From c6738ce7bbbd6ff6fc0f7db39cda42c6b699c97b Mon Sep 17 00:00:00 2001
From: Furkan Mutlu <furkan68mutlu@gmail.com>
Date: Fri, 8 May 2026 20:47:05 +0300
Subject: [PATCH 1/8] fix: preserve delta start timestamp in fast path

---
 .../sdk/metrics/state/temporal_metric_storage.h           | 2 ++
 sdk/src/metrics/state/temporal_metric_storage.cc          | 8 +++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h b/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
index 007b3c74cd..ef0315f3ee 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
@@ -56,6 +56,8 @@ class TemporalMetricStorage
   // Lock while building metrics
   mutable opentelemetry::common::SpinLockMutex lock_;
   const AggregationConfig *aggregation_config_;
+  opentelemetry::common::SystemTimestamp last_delta_collection_ts_;
+  bool has_last_delta_collection_ts_ = false;
 };
 }  // namespace metrics
 }  // namespace sdk
diff --git a/sdk/src/metrics/state/temporal_metric_storage.cc b/sdk/src/metrics/state/temporal_metric_storage.cc
index 29be34a8ea..2af533750a 100644
--- a/sdk/src/metrics/state/temporal_metric_storage.cc
+++ b/sdk/src/metrics/state/temporal_metric_storage.cc
@@ -54,6 +54,11 @@ bool TemporalMetricStorage::buildMetrics(CollectorHandle *collector,
   // no other reader configured to collect those data.
   if (collectors.size() == 1 && aggregation_temporarily == AggregationTemporality::kDelta)
   {
+    if (!has_last_delta_collection_ts_)
+    {
+      last_delta_collection_ts_     = sdk_start_ts;
+      has_last_delta_collection_ts_ = true;
+    }
     // If no metrics, early return
     if (delta_metrics->Size() == 0)
     {
@@ -63,8 +68,9 @@ bool TemporalMetricStorage::buildMetrics(CollectorHandle *collector,
     MetricData metric_data;
     metric_data.instrument_descriptor   = instrument_descriptor_;
     metric_data.aggregation_temporality = AggregationTemporality::kDelta;
-    metric_data.start_ts                = sdk_start_ts;
+    metric_data.start_ts                = last_delta_collection_ts_;
     metric_data.end_ts                  = collection_ts;
+    last_delta_collection_ts_           = collection_ts;
 
     // Direct conversion of delta metrics to point data
     delta_metrics->GetAllEntries(

From 62446d845e815795e0eed4c4389b74a5522e2522 Mon Sep 17 00:00:00 2001
From: Furkan Mutlu <furkan68mutlu@gmail.com>
Date: Fri, 8 May 2026 21:17:28 +0300
Subject: [PATCH 2/8] fix: keep tracer alive for ETW spans

---
 .../opentelemetry/exporters/etw/etw_tracer.h  | 41 ++++++++++---------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
index 2b975e239c..35e5ddfde2 100644
--- a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
+++ b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
@@ -64,12 +64,12 @@ class Span;
  * @return              Span instance
  */
 template <class SpanType, class TracerType>
-SpanType *new_span(TracerType *objPtr,
+SpanType *new_span(nostd::shared_ptr<TracerType> objPtr,
                    nostd::string_view name,
                    const opentelemetry::trace::StartSpanOptions &options,
                    std::unique_ptr<opentelemetry::trace::SpanContext> spanContext)
 {
-  return new (std::nothrow) SpanType{*objPtr, name, options, std::move(spanContext)};
+  return new (std::nothrow) SpanType{std::move(objPtr), name, options, std::move(spanContext)};
 }
 
 /**
@@ -159,8 +159,7 @@ void UpdateStatus(T &t, Properties &props)
 /**
  * @brief Tracer class that allows to send spans to ETW Provider.
  */
-class Tracer : public opentelemetry::trace::Tracer,
-               public std::enable_shared_from_this<opentelemetry::trace::Tracer>
+class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_from_this<Tracer>
 {
 public:
   /**
@@ -530,7 +529,9 @@ class Tracer : public opentelemetry::trace::Tracer,
 
     // This template pattern allows us to forward-declare the etw::Span,
     // create an instance of it, then assign it to tracer::Span result.
-    auto currentSpan = new_span<Span, Tracer>(this, name, options, std::move(spanContext));
+    auto owner_ptr = nostd::shared_ptr<Tracer>(this->shared_from_this());
+    auto currentSpan = new_span<Span, Tracer>(std::move(owner_ptr), name, options,
+                                              std::move(spanContext));
     nostd::shared_ptr<opentelemetry::trace::Span> result = to_span_ptr<Span>(currentSpan);
 
