diff --git a/lib/filterx/expr-compound.c b/lib/filterx/expr-compound.c
index b324894c6..35f6d7d83 100644
--- a/lib/filterx/expr-compound.c
+++ b/lib/filterx/expr-compound.c
@@ -26,6 +26,8 @@
 #include "filterx/filterx-eval.h"
 #include "filterx/object-primitive.h"
 #include "scratch-buffers.h"
+#include "stats/stats-registry.h"
+#include "stats/stats-cluster-single.h"
 
 #include <stdarg.h>
 
@@ -35,6 +37,7 @@ typedef struct _FilterXCompoundExpr
   /* whether this is a statement expression */
   gboolean return_value_of_last_expr;
   GPtrArray *exprs;
+
 } FilterXCompoundExpr;
 
 static gboolean
@@ -148,6 +151,12 @@ _init(FilterXExpr *s, GlobalConfig *cfg)
         }
     }
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_compound_evals_total", NULL, 0);
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   return filterx_expr_init_method(s, cfg);
 }
 
@@ -156,6 +165,12 @@ _deinit(FilterXExpr *s, GlobalConfig *cfg)
 {
   FilterXCompoundExpr *self = (FilterXCompoundExpr *) s;
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_compound_evals_total", NULL, 0);
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   for (gint i = 0; i < self->exprs->len; i++)
     {
       FilterXExpr *expr = g_ptr_array_index(self->exprs, i);
diff --git a/lib/filterx/expr-condition.c b/lib/filterx/expr-condition.c
index 75011631d..95494fe34 100644
--- a/lib/filterx/expr-condition.c
+++ b/lib/filterx/expr-condition.c
@@ -25,6 +25,8 @@
 #include "filterx/expr-literal.h"
 #include "filterx/object-primitive.h"
 #include "scratch-buffers.h"
+#include "stats/stats-registry.h"
+#include "stats/stats-cluster-single.h"
 
 typedef struct _FilterXConditional FilterXConditional;
 
@@ -57,6 +59,12 @@ _init(FilterXExpr *s, GlobalConfig *cfg)
       return FALSE;
     }
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_condition_evals_total", NULL, 0);
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   return filterx_expr_init_method(s, cfg);
 }
 
@@ -66,6 +74,12 @@ _deinit(FilterXExpr *s, GlobalConfig *cfg)
 {
   FilterXConditional *self = (FilterXConditional *) s;
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_condition_evals_total", NULL, 0);
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   filterx_expr_deinit(self->condition, cfg);
   filterx_expr_deinit(self->true_branch, cfg);
   filterx_expr_deinit(self->false_branch, cfg);
diff --git a/lib/filterx/expr-function.c b/lib/filterx/expr-function.c
index 408051995..013bcf7e0 100644
--- a/lib/filterx/expr-function.c
+++ b/lib/filterx/expr-function.c
@@ -35,6 +35,7 @@
 #include "plugin.h"
 #include "cfg.h"
 #include "mainloop.h"
+#include "stats/stats-cluster-single.h"
 
 GQuark
 filterx_function_error_quark(void)
@@ -227,12 +228,26 @@ filterx_simple_function_new(const gchar *function_name, FilterXFunctionArgs *arg
 gboolean
 filterx_function_init_method(FilterXFunction *s, GlobalConfig *cfg)
 {
+  stats_lock();
+  StatsClusterKey sc_key;
+  StatsClusterLabel labels[] = { stats_cluster_label("name", s->function_name) };
+  stats_cluster_single_key_set(&sc_key, "fx_func_evals_total", labels, G_N_ELEMENTS(labels));
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &s->super.eval_count);
+  stats_unlock();
+
   return filterx_expr_init_method(&s->super, cfg);
 }
 
 void
 filterx_function_deinit_method(FilterXFunction *s, GlobalConfig *cfg)
 {
+  stats_lock();
+  StatsClusterKey sc_key;
+  StatsClusterLabel labels[] = { stats_cluster_label("name", s->function_name) };
+  stats_cluster_single_key_set(&sc_key, "fx_func_evals_total", labels, G_N_ELEMENTS(labels));
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &s->super.eval_count);
+  stats_unlock();
+
   filterx_expr_deinit_method(&s->super, cfg);
 }
 
