diff --git a/storage/rocksdb/rocksdb/logging/event_logger.cc b/storage/rocksdb/rocksdb/logging/event_logger.cc
new file mode 100644
index 0000000000000000000000000000000000000000..78bf4f8ff5bf23bbf9adf33dce51f26491165e8b
--- /dev/null
+++ b/storage/rocksdb/rocksdb/logging/event_logger.cc
@@ -0,0 +1,70 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include "logging/event_logger.h"
+
+#include <cassert>
+#include <cinttypes>
+#include <sstream>
+#include <string>
+
+#include "util/string_util.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+EventLoggerStream::EventLoggerStream(Logger* logger)
+    : logger_(logger),
+      log_buffer_(nullptr),
+      max_log_size_(0),
+      json_writer_(nullptr) {}
+
+EventLoggerStream::EventLoggerStream(LogBuffer* log_buffer,
+                                     const size_t max_log_size)
+    : logger_(nullptr),
+      log_buffer_(log_buffer),
+      max_log_size_(max_log_size),
+      json_writer_(nullptr) {}
+
+EventLoggerStream::~EventLoggerStream() {
+  if (json_writer_) {
+    json_writer_->EndObject();
+#ifdef ROCKSDB_PRINT_EVENTS_TO_STDOUT
+    printf("%s\n", json_writer_->Get().c_str());
+#else
+    if (logger_) {
+      EventLogger::Log(logger_, *json_writer_);
+    } else if (log_buffer_) {
+      assert(max_log_size_);
+      EventLogger::LogToBuffer(log_buffer_, *json_writer_, max_log_size_);
+    }
+#endif
+    delete json_writer_;
+  }
+}
+
+void EventLogger::Log(const JSONWriter& jwriter) {
+  Log(logger_, jwriter);
+}
+
+void EventLogger::Log(Logger* logger, const JSONWriter& jwriter) {
+#ifdef ROCKSDB_PRINT_EVENTS_TO_STDOUT
+  printf("%s\n", jwriter.Get().c_str());
+#else
+  ROCKSDB_NAMESPACE::Log(logger, "%s %s", Prefix(), jwriter.Get().c_str());
+#endif
+}
+
+void EventLogger::LogToBuffer(LogBuffer* log_buffer, const JSONWriter& jwriter,
+                              const size_t max_log_size) {
+#ifdef ROCKSDB_PRINT_EVENTS_TO_STDOUT
+  printf("%s\n", jwriter.Get().c_str());
+#else
+  assert(log_buffer);
+  ROCKSDB_NAMESPACE::LogToBuffer(log_buffer, max_log_size, "%s %s", Prefix(),
+                                 jwriter.Get().c_str());
+#endif
+}
+
+}  // namespace ROCKSDB_NAMESPACE
diff --git a/storage/rocksdb/rocksdb/logging/event_logger.h b/storage/rocksdb/rocksdb/logging/event_logger.h
new file mode 100644
index 0000000000000000000000000000000000000000..596eb0f51709fc329203d2985a63bd0e1bc57ec3
--- /dev/null
+++ b/storage/rocksdb/rocksdb/logging/event_logger.h
@@ -0,0 +1,203 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#include <memory>
+#include <sstream>
+#include <string>
+#include <chrono>
+
+#include "logging/log_buffer.h"
+#include "rocksdb/env.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class JSONWriter {
+ public:
+  JSONWriter() : state_(kExpectKey), first_element_(true), in_array_(false) {
+    stream_ << "{";
+  }
+
+  void AddKey(const std::string& key) {
+    assert(state_ == kExpectKey);
+    if (!first_element_) {
+      stream_ << ", ";
+    }
+    stream_ << "\"" << key << "\": ";
+    state_ = kExpectValue;
+    first_element_ = false;
+  }
+
+  void AddValue(const char* value) {
+    assert(state_ == kExpectValue || state_ == kInArray);
+    if (state_ == kInArray && !first_element_) {
+      stream_ << ", ";
+    }
+    stream_ << "\"" << value << "\"";
+    if (state_ != kInArray) {
+      state_ = kExpectKey;
+    }
+    first_element_ = false;
+  }
+
+  template <typename T>
+  void AddValue(const T& value) {
+    assert(state_ == kExpectValue || state_ == kInArray);
+    if (state_ == kInArray && !first_element_) {
+      stream_ << ", ";
+    }
+    stream_ << value;
+    if (state_ != kInArray) {
+      state_ = kExpectKey;
+    }
+    first_element_ = false;
+  }
+
+  void StartArray() {
+    assert(state_ == kExpectValue);
+    state_ = kInArray;
+    in_array_ = true;
+    stream_ << "[";
+    first_element_ = true;
+  }
+
+  void EndArray() {
+    assert(state_ == kInArray);
+    state_ = kExpectKey;
+    in_array_ = false;
+    stream_ << "]";
+    first_element_ = false;
+  }
+
+  void StartObject() {
+    assert(state_ == kExpectValue);
+    state_ = kExpectKey;
+    stream_ << "{";
+    first_element_ = true;
+  }
+
+  void EndObject() {
+    assert(state_ == kExpectKey);
+    stream_ << "}";
+    first_element_ = false;
+  }
+
+  void StartArrayedObject() {
+    assert(state_ == kInArray && in_array_);
+    state_ = kExpectValue;