     // Decorate with additional standard fields
@@ -783,7 +784,7 @@ class Span : public opentelemetry::trace::Span
   /**
    * @brief Owner Tracer of this Span
    */
-  Tracer &owner_;
+   nostd::shared_ptr<Tracer> owner_;
 
   /**
    * @brief Span name.
@@ -862,14 +863,14 @@ class Span : public opentelemetry::trace::Span
    * @param parent Parent Span (optional)
    * @return
    */
-  Span(Tracer &owner,
-       nostd::string_view name,
-       const opentelemetry::trace::StartSpanOptions &options,
-       std::unique_ptr<opentelemetry::trace::SpanContext> spanContext,
-       Span *parent = nullptr) noexcept
+   Span(nostd::shared_ptr<Tracer> owner,
+        nostd::string_view name,
+        const opentelemetry::trace::StartSpanOptions &options,
+        std::unique_ptr<opentelemetry::trace::SpanContext> spanContext,
+        Span *parent = nullptr) noexcept
       : opentelemetry::trace::Span(),
         start_time_(std::chrono::system_clock::now()),
-        owner_(owner),
+        owner_(std::move(owner)),
         context_(std::move(spanContext)),
         parent_(parent)
   {
@@ -887,7 +888,7 @@ class Span : public opentelemetry::trace::Span
    * @param name Event name.
    * @return
    */
-  void AddEvent(nostd::string_view name) noexcept override { owner_.AddEvent(*this, name); }
+  void AddEvent(nostd::string_view name) noexcept override { owner_->AddEvent(*this, name); }
 
   /**
    * @brief Add named event with custom timestamp.
@@ -898,7 +899,7 @@ class Span : public opentelemetry::trace::Span
   void AddEvent(nostd::string_view name,
                 opentelemetry::common::SystemTimestamp timestamp) noexcept override
   {
-    owner_.AddEvent(*this, name, timestamp);
+    owner_->AddEvent(*this, name, timestamp);
   }
 
   /**
@@ -912,7 +913,7 @@ class Span : public opentelemetry::trace::Span
                 opentelemetry::common::SystemTimestamp timestamp,
                 const opentelemetry::common::KeyValueIterable &attributes) noexcept override
   {
-    owner_.AddEvent(*this, name, timestamp, attributes);
+    owner_->AddEvent(*this, name, timestamp, attributes);
   }
 
 #if OPENTELEMETRY_ABI_VERSION_NO >= 2
@@ -1024,7 +1025,7 @@ class Span : public opentelemetry::trace::Span
 
     if (!has_ended_.exchange(true))
     {
-      owner_.EndSpan(*this, parent_, options);
+      owner_->EndSpan(*this, parent_, options);
     }
   }
 
@@ -1056,7 +1057,7 @@ class Span : public opentelemetry::trace::Span
   /// Get Owner tracer of this Span
   /// </summary>
   /// <returns></returns>
-  opentelemetry::trace::Tracer &tracer() const noexcept { return this->owner_; }
+  opentelemetry::trace::Tracer &tracer() const noexcept { return *this->owner_; }
 };
 
 /**
@@ -1177,9 +1178,9 @@ class TracerProvider : public opentelemetry::trace::TracerProvider
     UNREFERENCED_PARAMETER(args);
     UNREFERENCED_PARAMETER(schema_url);
     ETWProvider::EventFormat evtFmt = config_.encoding;
-    std::shared_ptr<opentelemetry::trace::Tracer> tracer{new (std::nothrow)
-                                                             Tracer(*this, name, evtFmt)};
-    return nostd::shared_ptr<opentelemetry::trace::Tracer>{tracer};
+    std::shared_ptr<Tracer> tracer{new (std::nothrow) Tracer(*this, name, evtFmt)};
+    return nostd::shared_ptr<opentelemetry::trace::Tracer>{
+        std::static_pointer_cast<opentelemetry::trace::Tracer>(tracer)};
   }
 };
 

From 005d87d8910051e196097a6e176266037d087ba5 Mon Sep 17 00:00:00 2001
From: Furkan Mutlu <furkan68mutlu@gmail.com>
Date: Fri, 8 May 2026 21:26:31 +0300
Subject: [PATCH 3/8] chore: remove unrelated metrics changes

