batch fetch record cache values (#266)

- Improvement: Batch fetch record attachments when appropriate
- Improvement: Reduce memory buffer allocation in BlockStore::IterateBlock
- Improvement: Tweaked BlockStore::IterateBlock logic when to use threaded work (at least 4 chunks requested)
- Bugfix: CasContainerStrategy::IterateChunks could give wrong payload/index when requesting 1 or 2 chunks

1 files changed, 18 insertions, 17 deletions

diff --git a/src/zenstore/compactcas.cpp b/src/zenstore/compactcas.cpp
index 50af7246e..30cf998f8 100644
--- a/src/zenstore/compactcas.cpp
+++ b/src/zenstore/compactcas.cpp
@@ -345,12 +345,13 @@ CasContainerStrategy::IterateChunks(std::span<IoHash>												  ChunkHashes,
 			}
 		}
 	}
-	if (FoundChunkLocations.size() < 3)
+	if (FoundChunkLocations.size() < 4)
 	{
-		for (size_t ChunkIndex : FoundChunkIndexes)
+		for (size_t Index = 0; Index < FoundChunkIndexes.size(); Index++)
 		{
-			IoBuffer Chunk = m_BlockStore.TryGetChunk(FoundChunkLocations[ChunkIndex]);
-			if (!AsyncCallback(ChunkIndex, Chunk))
+			IoBuffer Chunk		= m_BlockStore.TryGetChunk(FoundChunkLocations[Index]);
+			size_t	 OuterIndex = FoundChunkIndexes[Index];
+			if (!AsyncCallback(OuterIndex, Chunk))
 			{
 				return false;
 			}
@@ -359,6 +360,18 @@ CasContainerStrategy::IterateChunks(std::span<IoHash>												  ChunkHashes,
 	}
 
 	auto DoOneBlock = [&](std::span<const size_t> ChunkIndexes) {
+		if (ChunkIndexes.size() < 4)
+		{
+			for (size_t ChunkIndex : ChunkIndexes)
+			{
+				IoBuffer Chunk = m_BlockStore.TryGetChunk(FoundChunkLocations[ChunkIndex]);
+				if (!AsyncCallback(FoundChunkIndexes[ChunkIndex], Chunk))
+				{
+					return false;
+				}
+			}
+			return true;
+		}
 		return m_BlockStore.IterateBlock(
 			FoundChunkLocations,
 			ChunkIndexes,
@@ -378,19 +391,7 @@ CasContainerStrategy::IterateChunks(std::span<IoHash>												  ChunkHashes,
 	Latch			 WorkLatch(1);
 	std::atomic_bool AsyncContinue = true;
 	bool Continue = m_BlockStore.IterateChunks(FoundChunkLocations, [&](uint32_t BlockIndex, std::span<const size_t> ChunkIndexes) {
-		if (ChunkIndexes.size() < 3)
-		{
-			for (size_t ChunkIndex : ChunkIndexes)
-			{
-				IoBuffer Chunk = m_BlockStore.TryGetChunk(FoundChunkLocations[ChunkIndex]);
-				if (!AsyncCallback(FoundChunkIndexes[ChunkIndex], Chunk))
-				{
-					return false;
-				}
-			}
-			return true;
-		}
-		else if (OptionalWorkerPool)
+		if (OptionalWorkerPool && (ChunkIndexes.size() > 3))
 		{
 			WorkLatch.AddCount(1);
 			OptionalWorkerPool->ScheduleWork([&, ChunkIndexes = std::vector<size_t>(ChunkIndexes.begin(), ChunkIndexes.end())]() {