diff --git a/lib/filterx/expr-function.h b/lib/filterx/expr-function.h
index 819e0b736..0c1085f2a 100644
--- a/lib/filterx/expr-function.h
+++ b/lib/filterx/expr-function.h
@@ -29,6 +29,7 @@
 #include "filterx/filterx-expr.h"
 #include "filterx/filterx-object.h"
 #include "filterx/expr-generator.h"
+#include "stats/stats-registry.h"
 #include "generic-number.h"
 #include "plugin.h"
 
diff --git a/lib/filterx/expr-get-subscript.c b/lib/filterx/expr-get-subscript.c
index 6ccee3c26..32a1d51ce 100644
--- a/lib/filterx/expr-get-subscript.c
+++ b/lib/filterx/expr-get-subscript.c
@@ -22,6 +22,8 @@
  */
 #include "filterx/expr-get-subscript.h"
 #include "filterx/filterx-eval.h"
+#include "stats/stats-registry.h"
+#include "stats/stats-cluster-single.h"
 
 typedef struct _FilterXGetSubscript
 {
@@ -117,6 +119,12 @@ _init(FilterXExpr *s, GlobalConfig *cfg)
       return FALSE;
     }
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_get_subscript_evals_total", NULL, 0);
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   return filterx_expr_init_method(s, cfg);
 }
 
@@ -125,6 +133,12 @@ _deinit(FilterXExpr *s, GlobalConfig *cfg)
 {
   FilterXGetSubscript *self = (FilterXGetSubscript *) s;
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_get_subscript_evals_total", NULL, 0);
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   filterx_expr_deinit(self->operand, cfg);
   filterx_expr_deinit(self->key, cfg);
   filterx_expr_deinit_method(s, cfg);
diff --git a/lib/filterx/expr-getattr.c b/lib/filterx/expr-getattr.c
index 781e64cfc..f85bf1585 100644
--- a/lib/filterx/expr-getattr.c
+++ b/lib/filterx/expr-getattr.c
@@ -23,6 +23,8 @@
 #include "filterx/expr-getattr.h"
 #include "filterx/object-string.h"
 #include "filterx/filterx-eval.h"
+#include "stats/stats-registry.h"
+#include "stats/stats-cluster-single.h"
 
 typedef struct _FilterXGetAttr
 {
@@ -98,6 +100,12 @@ _init(FilterXExpr *s, GlobalConfig *cfg)
   if (!filterx_expr_init(self->operand, cfg))
     return FALSE;
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_getattr_evals_total", NULL, 0);
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   return filterx_expr_init_method(s, cfg);
 }
 
@@ -106,6 +114,12 @@ _deinit(FilterXExpr *s, GlobalConfig *cfg)
 {
   FilterXGetAttr *self = (FilterXGetAttr *) s;
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_getattr_evals_total", NULL, 0);
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   filterx_expr_deinit(self->operand, cfg);
   filterx_expr_deinit_method(s, cfg);
 }
diff --git a/lib/filterx/expr-set-subscript.c b/lib/filterx/expr-set-subscript.c
index 341c63c7c..cfb5c100a 100644
--- a/lib/filterx/expr-set-subscript.c
+++ b/lib/filterx/expr-set-subscript.c
@@ -29,6 +29,8 @@
 #include "filterx/object-null.h"
 #include "filterx/object-message-value.h"
 #include "scratch-buffers.h"
+#include "stats/stats-registry.h"
+#include "stats/stats-cluster-single.h"
 
 typedef struct _FilterXSetSubscript
 {
@@ -167,6 +169,12 @@ _init(FilterXExpr *s, GlobalConfig *cfg)
       return FALSE;
     }
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_set_subscript_evals_total", NULL, 0);
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   return filterx_expr_init_method(s, cfg);
 }
 
@@ -175,6 +183,12 @@ _deinit(FilterXExpr *s, GlobalConfig *cfg)
 {
   FilterXSetSubscript *self = (FilterXSetSubscript *) s;
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_set_subscript_evals_total", NULL, 0);
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   filterx_expr_deinit(self->object, cfg);
   filterx_expr_deinit(self->new_value, cfg);
   filterx_expr_deinit(self->key, cfg);
diff --git a/lib/filterx/expr-setattr.c b/lib/filterx/expr-setattr.c
index 274161941..3151a7ed4 100644
--- a/lib/filterx/expr-setattr.c
+++ b/lib/filterx/expr-setattr.c
@@ -30,6 +30,8 @@
 #include "filterx/object-null.h"
 #include "filterx/object-message-value.h"
 #include "scratch-buffers.h"
+#include "stats/stats-registry.h"
+#include "stats/stats-cluster-single.h"
 
 typedef struct _FilterXSetAttr
 {
@@ -143,6 +145,12 @@ _init(FilterXExpr *s, GlobalConfig *cfg)
       return FALSE;
     }
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_setattr_evals_total", NULL, 0);
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   return filterx_expr_init_method(s, cfg);
 }
 