---
 .../sdk/metrics/state/temporal_metric_storage.h           | 2 --
 sdk/src/metrics/state/temporal_metric_storage.cc          | 8 +-------
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h b/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
index ef0315f3ee..007b3c74cd 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
@@ -56,8 +56,6 @@ class TemporalMetricStorage
   // Lock while building metrics
   mutable opentelemetry::common::SpinLockMutex lock_;
   const AggregationConfig *aggregation_config_;
-  opentelemetry::common::SystemTimestamp last_delta_collection_ts_;
-  bool has_last_delta_collection_ts_ = false;
 };
 }  // namespace metrics
 }  // namespace sdk
diff --git a/sdk/src/metrics/state/temporal_metric_storage.cc b/sdk/src/metrics/state/temporal_metric_storage.cc
index 2af533750a..29be34a8ea 100644
--- a/sdk/src/metrics/state/temporal_metric_storage.cc
+++ b/sdk/src/metrics/state/temporal_metric_storage.cc
@@ -54,11 +54,6 @@ bool TemporalMetricStorage::buildMetrics(CollectorHandle *collector,
   // no other reader configured to collect those data.
   if (collectors.size() == 1 && aggregation_temporarily == AggregationTemporality::kDelta)
   {
-    if (!has_last_delta_collection_ts_)
-    {
-      last_delta_collection_ts_     = sdk_start_ts;
-      has_last_delta_collection_ts_ = true;
-    }
     // If no metrics, early return
     if (delta_metrics->Size() == 0)
     {
@@ -68,9 +63,8 @@ bool TemporalMetricStorage::buildMetrics(CollectorHandle *collector,
     MetricData metric_data;
     metric_data.instrument_descriptor   = instrument_descriptor_;
     metric_data.aggregation_temporality = AggregationTemporality::kDelta;
-    metric_data.start_ts                = last_delta_collection_ts_;
+    metric_data.start_ts                = sdk_start_ts;
     metric_data.end_ts                  = collection_ts;
-    last_delta_collection_ts_           = collection_ts;
 
     // Direct conversion of delta metrics to point data
     delta_metrics->GetAllEntries(

From 3bc2469337645cb65b02f0e0ad5367a1bfe8c25f Mon Sep 17 00:00:00 2001
From: Furkan Mutlu <furkan68mutlu@gmail.com>
Date: Mon, 11 May 2026 12:47:32 +0300
Subject: [PATCH 4/8] chore: format etw tracer header

---
 .../opentelemetry/exporters/etw/etw_tracer.h  | 51 +++++++++++++------
 1 file changed, 36 insertions(+), 15 deletions(-)

diff --git a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
index 35e5ddfde2..a1d8df8749 100644
--- a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
+++ b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
@@ -397,7 +397,10 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
     }
   }
 
-  const opentelemetry::trace::TraceId &trace_id() { return traceId_; }
+  const opentelemetry::trace::TraceId &trace_id()
+  {
+    return traceId_;
+  }
 
   friend class Span;
 
@@ -530,8 +533,8 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
     // This template pattern allows us to forward-declare the etw::Span,
     // create an instance of it, then assign it to tracer::Span result.
     auto owner_ptr = nostd::shared_ptr<Tracer>(this->shared_from_this());
-    auto currentSpan = new_span<Span, Tracer>(std::move(owner_ptr), name, options,
-                                              std::move(spanContext));
+    auto currentSpan =
+        new_span<Span, Tracer>(std::move(owner_ptr), name, options, std::move(spanContext));
     nostd::shared_ptr<opentelemetry::trace::Span> result = to_span_ptr<Span>(currentSpan);
 
     // Decorate with additional standard fields
@@ -597,7 +600,10 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
    *
    * @since ABI_VERSION 2
    */
-  virtual bool Enabled() const noexcept { return true; }
+  virtual bool Enabled() const noexcept
+  {
+    return true;
+  }
 #endif
 
 #if OPENTELEMETRY_ABI_VERSION_NO == 1
@@ -784,7 +790,7 @@ class Span : public opentelemetry::trace::Span
   /**
    * @brief Owner Tracer of this Span
    */
-   nostd::shared_ptr<Tracer> owner_;
+  nostd::shared_ptr<Tracer> owner_;
 
