optimize blockstore flush (#614)

* rework block store block flushing to only happen once at end of block write outside of locks
* fix warning at startup if no gc.dlog file exists

1 files changed, 10 insertions, 6 deletions

diff --git a/src/zenstore/include/zenstore/blockstore.h b/src/zenstore/include/zenstore/blockstore.h
index 4006f4275..bc9b5da40 100644
--- a/src/zenstore/include/zenstore/blockstore.h
+++ b/src/zenstore/include/zenstore/blockstore.h
@@ -94,7 +94,7 @@ struct BlockStoreFile : public RefCounted
 	IoBuffer					 GetChunk(uint64_t Offset, uint64_t Size);
 	void						 Read(void* Data, uint64_t Size, uint64_t FileOffset);
 	void						 Write(const void* Data, uint64_t Size, uint64_t FileOffset);
-	void						 Flush(uint64_t FinalSize = (uint64_t)-1);
+	void						 Flush();
 	BasicFile&					 GetBasicFile();
 	void	 StreamByteRange(uint64_t FileOffset, uint64_t Size, std::function<void(const void* Data, uint64_t Size)>&& ChunkFun);
 	bool	 IsOpen() const;
@@ -186,17 +186,21 @@ public:
 	IoBuffer GetMetaData(uint32_t BlockIndex) const;
 
 private:
+	void AddActiveWriteBlock(RwLock::ExclusiveLockScope& Lock, uint32_t BlockIndex);
+	void RemoveActiveWriteBlock(uint32_t BlockIndex);
+
 	static const char*			 GetBlockFileExtension();
 	static std::filesystem::path GetBlockPath(const std::filesystem::path& BlocksBasePath, const uint32_t BlockIndex);
 	uint32_t GetFreeBlockIndex(uint32_t StartProbeIndex, RwLock::ExclusiveLockScope&, std::filesystem::path& OutBlockPath) const;
 
 	tsl::robin_map<uint32_t, Ref<BlockStoreFile>> m_ChunkBlocks;
 
-	mutable RwLock		  m_InsertLock;	 // used to serialize inserts
-	Ref<BlockStoreFile>	  m_WriteBlock;
-	std::uint32_t		  m_CurrentInsertOffset = 0;
-	std::atomic_uint32_t  m_WriteBlockIndex{};
-	std::vector<uint32_t> m_ActiveWriteBlocks;
+	mutable RwLock					 m_InsertLock;	// used to serialize inserts
+	Ref<BlockStoreFile>				 m_WriteBlock;
+	std::uint32_t					 m_CurrentInsertOffset = 0;
+	std::atomic_uint32_t			 m_WriteBlockIndex{};
+	eastl::fixed_vector<uint32_t, 2> m_ActiveWriteBlocks;
+	eastl::fixed_vector<uint32_t, 2> m_BlocksToFlush;
 
 	uint64_t			  m_MaxBlockSize  = 1u << 28;
 	uint64_t			  m_MaxBlockCount = BlockStoreDiskLocation::MaxBlockIndex + 1;