reg(m_rel1)?ctx.reg(m_rel1)->get_size_estimate_rows():0;
-                std::cout << m_rel1 << "\t" << sz << "\t" << annotation << "\n";
-                ctx.get_register_annotation(m_rel2, annotation);
-                sz = ctx.reg(m_rel2)?ctx.reg(m_rel2)->get_size_estimate_rows():0;
-                std::cout << m_rel2 << "\t" << sz << "\t" << annotation << "\n";
-                throw;
-            }
+            ctx.set_reg(m_res, (*fn)(r1, r2));
 
             TRACE("dl", 
                 ctx.reg(m_res)->get_signature().output(ctx.get_rel_context().get_manager(), tout);
diff --git a/src/muz_qe/dl_mk_filter_rules.cpp b/src/muz_qe/dl_mk_filter_rules.cpp
index 8ab8412c0..932a644ab 100644
--- a/src/muz_qe/dl_mk_filter_rules.cpp
+++ b/src/muz_qe/dl_mk_filter_rules.cpp
@@ -152,9 +152,6 @@ namespace datalog {
     }
 
     rule_set * mk_filter_rules::operator()(rule_set const & source) {
-        if (!m_context.get_params().filter_rules()) {
-            return 0;
-        }
         m_tail2filter.reset();
         m_result           = alloc(rule_set, m_context);
         m_modified         = false;
diff --git a/src/muz_qe/dl_rule_transformer.cpp b/src/muz_qe/dl_rule_transformer.cpp
index 21021ca43..0cad08cb4 100644
--- a/src/muz_qe/dl_rule_transformer.cpp
+++ b/src/muz_qe/dl_rule_transformer.cpp
@@ -107,9 +107,6 @@ namespace datalog {
                 tout << typeid(p).name()<<":\n";
                 new_rules->display(tout);
             );
-            IF_VERBOSE(1, new_rules->get_rule(0)->display(m_context, verbose_stream() << typeid(p).name() <<"\n"););
-            IF_VERBOSE(1, verbose_stream() << new_rules->get_dependencies().begin()->m_key->get_name() << "\n";);
-
         }
         if (modified) {
             rules.replace_rules(*new_rules);
diff --git a/src/muz_qe/fixedpoint_params.pyg b/src/muz_qe/fixedpoint_params.pyg
index fd7dbdcae..774559cdb 100644
--- a/src/muz_qe/fixedpoint_params.pyg
+++ b/src/muz_qe/fixedpoint_params.pyg
@@ -13,7 +13,6 @@ def_module_params('fixedpoint',
                           ('unbound_compressor', BOOL, True, "auxiliary relations will be introduced to avoid unbound variables in rule heads"),
                           ('similarity_compressor', BOOL, True, "(DATALOG) rules that differ only in values of constants will be merged into a single rule"),
                           ('similarity_compressor_threshold', UINT, 11, "(DATALOG) if similarity_compressor is on, this value determines how many similar rules there must be in order for them to be merged"),
-                          ('filter_rules', BOOL, True, "(DATALOG) apply filter compression on rules"),
                           ('all_or_nothing_deltas', BOOL, False, "(DATALOG) compile rules so that it is enough for the delta relation in union and widening operations to determine only whether the updated relation was modified or not"),
                           ('compile_with_widening', BOOL, False, "(DATALOG) widening will be used to compile recursive rules"),
                           ('eager_emptiness_checking', BOOL, True, "(DATALOG) emptiness of affected relations will be checked after each instruction, so that we may ommit unnecessary instructions"),
diff --git a/src/muz_qe/rel_context.cpp b/src/muz_qe/rel_context.cpp
index 07633c536..b42adca79 100644
--- a/src/muz_qe/rel_context.cpp
+++ b/src/muz_qe/rel_context.cpp
@@ -116,12 +116,10 @@ namespace datalog {
         TRACE("dl", m_context.display(tout););
 
         while (true) {
-            
             m_ectx.reset();
             m_code.reset();
             termination_code.reset();
             m_context.ensure_closed();
-            IF_VERBOSE(1, verbose_stream() << "num rules: " << m_context.get_rules().get_num_rules() << "\n";);
             m_context.transform_rules();
             if (m_context.canceled()) {
                 result = l_undef;
@@ -184,9 +182,7 @@ namespace datalog {
             scoped_query.reset();
         }
         m_context.record_transformed_rules();
-        TRACE("dl", m_ectx.report_big_relations(100, tout););
-        m_code.process_all_costs();
-        m_code.make_annotations(m_ectx);        
+        TRACE("dl", display_profile(tout););
         return result;
     }
  
@@ -484,7 +480,10 @@ namespace datalog {
         get_rmanager().display(out);
     }
 
-    void rel_context::display_profile(std::ostream& out) const {
+    void rel_context::display_profile(std::ostream& out) {
+        m_code.make_annotations(m_ectx);
+        m_code.process_all_costs();  
+
         out << "\n--------------\n";
         out << "Instructions\n";
         m_code.display(*this, out);
diff --git a/src/muz_qe/rel_context.h b/src/muz_qe/rel_context.h
index 3e019cb50..8e4c6f2de 100644
--- a/src/muz_qe/rel_context.h
+++ b/src/muz_qe/rel_context.h
@@ -105,7 +105,7 @@ namespace datalog {
         void display_output_facts(rule_set const& rules, std::ostream & out) const;
         void display_facts(std::ostream & out) const;
 
-        void display_profile(std::ostream& out) const;
+        void display_profile(std::ostream& out);
 
         lbool saturate();