   /**
    * @brief Span name.
@@ -863,11 +869,11 @@ class Span : public opentelemetry::trace::Span
    * @param parent Parent Span (optional)
    * @return
    */
-   Span(nostd::shared_ptr<Tracer> owner,
-        nostd::string_view name,
-        const opentelemetry::trace::StartSpanOptions &options,
-        std::unique_ptr<opentelemetry::trace::SpanContext> spanContext,
-        Span *parent = nullptr) noexcept
+  Span(nostd::shared_ptr<Tracer> owner,
+       nostd::string_view name,
+       const opentelemetry::trace::StartSpanOptions &options,
+       std::unique_ptr<opentelemetry::trace::SpanContext> spanContext,
+       Span *parent = nullptr) noexcept
       : opentelemetry::trace::Span(),
         start_time_(std::chrono::system_clock::now()),
         owner_(std::move(owner)),
@@ -957,9 +963,15 @@ class Span : public opentelemetry::trace::Span
     status_description_ = description.data();
   }
 
-  opentelemetry::trace::StatusCode GetStatus() { return status_code_; }
+  opentelemetry::trace::StatusCode GetStatus()
+  {
+    return status_code_;
+  }
 
-  void SetAttributes(Properties attributes) { attributes_ = attributes; }
+  void SetAttributes(Properties attributes)
+  {
+    attributes_ = attributes;
+  }
 
   /**
    * @brief Obtain span attributes specified at Span start.
@@ -967,7 +979,10 @@ class Span : public opentelemetry::trace::Span
    *
    * @return ref to Properties collection
    */
-  Properties &GetAttributes() { return attributes_; }
+  Properties &GetAttributes()
+  {
+    return attributes_;
+  }
 
   /**
    * @brief Sets an attribute on the Span. If the Span previously contained a mapping
@@ -1033,7 +1048,10 @@ class Span : public opentelemetry::trace::Span
    * @brief Obtain SpanContext
    * @return
    */
-  opentelemetry::trace::SpanContext GetContext() const noexcept override { return *context_.get(); }
+  opentelemetry::trace::SpanContext GetContext() const noexcept override
+  {
+    return *context_.get();
+  }
 
   /**
    * @brief Check if Span is recording data.
@@ -1057,7 +1075,10 @@ class Span : public opentelemetry::trace::Span
   /// Get Owner tracer of this Span
   /// </summary>
   /// <returns></returns>
-  opentelemetry::trace::Tracer &tracer() const noexcept { return *this->owner_; }
+  opentelemetry::trace::Tracer &tracer() const noexcept
+  {
+    return *this->owner_;
+  }
 };
 
 /**

From add9b1e0514a0ecfd81b4b2ba7640a43dbf32ec8 Mon Sep 17 00:00:00 2001
From: Furkan Mutlu <furkan68mutlu@gmail.com>
Date: Mon, 11 May 2026 22:25:57 +0300
Subject: [PATCH 5/8] chore: fix format errors

---
 .../opentelemetry/exporters/etw/etw_tracer.h  | 35 ++++---------------
 1 file changed, 7 insertions(+), 28 deletions(-)

diff --git a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
index a1d8df8749..4d2fb1f164 100644
--- a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
+++ b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
@@ -397,10 +397,7 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
     }
   }
 
-  const opentelemetry::trace::TraceId &trace_id()
-  {
-    return traceId_;
-  }
+  const opentelemetry::trace::TraceId &trace_id(){return traceId_;}
 
   friend class Span;
 
@@ -600,10 +597,7 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
    *
    * @since ABI_VERSION 2
    */
-  virtual bool Enabled() const noexcept
-  {
-    return true;
-  }
+  virtual bool Enabled() const noexcept{return true;}
 #endif
 
 #if OPENTELEMETRY_ABI_VERSION_NO == 1
@@ -963,15 +957,9 @@ class Span : public opentelemetry::trace::Span
     status_description_ = description.data();
   }
 
-  opentelemetry::trace::StatusCode GetStatus()
-  {
-    return status_code_;
-  }
+  opentelemetry::trace::StatusCode GetStatus(){return status_code_;}
 
-  void SetAttributes(Properties attributes)
-  {
-    attributes_ = attributes;
-  }
+  void SetAttributes(Properties attributes){attributes_ = attributes;}
 
   /**
    * @brief Obtain span attributes specified at Span start.
@@ -979,10 +967,7 @@ class Span : public opentelemetry::trace::Span
    *
    * @return ref to Properties collection
    */
-  Properties &GetAttributes()
-  {
-    return attributes_;
-  }
+  Properties &GetAttributes(){return attributes_;}
 
   /**
    * @brief Sets an attribute on the Span. If the Span previously contained a mapping
@@ -1048,10 +1033,7 @@ class Span : public opentelemetry::trace::Span
    * @brief Obtain SpanContext
    * @return
    */
-  opentelemetry::trace::SpanContext GetContext() const noexcept override
-  {
-    return *context_.get();
-  }
+  opentelemetry::trace::SpanContext GetContext() const noexcept override { return *context_.get(); }
 