+    if (!first_element_) {
+      stream_ << ", ";
+    }
+    StartObject();
+  }
+
+  void EndArrayedObject() {
+    assert(in_array_);
+    EndObject();
+    state_ = kInArray;
+  }
+
+  std::string Get() const { return stream_.str(); }
+
+  JSONWriter& operator<<(const char* val) {
+    if (state_ == kExpectKey) {
+      AddKey(val);
+    } else {
+      AddValue(val);
+    }
+    return *this;
+  }
+
+  JSONWriter& operator<<(const std::string& val) {
+    return *this << val.c_str();
+  }
+
+  template <typename T>
+  JSONWriter& operator<<(const T& val) {
+    assert(state_ != kExpectKey);
+    AddValue(val);
+    return *this;
+  }
+
+ private:
+  enum JSONWriterState {
+    kExpectKey,
+    kExpectValue,
+    kInArray,
+    kInArrayedObject,
+  };
+  JSONWriterState state_;
+  bool first_element_;
+  bool in_array_;
+  std::ostringstream stream_;
+};
+
+class EventLoggerStream {
+ public:
+  template <typename T>
+  EventLoggerStream& operator<<(const T& val) {
+    MakeStream();
+    *json_writer_ << val;
+    return *this;
+  }
+
+  void StartArray() { json_writer_->StartArray(); }
+  void EndArray() { json_writer_->EndArray(); }
+  void StartObject() { json_writer_->StartObject(); }
+  void EndObject() { json_writer_->EndObject(); }
+
+  ~EventLoggerStream();
+
+ private:
+  void MakeStream() {
+    if (!json_writer_) {
+      json_writer_ = new JSONWriter();
+      *this << "time_micros"
+            << std::chrono::duration_cast<std::chrono::microseconds>(
+                   std::chrono::system_clock::now().time_since_epoch()).count();
+    }
+  }
+  friend class EventLogger;
+  explicit EventLoggerStream(Logger* logger);
+  explicit EventLoggerStream(LogBuffer* log_buffer, const size_t max_log_size);
+  // exactly one is non-nullptr
+  Logger* const logger_;
+  LogBuffer* const log_buffer_;
+  const size_t max_log_size_;  // used only for log_buffer_
+  // ownership
+  JSONWriter* json_writer_;
+};
+
+// here is an example of the output that will show up in the LOG:
+// 2015/01/15-14:13:25.788019 1105ef000 EVENT_LOG_v1 {"time_micros":
+// 1421360005788015, "event": "table_file_creation", "file_number": 12,
+// "file_size": 1909699}
+class EventLogger {
+ public:
+  static const char* Prefix() {
+    return "EVENT_LOG_v1";
+  }
+
+  explicit EventLogger(Logger* logger) : logger_(logger) {}
+  EventLoggerStream Log() { return EventLoggerStream(logger_); }
+  EventLoggerStream LogToBuffer(LogBuffer* log_buffer) {
+    return EventLoggerStream(log_buffer, LogBuffer::kDefaultMaxLogSize);
+  }
+  EventLoggerStream LogToBuffer(LogBuffer* log_buffer,
+                                const size_t max_log_size) {
+    return EventLoggerStream(log_buffer, max_log_size);
+  }
+  void Log(const JSONWriter& jwriter);
+  static void Log(Logger* logger, const JSONWriter& jwriter);
+  static void LogToBuffer(
+      LogBuffer* log_buffer, const JSONWriter& jwriter,
+      const size_t max_log_size = LogBuffer::kDefaultMaxLogSize);
+
+ private:
+  Logger* logger_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE
diff --git a/storage/rocksdb/rocksdb/logging/event_logger_test.cc b/storage/rocksdb/rocksdb/logging/event_logger_test.cc
new file mode 100644
index 0000000000000000000000000000000000000000..656d73c87b5d68cce770e747f5e4b334ee1788cd
--- /dev/null
+++ b/storage/rocksdb/rocksdb/logging/event_logger_test.cc
@@ -0,0 +1,43 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include <string>
+
+#include "logging/event_logger.h"
+#include "test_util/testharness.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class EventLoggerTest : public testing::Test {};
+
+class StringLogger : public Logger {
+ public:
+  using Logger::Logv;
+  void Logv(const char* format, va_list ap) override {
+    vsnprintf(buffer_, sizeof(buffer_), format, ap);
+  }
+  char* buffer() { return buffer_; }
+
+ private:
+  char buffer_[1000];
+};
+
+TEST_F(EventLoggerTest, SimpleTest) {
+  StringLogger logger;
+  EventLogger event_logger(&logger);
+  event_logger.Log() << "id" << 5 << "event"
+                     << "just_testing";
+  std::string output(logger.buffer());
+  ASSERT_TRUE(output.find("\"event\": \"just_testing\"") != std::string::npos);
+  ASSERT_TRUE(output.find("\"id\": 5") != std::string::npos);
+  ASSERT_TRUE(output.find("\"time_micros\"") != std::string::npos);
+}
+
+}  // namespace ROCKSDB_NAMESPACE
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}