faster accesstime save restore (#439)

- Improvement: Reduce time a cache bucket is locked for write when flushing/garbage collecting
  - Change format for faster read/write and reduced size on disk
  - Don't lock index while writing manifest to disk
  - Skip garbage collect if we are currently in a Flush operation
  - BlockStore::Flush no longer terminates currently writing block
  - Garbage collect references to currently writing block but keep the block as new data may be added
  - Fix BlockStore::Prune used disk space calculation
  - Don't materialize data in filecas when we just need the size

1 files changed, 43 insertions, 23 deletions

diff --git a/src/zenserver/projectstore/projectstore.cpp b/src/zenserver/projectstore/projectstore.cpp
index 4ddbdded7..4402e4486 100644
--- a/src/zenserver/projectstore/projectstore.cpp
+++ b/src/zenserver/projectstore/projectstore.cpp
@@ -1239,15 +1239,37 @@ ProjectStore::Project::ReadAccessTimes()
 
 	if (ValidationError == CbValidateError::None)
 	{
-		CbObject	Reader			= LoadCompactBinaryObject(Obj);
-		CbArrayView LastAccessTimes = Reader["lastaccess"sv].AsArrayView();
+		CbObject Reader = LoadCompactBinaryObject(Obj);
 
-		for (CbFieldView& Entry : LastAccessTimes)
+		uint64_t Count = Reader["count"sv].AsUInt64(0);
+		if (Count > 0)
 		{
-			CbObjectView	 AccessTime = Entry.AsObjectView();
-			std::string_view Id			= AccessTime["id"sv].AsString();
-			GcClock::Tick	 AccessTick = AccessTime["tick"sv].AsUInt64();
-			m_LastAccessTimes.insert_or_assign(std::string(Id), AccessTick);
+			std::vector<uint64_t> Ticks;
+			Ticks.reserve(Count);
+			CbArrayView TicksArray = Reader["ticks"sv].AsArrayView();
+			for (CbFieldView& TickView : TicksArray)
+			{
+				Ticks.emplace_back(TickView.AsUInt64());
+			}
+			CbArrayView IdArray = Reader["ids"sv].AsArrayView();
+			uint64_t	Index	= 0;
+			for (CbFieldView& IdView : IdArray)
+			{
+				std::string_view Id = IdView.AsString();
+				m_LastAccessTimes.insert_or_assign(std::string(Id), Ticks[Index++]);
+			}
+		}
+
+		////// Legacy format read
+		{
+			CbArrayView LastAccessTimes = Reader["lastaccess"sv].AsArrayView();
+			for (CbFieldView& Entry : LastAccessTimes)
+			{
+				CbObjectView	 AccessTime = Entry.AsObjectView();
+				std::string_view Id			= AccessTime["id"sv].AsString();
+				GcClock::Tick	 AccessTick = AccessTime["tick"sv].AsUInt64();
+				m_LastAccessTimes.insert_or_assign(std::string(Id), AccessTick);
+			}
 		}
 	}
 	else
@@ -1261,26 +1283,27 @@ ProjectStore::Project::WriteAccessTimes()
 {
 	using namespace std::literals;
 
-	RwLock::ExclusiveLockScope _(m_ProjectLock);
+	CbObjectWriter Writer;
 
-	BinaryWriter Mem;
+	Writer.AddInteger("count", gsl::narrow<uint64_t>(m_LastAccessTimes.size()));
+	Writer.BeginArray("ids");
 
-	CbObjectWriter Writer;
-	Writer.BeginArray("lastaccess");
 	{
+		RwLock::SharedLockScope _(m_ProjectLock);
 		for (const auto& It : m_LastAccessTimes)
 		{
-			Writer.BeginObject();
-			{
-				Writer << "id"sv << It.first;
-				Writer << "tick"sv << gsl::narrow<uint64_t>(It.second);
-			}
-			Writer.EndObject();
+			Writer << It.first;
 		}
+		Writer.EndArray();
+		Writer.BeginArray("ticks");
+		for (const auto& It : m_LastAccessTimes)
+		{
+			Writer << gsl::narrow<uint64_t>(It.second);
+		}
+		Writer.EndArray();
 	}
-	Writer.EndArray();
 
-	Writer.Save(Mem);
+	CbObject Data = Writer.Save();
 
 	try
 	{
@@ -1290,10 +1313,7 @@ ProjectStore::Project::WriteAccessTimes()
 
 		ZEN_INFO("persisting access times for project '{}' to {}", Identifier, ProjectAccessTimesFilePath);
 
-		BasicFile Blob;
-		Blob.Open(ProjectAccessTimesFilePath, BasicFile::Mode::kTruncate);
-		Blob.Write(Mem.Data(), Mem.Size(), 0);
-		Blob.Flush();
+		WriteFile(ProjectAccessTimesFilePath, Data.GetBuffer().AsIoBuffer());
 	}
 	catch (std::exception& Err)
 	{