   /**
    * @brief Check if Span is recording data.
@@ -1075,10 +1057,7 @@ class Span : public opentelemetry::trace::Span
   /// Get Owner tracer of this Span
   /// </summary>
   /// <returns></returns>
-  opentelemetry::trace::Tracer &tracer() const noexcept
-  {
-    return *this->owner_;
-  }
+  opentelemetry::trace::Tracer &tracer() const noexcept{return *this->owner_;}
 };
 
 /**

From 1f76b52c781364b4ba33c5995832ad9cc3a35f35 Mon Sep 17 00:00:00 2001
From: Furkan Mutlu <furkan68mutlu@gmail.com>
Date: Mon, 11 May 2026 23:33:01 +0300
Subject: [PATCH 6/8] chore: fix format errors

---
 .../include/opentelemetry/exporters/etw/etw_tracer.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
index 4d2fb1f164..cfebd24c02 100644
--- a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
+++ b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
@@ -397,7 +397,7 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
     }
   }
 
-  const opentelemetry::trace::TraceId &trace_id(){return traceId_;}
+  const opentelemetry::trace::TraceId &trace_id() { return traceId_; }
 
   friend class Span;
 
@@ -597,7 +597,7 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
    *
    * @since ABI_VERSION 2
    */
-  virtual bool Enabled() const noexcept{return true;}
+  virtual bool Enabled() const noexcept { return true; }
 #endif
 
 #if OPENTELEMETRY_ABI_VERSION_NO == 1
@@ -957,9 +957,9 @@ class Span : public opentelemetry::trace::Span
     status_description_ = description.data();
   }
 
-  opentelemetry::trace::StatusCode GetStatus(){return status_code_;}
+  opentelemetry::trace::StatusCode GetStatus() { return status_code_; }
 
-  void SetAttributes(Properties attributes){attributes_ = attributes;}
+  void SetAttributes(Properties attributes) { attributes_ = attributes; }
 
   /**
    * @brief Obtain span attributes specified at Span start.
@@ -967,7 +967,7 @@ class Span : public opentelemetry::trace::Span
    *
    * @return ref to Properties collection
    */
-  Properties &GetAttributes(){return attributes_;}
+  Properties &GetAttributes() { return attributes_; }
 
   /**
    * @brief Sets an attribute on the Span. If the Span previously contained a mapping
@@ -1057,7 +1057,7 @@ class Span : public opentelemetry::trace::Span
   /// Get Owner tracer of this Span
   /// </summary>
   /// <returns></returns>
-  opentelemetry::trace::Tracer &tracer() const noexcept{return *this->owner_;}
+  opentelemetry::trace::Tracer &tracer() const noexcept { return *this->owner_; }
 };
 
 /**

From 7ac1f13a5110ae6b60add7fea0f4f7d5483d74f0 Mon Sep 17 00:00:00 2001
From: Furkan Mutlu <furkan68mutlu@gmail.com>
Date: Tue, 26 May 2026 18:19:54 +0300
Subject: [PATCH 7/8] fix: cache ETW tracers in provider

---
 exporters/etw/README.md                       |   8 ++
 .../opentelemetry/exporters/etw/etw_tracer.h  | 126 +++++++++++++++---
 exporters/etw/test/etw_tracer_test.cc         |  15 ++-
 3 files changed, 130 insertions(+), 19 deletions(-)

diff --git a/exporters/etw/README.md b/exporters/etw/README.md
index 372aa5738e..32e99158bd 100644
--- a/exporters/etw/README.md
+++ b/exporters/etw/README.md
@@ -12,5 +12,13 @@ subsequent data recording or forwarding to alternate pipelines and flows.
 Windows Event Tracing infrastructure is available to any vendor or application
 being deployed on Windows.
 
+## Tracer lifetime and reuse
+
+For ETW, the tracer name maps to the ETW provider name/GUID. Applications
+should create one tracer per provider name (and encoding) and reuse it for the
+process or component lifetime. `TracerProvider::GetTracer()` may cache tracers
+internally, so avoid calling `GetTracer()->StartSpan()` in hot paths. Instead,
+obtain the tracer once during setup and reuse it for span creation.
+
 It is recommended to consume this exporter via
 [vcpkg](https://vcpkg.io/en/package/opentelemetry-cpp).
diff --git a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
index cfebd24c02..9d9edb522e 100644
--- a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
+++ b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
@@ -6,6 +6,7 @@
 #include <algorithm>
 #include <atomic>
 
