WIP Add cache statistics

olp-cpp-sdk-core/include/olp/core/cache/DefaultCache.h

@@ -149,6 +149,9 @@ class CORE_API DefaultCache : public KeyValueCache {
    */
   bool RemoveKeysWithPrefix(const std::string& prefix) override;
 
+  /// Implements GetStatistics method of KeyValueCache.
+  Statistics GetStatistics() const override;
+
  private:
   std::shared_ptr<DefaultCacheImpl> impl_;
 };

olp-cpp-sdk-core/include/olp/core/cache/KeyValueCache.h

@@ -57,6 +57,22 @@ class CORE_API KeyValueCache {
    */
   using ValueTypePtr = std::shared_ptr<ValueType>;
 
+  /**
+   * @brief The accumulated statistics for the cache.
+   */
+  struct Statistics {
+    /// The number of bytes written to disk cache with Put methods.
+    uint64_t bytes_written;
+    /// The number of bytes read from disk cache with Get methods.
+    uint64_t bytes_read;
+    /// The number of bytes removed from disk cache with Remove method.
+    uint64_t bytes_removed;
+    /// The number of bytes evicted from disk cache.
+    uint64_t bytes_evicted;
+    /// The size of content stored in mutable disk cache.
+    uint64_t data_size;
+  };
+
   virtual ~KeyValueCache() = default;
 
   /**
@@ -121,6 +137,13 @@ class CORE_API KeyValueCache {
    * @return True if the values are removed; false otherwise.
    */
   virtual bool RemoveKeysWithPrefix(const std::string& prefix) = 0;
+
+  /**
+   * @brief Retrieve the accumulated statistics of the cache instance.
+   *
+   * @return Statistics structure.
+   */
+  virtual Statistics GetStatistics() const { return Statistics{}; }
 };
 
 }  // namespace cache

olp-cpp-sdk-core/src/cache/DefaultCache.cpp

@@ -61,5 +61,9 @@ bool DefaultCache::RemoveKeysWithPrefix(const std::string& key) {
   return impl_->RemoveKeysWithPrefix(key);
 }
 
+DefaultCache::Statistics DefaultCache::GetStatistics() const {
+  return impl_->GetStatistics();
+}
+
 }  // namespace cache
 }  // namespace olp

olp-cpp-sdk-core/src/cache/DefaultCacheImpl.cpp

@@ -264,6 +264,7 @@ bool DefaultCacheImpl::Remove(const std::string& key) {
     PurgeDiskItem(key, *mutable_cache_, removed_data_size);
 
     mutable_cache_data_size_ -= removed_data_size;
+    statistics_.bytes_removed += removed_data_size;
   }
 
   return true;
@@ -284,12 +285,21 @@ bool DefaultCacheImpl::RemoveKeysWithPrefix(const std::string& key) {
   if (mutable_cache_) {
     uint64_t removed_data_size = 0;
     auto result = mutable_cache_->RemoveKeysWithPrefix(key, removed_data_size);
+
     mutable_cache_data_size_ -= removed_data_size;
+    statistics_.bytes_removed += removed_data_size;
+
     return result;
   }
   return true;
 }
 
+KeyValueCache::Statistics DefaultCacheImpl::GetStatistics() {
+  std::lock_guard<std::mutex> lock(cache_lock_);
+  statistics_.data_size = mutable_cache_data_size_;
+  return statistics_;
+}
+
 void DefaultCacheImpl::InitializeLru() {
   if (!mutable_cache_) {
     return;
@@ -438,6 +448,9 @@ bool DefaultCacheImpl::PutMutableCache(const std::string& key,
   mutable_cache_data_size_ += added_data_size;
   mutable_cache_data_size_ -= removed_data_size;
 
+  statistics_.bytes_written += added_data_size;
+  statistics_.bytes_evicted += removed_data_size;
+
   if (mutable_cache_lru_) {
     const auto result = mutable_cache_lru_->InsertOrAssign(key, item_size);
     if (result.first == mutable_cache_lru_->end() && !result.second) {
@@ -522,7 +535,9 @@ DefaultCacheImpl::GetFromDiscCache(const std::string& key) {
     if (expiry <= 0) {
       uint64_t removed_data_size = 0u;
       PurgeDiskItem(key, *mutable_cache_, removed_data_size);
+
       mutable_cache_data_size_ -= removed_data_size;
+      statistics_.bytes_evicted += removed_data_size;
 
       RemoveKeyLru(key);
     } else {
@@ -535,6 +550,8 @@ DefaultCacheImpl::GetFromDiscCache(const std::string& key) {
 
       auto result = mutable_cache_->Get(key);
       if (result) {
+        statistics_.bytes_read += result->size();
+
         return std::make_pair(std::move(result.value()), expiry);
       }
     }

olp-cpp-sdk-core/src/cache/DefaultCacheImpl.h

@@ -49,6 +49,8 @@ class DefaultCacheImpl {
 
   bool RemoveKeysWithPrefix(const std::string& key);
 
+  KeyValueCache::Statistics GetStatistics();
+
  protected:
   /// The LRU cache definition using the leveldb keys as key and the value size
   /// as value.
@@ -108,6 +110,8 @@ class DefaultCacheImpl {
   std::unique_ptr<DiskCache> protected_cache_;
   uint64_t mutable_cache_data_size_;
   std::mutex cache_lock_;
+
+  KeyValueCache::Statistics statistics_;
 };
 
 }  // namespace cache