[pull] master from prestodb:master

presto-native-execution/presto_cpp/main/common/Configs.cpp

@@ -248,6 +248,7 @@ SystemConfig::SystemConfig() {
           NUM_PROP(kHttpClientHttp2InitialStreamWindow, 1 << 23 /*8MB*/),
           NUM_PROP(kHttpClientHttp2StreamWindow, 1 << 23 /*8MB*/),
           NUM_PROP(kHttpClientHttp2SessionWindow, 1 << 26 /*64MB*/),
+          BOOL_PROP(kHttpClientConnectionReuseCounterEnabled, true),
           STR_PROP(kExchangeMaxErrorDuration, "3m"),
           STR_PROP(kExchangeRequestTimeout, "20s"),
           STR_PROP(kExchangeConnectTimeout, "20s"),
@@ -952,6 +953,11 @@ uint32_t SystemConfig::httpClientHttp2SessionWindow() const {
   return optionalProperty<uint32_t>(kHttpClientHttp2SessionWindow).value();
 }
 
+bool SystemConfig::httpClientConnectionReuseCounterEnabled() const {
+  return optionalProperty<bool>(kHttpClientConnectionReuseCounterEnabled)
+      .value();
+}
+
 std::chrono::duration<double> SystemConfig::exchangeMaxErrorDuration() const {
   return velox::config::toDuration(
       optionalProperty(kExchangeMaxErrorDuration).value());

presto-native-execution/presto_cpp/main/common/Configs.h

@@ -703,6 +703,11 @@ class SystemConfig : public ConfigBase {
   static constexpr std::string_view kHttpClientHttp2SessionWindow{
       "http-client.http2.session-window"};
 
+  /// Whether to enable HTTP client connection reuse counter reporting.
+  /// When enabled, tracks connection first use and reuse metrics.
+  static constexpr std::string_view kHttpClientConnectionReuseCounterEnabled{
+      "http-client.connection-reuse-counter-enabled"};
+
   static constexpr std::string_view kExchangeMaxErrorDuration{
       "exchange.max-error-duration"};
 
@@ -1153,6 +1158,8 @@ class SystemConfig : public ConfigBase {
 
   uint32_t httpClientHttp2SessionWindow() const;
 
+  bool httpClientConnectionReuseCounterEnabled() const;
+
   std::chrono::duration<double> exchangeMaxErrorDuration() const;
 
   std::chrono::duration<double> exchangeRequestTimeoutMs() const;

presto-native-execution/presto_cpp/main/common/Counters.cpp

@@ -41,6 +41,10 @@ void registerPrestoMetrics() {
       100);
   DEFINE_METRIC(
       kCounterHttpClientNumConnectionsCreated, facebook::velox::StatType::SUM);
+  DEFINE_METRIC(
+      kCounterHttpClientConnectionFirstUse, facebook::velox::StatType::SUM);
+  DEFINE_METRIC(
+      kCounterHttpClientConnectionReuse, facebook::velox::StatType::SUM);
   // Tracks http client transaction create delay in range of [0, 30s] with
   // 30 buckets and reports P50, P90, P99, and P100.
   DEFINE_HISTOGRAM_METRIC(

presto-native-execution/presto_cpp/main/common/Counters.h

@@ -43,6 +43,13 @@ constexpr std::string_view kCounterHTTPRequestSizeBytes{
 
 constexpr std::string_view kCounterHttpClientNumConnectionsCreated{
     "presto_cpp.http.client.num_connections_created"};
+/// Number of HTTP requests that are the first request on a connection
+// (seqNo == 0).
+constexpr std::string_view kCounterHttpClientConnectionFirstUse{
+    "presto_cpp.http.client.connection_first_use"};
+/// Number of HTTP requests sent on reused connections (seqNo > 0).
+constexpr std::string_view kCounterHttpClientConnectionReuse{
+    "presto_cpp.http.client.connection_reuse"};
 constexpr std::string_view kCounterHTTPClientTransactionCreateDelay{
     "presto_cpp.http.client.transaction_create_delay_ms"};
 /// Peak number of bytes queued in PrestoExchangeSource waiting for consume.

presto-native-execution/presto_cpp/main/http/HttpClient.cpp

@@ -214,6 +214,19 @@ class ResponseHandler : public proxygen::HTTPTransactionHandler {
   void setTransaction(proxygen::HTTPTransaction* txn) noexcept override {
     txn_ = CHECK_NOTNULL(txn);
     protocol_ = txn_->getTransport().getCodec().getProtocol();
+    // Track connection usage via sequence number:
+    // - seqNo == 0: First request on this connection
+    // - seqNo > 0: Connection is being reused for subsequent requests
+    // Reuse rate = connection_reuse / (connection_first_use + connection_reuse)
+    if (SystemConfig::instance()->httpClientConnectionReuseCounterEnabled()) {
+      const uint32_t seqNo = txn_->getSequenceNumber();
+      if (seqNo > 0) {
+        RECORD_METRIC_VALUE(kCounterHttpClientConnectionReuse);
+        VLOG(2) << "HttpClient reusing connection, seqNo=" << seqNo;
+      } else {
+        RECORD_METRIC_VALUE(kCounterHttpClientConnectionFirstUse);
+      }
+    }
   }
 
   void detachTransaction() noexcept override {