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, 33 insertions, 29 deletions

diff --git a/src/zenserver/cache/structuredcachestore.cpp b/src/zenserver/cache/structuredcachestore.cpp
index 0a2947b16..1b6eeca3a 100644
--- a/src/zenserver/cache/structuredcachestore.cpp
+++ b/src/zenserver/cache/structuredcachestore.cpp
@@ -1030,46 +1030,50 @@ TEST_CASE("z$.gc")
 	{
 		ScopedTemporaryDirectory TempDir;
 		GcManager				 Gc;
-		ZenCacheNamespace		 Zcs(Gc, *JobQueue, TempDir.Path() / "cache");
-		const auto				 Bucket = "rightintwo"sv;
-
-		std::vector<IoHash> Keys{CreateKey(1), CreateKey(2), CreateKey(3)};
-
-		for (const auto& Key : Keys)
 		{
-			IoBuffer Value = testutils::CreateBinaryCacheValue(128);
-			Zcs.Put(Bucket, Key, {.Value = Value});
-		}
-
-		{
-			GcContext GcCtx(GcClock::Now() - std::chrono::hours(2), GcClock::Now() - std::chrono::hours(2));
-			GcCtx.CollectSmallObjects(true);
+			ZenCacheNamespace Zcs(Gc, *JobQueue, TempDir.Path() / "cache");
+			const auto		  Bucket = "rightintwo"sv;
 
-			Gc.CollectGarbage(GcCtx);
+			std::vector<IoHash> Keys{CreateKey(1), CreateKey(2), CreateKey(3)};
 
 			for (const auto& Key : Keys)
 			{
-				ZenCacheValue CacheValue;
-				const bool	  Exists = Zcs.Get(Bucket, Key, CacheValue);
-				CHECK(Exists);
+				IoBuffer Value = testutils::CreateBinaryCacheValue(128);
+				Zcs.Put(Bucket, Key, {.Value = Value});
 			}
-		}
 
-		// Move forward in time and collect again
-		{
-			GcContext GcCtx(GcClock::Now() + std::chrono::minutes(2), GcClock::Now() + std::chrono::minutes(2));
-			GcCtx.CollectSmallObjects(true);
+			{
+				GcContext GcCtx(GcClock::Now() - std::chrono::hours(2), GcClock::Now() - std::chrono::hours(2));
+				GcCtx.CollectSmallObjects(true);
 
-			Zcs.Flush();
-			Gc.CollectGarbage(GcCtx);
+				Gc.CollectGarbage(GcCtx);
 
-			for (const auto& Key : Keys)
-			{
-				ZenCacheValue CacheValue;
-				const bool	  Exists = Zcs.Get(Bucket, Key, CacheValue);
-				CHECK(!Exists);
+				for (const auto& Key : Keys)
+				{
+					ZenCacheValue CacheValue;
+					const bool	  Exists = Zcs.Get(Bucket, Key, CacheValue);
+					CHECK(Exists);
+				}
 			}
 
+			// Move forward in time and collect again
+			{
+				GcContext GcCtx(GcClock::Now() + std::chrono::minutes(2), GcClock::Now() + std::chrono::minutes(2));
+				GcCtx.CollectSmallObjects(true);
+
+				Zcs.Flush();
+				Gc.CollectGarbage(GcCtx);
+
+				for (const auto& Key : Keys)
+				{
+					ZenCacheValue CacheValue;
+					const bool	  Exists = Zcs.Get(Bucket, Key, CacheValue);
+					CHECK(!Exists);
+				}
+			}
+		}
+		{
+			ZenCacheNamespace Zcs(Gc, *JobQueue, TempDir.Path() / "cache");
 			CHECK_EQ(0, Zcs.StorageSize().DiskSize);
 		}
 	}