+#include <cctype>
 #include <cstdint>
 #include <cstdio>
 #include <cstdlib>
@@ -16,6 +17,7 @@
 #include <map>
 #include <memory>
 #include <mutex>
+#include <unordered_map>
 #include <sstream>
 #include <vector>
 
@@ -64,12 +66,12 @@ class Span;
  * @return              Span instance
  */
 template <class SpanType, class TracerType>
-SpanType *new_span(nostd::shared_ptr<TracerType> objPtr,
+SpanType *new_span(TracerType *objPtr,
                    nostd::string_view name,
                    const opentelemetry::trace::StartSpanOptions &options,
                    std::unique_ptr<opentelemetry::trace::SpanContext> spanContext)
 {
-  return new (std::nothrow) SpanType{std::move(objPtr), name, options, std::move(spanContext)};
+  return new (std::nothrow) SpanType{*objPtr, name, options, std::move(spanContext)};
 }
 
 /**
@@ -159,7 +161,7 @@ void UpdateStatus(T &t, Properties &props)
 /**
  * @brief Tracer class that allows to send spans to ETW Provider.
  */
-class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_from_this<Tracer>
+class Tracer : public opentelemetry::trace::Tracer
 {
 public:
   /**
@@ -509,7 +511,7 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
     {
       auto noopSpan = nostd::shared_ptr<opentelemetry::trace::Span>{
           new (std::nothrow)
-              opentelemetry::trace::NoopSpan(this->shared_from_this(), std::move(spanContext))};
+              opentelemetry::trace::NoopSpan(std::shared_ptr<Tracer>{}, std::move(spanContext))};
       return noopSpan;
     }
 
@@ -529,9 +531,7 @@ class Tracer : public opentelemetry::trace::Tracer, public std::enable_shared_fr
 
     // This template pattern allows us to forward-declare the etw::Span,
     // create an instance of it, then assign it to tracer::Span result.
-    auto owner_ptr = nostd::shared_ptr<Tracer>(this->shared_from_this());
-    auto currentSpan =
-        new_span<Span, Tracer>(std::move(owner_ptr), name, options, std::move(spanContext));
+    auto currentSpan = new_span<Span, Tracer>(this, name, options, std::move(spanContext));
     nostd::shared_ptr<opentelemetry::trace::Span> result = to_span_ptr<Span>(currentSpan);
 
     // Decorate with additional standard fields
@@ -784,7 +784,7 @@ class Span : public opentelemetry::trace::Span
   /**
    * @brief Owner Tracer of this Span
    */
-  nostd::shared_ptr<Tracer> owner_;
+  Tracer &owner_;
 
   /**
    * @brief Span name.
@@ -863,14 +863,14 @@ class Span : public opentelemetry::trace::Span
    * @param parent Parent Span (optional)
    * @return
    */
-  Span(nostd::shared_ptr<Tracer> owner,
+  Span(Tracer &owner,
        nostd::string_view name,
        const opentelemetry::trace::StartSpanOptions &options,
        std::unique_ptr<opentelemetry::trace::SpanContext> spanContext,
        Span *parent = nullptr) noexcept
       : opentelemetry::trace::Span(),
         start_time_(std::chrono::system_clock::now()),
-        owner_(std::move(owner)),
+        owner_(owner),
         context_(std::move(spanContext)),
         parent_(parent)
   {
@@ -888,7 +888,7 @@ class Span : public opentelemetry::trace::Span
    * @param name Event name.
    * @return
    */
-  void AddEvent(nostd::string_view name) noexcept override { owner_->AddEvent(*this, name); }
+  void AddEvent(nostd::string_view name) noexcept override { owner_.AddEvent(*this, name); }
 
   /**
    * @brief Add named event with custom timestamp.
@@ -899,7 +899,7 @@ class Span : public opentelemetry::trace::Span
   void AddEvent(nostd::string_view name,
                 opentelemetry::common::SystemTimestamp timestamp) noexcept override
   {
-    owner_->AddEvent(*this, name, timestamp);
+    owner_.AddEvent(*this, name, timestamp);
   }
 
   /**
@@ -913,7 +913,7 @@ class Span : public opentelemetry::trace::Span
                 opentelemetry::common::SystemTimestamp timestamp,
                 const opentelemetry::common::KeyValueIterable &attributes) noexcept override
   {
-    owner_->AddEvent(*this, name, timestamp, attributes);
+    owner_.AddEvent(*this, name, timestamp, attributes);
   }
 
