diff --git a/internal/core/src/exec/operator/FilterBitsNode.cpp b/internal/core/src/exec/operator/FilterBitsNode.cpp
index 14119cf525494..e6cebee7358bf 100644
--- a/internal/core/src/exec/operator/FilterBitsNode.cpp
+++ b/internal/core/src/exec/operator/FilterBitsNode.cpp
@@ -97,6 +97,9 @@ PhyFilterBitsNode::GetOutput() {
     bitset.flip();
     Assert(bitset.size() == need_process_rows_);
     Assert(valid_bitset.size() == need_process_rows_);
+    auto filter_ratio =
+        bitset.size() != 0 ? 1 - float(bitset.count()) / bitset.size() : 0;
+    monitor::internal_core_expr_filter_ratio.Observe(filter_ratio);
     // num_processed_rows_ = need_process_rows_;
     std::vector<VectorPtr> col_res;
     col_res.push_back(std::make_shared<ColumnVector>(std::move(bitset),
diff --git a/internal/core/src/monitor/prometheus_client.cpp b/internal/core/src/monitor/prometheus_client.cpp
index 7ec3dadae203e..1a806cb268f46 100644
--- a/internal/core/src/monitor/prometheus_client.cpp
+++ b/internal/core/src/monitor/prometheus_client.cpp
@@ -212,6 +212,8 @@ std::map<std::string, std::string> randomSampleLatencyLabels{
     {"type", "random_sample_latency"}};
 std::map<std::string, std::string> optimizeExprLatencyLabels{
     {"type", "optimize_expr_latency"}};
+std::map<std::string, std::string> filterRatioLabels{
+    {"type", "expr_filter_ratio"}};
 
 DEFINE_PROMETHEUS_HISTOGRAM_FAMILY(internal_core_search_latency,
                                    "[cpp]latency(us) of search on segment")
@@ -247,6 +249,10 @@ DEFINE_PROMETHEUS_HISTOGRAM(internal_core_search_latency_random_sample,
 DEFINE_PROMETHEUS_HISTOGRAM(internal_core_optimize_expr_latency,
                             internal_core_search_latency,
                             optimizeExprLatencyLabels)
+DEFINE_PROMETHEUS_HISTOGRAM_WITH_BUCKETS(internal_core_expr_filter_ratio,
+                                         internal_core_search_latency,
+                                         filterRatioLabels,
+                                         ratioBuckets)
 // mmap metrics
 std::map<std::string, std::string> mmapAllocatedSpaceAnonLabel = {
     {"type", "anon"}};
diff --git a/internal/core/src/monitor/prometheus_client.h b/internal/core/src/monitor/prometheus_client.h
index 579f9f562e849..f5e63459841b4 100644
--- a/internal/core/src/monitor/prometheus_client.h
+++ b/internal/core/src/monitor/prometheus_client.h
@@ -143,6 +143,7 @@ DECLARE_PROMETHEUS_HISTOGRAM(internal_core_retrieve_get_target_entry_latency);
 DECLARE_PROMETHEUS_HISTOGRAM(internal_core_search_get_target_entry_latency);
 DECLARE_PROMETHEUS_HISTOGRAM(internal_core_search_latency_random_sample);
 DECLARE_PROMETHEUS_HISTOGRAM(internal_core_optimize_expr_latency);
+DECLARE_PROMETHEUS_HISTOGRAM(internal_core_expr_filter_ratio);
 
 // async cgo metrics
 DECLARE_PROMETHEUS_HISTOGRAM_FAMILY(internal_cgo_queue_duration_seconds);