cache reference tracking (#455)

- Feature: Add caching of referenced CId content for structured cache records, this avoid disk thrashing when gathering references for GC
  - disabled by default, enable with `--cache-reference-cache-enabled`
- Improvement: Faster collection of referenced CId content in project store

1 files changed, 5 insertions, 2 deletions

diff --git a/src/zenserver/cache/structuredcachestore.h b/src/zenserver/cache/structuredcachestore.h
index eca2f1880..672858fa0 100644
--- a/src/zenserver/cache/structuredcachestore.h
+++ b/src/zenserver/cache/structuredcachestore.h
@@ -81,11 +81,12 @@ public:
 	ZenCacheNamespace(GcManager&							   Gc,
 					  JobQueue&								   JobQueue,
 					  const std::filesystem::path&			   RootDir,
+					  bool									   EnableReferenceCaching,
 					  const ZenCacheMemoryLayer::Configuration MemLayerConfig = {});
 	~ZenCacheNamespace();
 
 	bool Get(std::string_view Bucket, const IoHash& HashKey, ZenCacheValue& OutValue);
-	void Put(std::string_view Bucket, const IoHash& HashKey, const ZenCacheValue& Value);
+	void Put(std::string_view Bucket, const IoHash& HashKey, const ZenCacheValue& Value, std::span<IoHash> References);
 
 	bool DropBucket(std::string_view Bucket);
 	void EnumerateBucketContents(std::string_view																		 Bucket,
@@ -144,6 +145,7 @@ public:
 	{
 		std::filesystem::path			   BasePath;
 		bool							   AllowAutomaticCreationOfNamespaces = false;
+		bool							   EnableReferenceCaching			  = false;
 		ZenCacheMemoryLayer::Configuration MemLayerConfig;
 		struct LogConfig
 		{
@@ -191,7 +193,8 @@ public:
 			 std::string_view			Namespace,
 			 std::string_view			Bucket,
 			 const IoHash&				HashKey,
-			 const ZenCacheValue&		Value);
+			 const ZenCacheValue&		Value,
+			 std::span<IoHash>			References);
 	bool DropBucket(std::string_view Namespace, std::string_view Bucket);
 	bool DropNamespace(std::string_view Namespace);
 	void Flush();