 #if OPENTELEMETRY_ABI_VERSION_NO >= 2
@@ -1025,7 +1025,7 @@ class Span : public opentelemetry::trace::Span
 
     if (!has_ended_.exchange(true))
     {
-      owner_->EndSpan(*this, parent_, options);
+      owner_.EndSpan(*this, parent_, options);
     }
   }
 
@@ -1057,9 +1057,58 @@ class Span : public opentelemetry::trace::Span
   /// Get Owner tracer of this Span
   /// </summary>
   /// <returns></returns>
-  opentelemetry::trace::Tracer &tracer() const noexcept { return *this->owner_; }
+  opentelemetry::trace::Tracer &tracer() const noexcept { return this->owner_; }
 };
 
+static inline std::string TrimWhitespace(std::string input)
+{
+  auto is_space = [](unsigned char c) { return std::isspace(c) != 0; };
+  auto begin    = std::find_if_not(input.begin(), input.end(), is_space);
+  if (begin == input.end())
+  {
+    return std::string{};
+  }
+  auto end = std::find_if_not(input.rbegin(), input.rend(), is_space).base();
+  return std::string(begin, end);
+}
+
+static inline ETWProvider::EventFormat ParseEncodingArg(nostd::string_view args,
+                                                        ETWProvider::EventFormat fallback)
+{
+  if (args.size() == 0)
+  {
+    return fallback;
+  }
+
+  std::string arg(args.data(), args.size());
+  arg = TrimWhitespace(std::move(arg));
+  if (arg.empty())
+  {
+    return fallback;
+  }
+
+  std::transform(arg.begin(), arg.end(), arg.begin(), [](unsigned char c) {
+    return static_cast<char>(std::toupper(c));
+  });
+
+  if (arg == "MSGPACK" || arg == "MESSAGEPACK")
+  {
+    return ETWProvider::EventFormat::ETW_MSGPACK;
+  }
+
+  if (arg == "XML")
+  {
+    return ETWProvider::EventFormat::ETW_XML;
+  }
+
+  if (arg == "ETW" || arg == "TLD")
+  {
+    return ETWProvider::EventFormat::ETW_MANIFEST;
+  }
+
+  return fallback;
+}
+
 /**
  * @brief ETW TracerProvider
  */
@@ -1175,13 +1224,56 @@ class TracerProvider : public opentelemetry::trace::TracerProvider
 #endif
       ) noexcept override
   {
-    UNREFERENCED_PARAMETER(args);
     UNREFERENCED_PARAMETER(schema_url);
-    ETWProvider::EventFormat evtFmt = config_.encoding;
+    ETWProvider::EventFormat evtFmt = ParseEncodingArg(args, config_.encoding);
+    TracerCacheKey key{name.data(), name.size(), evtFmt};
+
+    std::lock_guard<std::mutex> lock(tracers_mu_);
+    auto it = tracers_.find(key);
+    if (it != tracers_.end())
+    {
+      return nostd::shared_ptr<opentelemetry::trace::Tracer>{
+          std::static_pointer_cast<opentelemetry::trace::Tracer>(it->second)};
+    }
+
     std::shared_ptr<Tracer> tracer{new (std::nothrow) Tracer(*this, name, evtFmt)};
+    tracers_.emplace(std::move(key), tracer);
     return nostd::shared_ptr<opentelemetry::trace::Tracer>{
         std::static_pointer_cast<opentelemetry::trace::Tracer>(tracer)};
   }
+
+private:
+  struct TracerCacheKey
+  {
+    std::string name;
+    ETWProvider::EventFormat encoding;
+
+    TracerCacheKey(std::string value, ETWProvider::EventFormat format)
+        : name(std::move(value)), encoding(format)
+    {}
+
+    TracerCacheKey(const char *value, size_t size, ETWProvider::EventFormat format)
+        : name(value, size), encoding(format)
+    {}
+
+    bool operator==(const TracerCacheKey &other) const
+    {
+      return encoding == other.encoding && name == other.name;
+    }
+  };
+
+  struct TracerCacheKeyHash
+  {
+    size_t operator()(const TracerCacheKey &key) const noexcept
+    {
+      size_t name_hash = std::hash<std::string>{}(key.name);
+      size_t fmt_hash  = static_cast<size_t>(key.encoding);
+      return name_hash ^ (fmt_hash + 0x9e3779b97f4a7c15ULL + (name_hash << 6) + (name_hash >> 2));
+    }
+  };
+
+  std::mutex tracers_mu_;
+  std::unordered_map<TracerCacheKey, std::shared_ptr<Tracer>, TracerCacheKeyHash> tracers_;
 };
 