@@ -151,6 +159,12 @@ _deinit(FilterXExpr *s, GlobalConfig *cfg)
 {
   FilterXSetAttr *self = (FilterXSetAttr *) s;
 
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_setattr_evals_total", NULL, 0);
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
   filterx_expr_deinit(self->object, cfg);
   filterx_expr_deinit(self->new_value, cfg);
   filterx_expr_deinit_method(s, cfg);
diff --git a/lib/filterx/expr-template.c b/lib/filterx/expr-template.c
index ea0f57265..f94716ad3 100644
--- a/lib/filterx/expr-template.c
+++ b/lib/filterx/expr-template.c
@@ -25,6 +25,8 @@
 #include "filterx/filterx-eval.h"
 #include "template/templates.h"
 #include "scratch-buffers.h"
+#include "stats/stats-registry.h"
+#include "stats/stats-cluster-single.h"
 
 typedef struct _FilterXTemplate
 {
@@ -63,6 +65,34 @@ _free(FilterXExpr *s)
   filterx_expr_free_method(s);
 }
 
+static gboolean
+_template_init(FilterXExpr *s, GlobalConfig *cfg)
+{
+  FilterXTemplate *self = (FilterXTemplate *) s;
+
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_template_evals_total", NULL, 0);
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
+  return filterx_expr_init_method(s, cfg);
+}
+
+static void
+_template_deinit(FilterXExpr *s, GlobalConfig *cfg)
+{
+  FilterXTemplate *self = (FilterXTemplate *) s;
+
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_template_evals_total", NULL, 0);
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
+  filterx_expr_deinit_method(s, cfg);
+}
+
 /* NOTE: takes the object reference */
 FilterXExpr *
 filterx_template_new(LogTemplate *template)
@@ -70,6 +100,8 @@ filterx_template_new(LogTemplate *template)
   FilterXTemplate *self = g_new0(FilterXTemplate, 1);
 
   filterx_expr_init_instance(&self->super);
+  self->super.init = _template_init;
+  self->super.deinit = _template_deinit;
   self->super.eval = _eval;
   self->super.free_fn = _free;
   self->template = template;
diff --git a/lib/filterx/expr-variable.c b/lib/filterx/expr-variable.c
index fba862149..5ed2e51ff 100644
--- a/lib/filterx/expr-variable.c
+++ b/lib/filterx/expr-variable.c
@@ -27,6 +27,8 @@
 #include "filterx/filterx-eval.h"
 #include "filterx/filterx-variable.h"
 #include "logmsg/logmsg.h"
+#include "stats/stats-registry.h"
+#include "stats/stats-cluster-single.h"
 
 
 typedef struct _FilterXVariableExpr
@@ -173,6 +175,34 @@ _free(FilterXExpr *s)
   filterx_expr_free_method(s);
 }
 
+static gboolean
+_init(FilterXExpr *s, GlobalConfig *cfg)
+{
+  FilterXVariableExpr *self = (FilterXVariableExpr *) s;
+
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_variable_evals_total", NULL, 0);
+  stats_register_counter(STATS_LEVEL3, &sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
+  return filterx_expr_init_method(s, cfg);
+}
+
+static void
+_deinit(FilterXExpr *s, GlobalConfig *cfg)
+{
+  FilterXVariableExpr *self = (FilterXVariableExpr *) s;
+
+  stats_lock();
+  StatsClusterKey sc_key;
+  stats_cluster_single_key_set(&sc_key, "fx_variable_evals_total", NULL, 0);
+  stats_unregister_counter(&sc_key, SC_TYPE_SINGLE_VALUE, &self->super.eval_count);
+  stats_unlock();
+
+  return filterx_expr_deinit_method(s, cfg);
+}
+
 static FilterXExpr *
 filterx_variable_expr_new(FilterXString *name, FilterXVariableType type)
 {
@@ -180,6 +210,8 @@ filterx_variable_expr_new(FilterXString *name, FilterXVariableType type)
 
   filterx_expr_init_instance(&self->super);
   self->super.free_fn = _free;
+  self->super.init = _init;
+  self->super.deinit = _deinit;
   self->super.eval = _eval;
   self->super._update_repr = _update_repr;
   self->super.assign = _assign;