 }  // namespace etw
diff --git a/exporters/etw/test/etw_tracer_test.cc b/exporters/etw/test/etw_tracer_test.cc
index 7d32a2ffba..07ba575349 100644
--- a/exporters/etw/test/etw_tracer_test.cc
+++ b/exporters/etw/test/etw_tracer_test.cc
@@ -392,7 +392,7 @@ TEST(ETWTracer, GlobalSingletonTracer)
 }
 */
 
-  // Obtain a different tracer withs its own trace-id.
+  // Obtain the same tracer instance with the same trace-id as before.
   auto localTracer = GetGlobalTracerProvider().GetTracer(kGlobalProviderName);
   auto s2 = localTracer->StartSpan("Span2");
   auto traceId2 = s2->GetContext().trace_id();
@@ -455,7 +455,7 @@ TEST(ETWTracer, GlobalSingletonTracer)
   }
 }
 */
-  EXPECT_NE(traceId1, traceId2);
+  EXPECT_EQ(traceId1, traceId2);
   EXPECT_EQ(traceId1, traceId3);
 
 #  if OPENTELEMETRY_ABI_VERSION_NO == 1
@@ -503,6 +503,17 @@ TEST(ETWTracer, AlwayOffTailSampler)
   auto tracer = tp.GetTracer(providerName);
 }
 
+TEST(ETWTracer, SpanSurvivesTracerReassignment)
+{
+  exporter::etw::TracerProvider tp;
+  auto tracer = tp.GetTracer("Geneva-Tracer-Foo");
+  auto spanFoo = tracer->StartSpan("Span-Foo");
+  tracer = tp.GetTracer("Geneva-Tracer-Bar");
+  auto spanBar = tracer->StartSpan("Span-Bar");
+  EXPECT_NO_THROW(spanFoo->End());
+  EXPECT_NO_THROW(spanBar->End());
+}
+
 TEST(ETWTracer, CustomIdGenerator)
 {
   std::string providerName = kGlobalProviderName; // supply unique instrumentation name here

From b8313f6a0f8539223e7809fbffcc09de18262b51 Mon Sep 17 00:00:00 2001
From: Furkan Mutlu <furkan68mutlu@gmail.com>
Date: Wed, 27 May 2026 15:56:34 +0300
Subject: [PATCH 8/8] fix: stabilize ETW tracer cache shutdown

---
 .../opentelemetry/exporters/etw/etw_tracer.h        | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
index 9d9edb522e..9f2cb1f980 100644
--- a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
+++ b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
@@ -17,8 +17,8 @@
 #include <map>
 #include <memory>
 #include <mutex>
-#include <unordered_map>
 #include <sstream>
+#include <unordered_map>
 #include <vector>
 
 #include "opentelemetry/nostd/shared_ptr.h"
@@ -170,6 +170,8 @@ class Tracer : public opentelemetry::trace::Tracer
   bool IsClosed() const noexcept { return isClosed_.load(); }
 
 private:
+  friend class TracerProvider;
+
   /**
    * @brief Parent provider of this Tracer
    */
@@ -1087,9 +1089,8 @@ static inline ETWProvider::EventFormat ParseEncodingArg(nostd::string_view args,
     return fallback;
   }
 
-  std::transform(arg.begin(), arg.end(), arg.begin(), [](unsigned char c) {
-    return static_cast<char>(std::toupper(c));
-  });
+  std::transform(arg.begin(), arg.end(), arg.begin(),
+                 [](unsigned char c) { return static_cast<char>(std::toupper(c)); });
 
   if (arg == "MSGPACK" || arg == "MESSAGEPACK")
   {
@@ -1156,6 +1157,8 @@ class TracerProvider : public opentelemetry::trace::TracerProvider
         id_generator_{std::move(id_generator)},
         tail_sampler_{std::move(tail_sampler)}
   {
+    (void)Tracer::etwProvider().is_registered(std::string{});
+
     // By default we ensure that all events carry their with TraceId and SpanId
     GetOption(options, "enableTraceId", config_.enableTraceId, true);
     GetOption(options, "enableSpanId", config_.enableSpanId, true);
@@ -1193,6 +1196,8 @@ class TracerProvider : public opentelemetry::trace::TracerProvider
         tail_sampler_{
             std::unique_ptr<opentelemetry::exporter::etw::TailSampler>(new AlwaysOnTailSampler())}
   {
+    (void)Tracer::etwProvider().is_registered(std::string{});
+
     config_.enableTraceId           = true;
     config_.enableSpanId            = true;
     config_.enableActivityId        = false;