diff --git a/src/NHibernate/Async/Cache/StandardQueryCache.cs b/src/NHibernate/Async/Cache/StandardQueryCache.cs
index 8d656f86160..ab7d4f4547e 100644
--- a/src/NHibernate/Async/Cache/StandardQueryCache.cs
+++ b/src/NHibernate/Async/Cache/StandardQueryCache.cs
@@ -470,6 +470,9 @@ protected virtual Task<bool> IsUpToDateAsync(ISet<string> spaces, long timestamp
 			{
 				return Task.FromCanceled<bool>(cancellationToken);
 			}
+			if (spaces.Count == 0)
+				return Task.FromResult<bool>(true);
+
 			return _updateTimestampsCache.IsUpToDateAsync(spaces, timestamp, cancellationToken);
 		}
 	}
diff --git a/src/NHibernate/Async/Cache/UpdateTimestampsCache.cs b/src/NHibernate/Async/Cache/UpdateTimestampsCache.cs
index e5ba6ce0e45..f97f25401be 100644
--- a/src/NHibernate/Async/Cache/UpdateTimestampsCache.cs
+++ b/src/NHibernate/Async/Cache/UpdateTimestampsCache.cs
@@ -116,13 +116,9 @@ private Task SetSpacesTimestampAsync(IReadOnlyCollection<string> spaces, long ts
 				if (spaces.Count == 0)
 					return Task.CompletedTask;
 
-				var timestamps = new object[spaces.Count];
-				for (var i = 0; i < timestamps.Length; i++)
-				{
-					timestamps[i] = ts;
-				}
-
-				return _updateTimestamps.PutManyAsync(spaces.ToArray(), timestamps, cancellationToken);
+				return _updateTimestamps.PutManyAsync(
+				spaces.ToArray<object>(),
+				ArrayHelper.Fill<object>(ts, spaces.Count), cancellationToken);
 			}
 			catch (Exception ex)
 			{
@@ -139,13 +135,7 @@ public virtual async Task<bool> IsUpToDateAsync(ISet<string> spaces, long timest
 				if (spaces.Count == 0)
 					return true;
 
-				var keys = new object[spaces.Count];
-				var index = 0;
-				foreach (var space in spaces)
-				{
-					keys[index++] = space;
-				}
-				var lastUpdates = await (_updateTimestamps.GetManyAsync(keys, cancellationToken)).ConfigureAwait(false);
+				var lastUpdates = await (_updateTimestamps.GetManyAsync(spaces.ToArray<object>(), cancellationToken)).ConfigureAwait(false);
 				return lastUpdates.All(lastUpdate => !IsOutdated(lastUpdate as long?, timestamp));
 			}
 		}
@@ -156,7 +146,9 @@ public virtual async Task<bool[]> AreUpToDateAsync(ISet<string>[] spaces, long[]
 			cancellationToken.ThrowIfCancellationRequested();
 			using (await _areUpToDate.LockAsync())
 			{
-				var results = new bool[spaces.Length];
+				if (spaces.Length == 0)
+					return Array.Empty<bool>();
+
 				var allSpaces = new HashSet<string>();
 				foreach (var sp in spaces)
 				{
@@ -164,28 +156,17 @@ public virtual async Task<bool[]> AreUpToDateAsync(ISet<string>[] spaces, long[]
 				}
 
 				if (allSpaces.Count == 0)
-				{
-					for (var i = 0; i < spaces.Length; i++)
-					{
-						results[i] = true;
-					}
+					return ArrayHelper.Fill(true, spaces.Length);
 
-					return results;
-				}
+				var keys = allSpaces.ToArray<object>();
 
-				var keys = new object[allSpaces.Count];
 				var index = 0;
-				foreach (var space in allSpaces)
-				{
-					keys[index++] = space;
-				}
-
-				index = 0;
 				var lastUpdatesBySpace =
 				(await (_updateTimestamps
 					.GetManyAsync(keys, cancellationToken)).ConfigureAwait(false))
 					.ToDictionary(u => keys[index++], u => u as long?);
 
+				var results = new bool[spaces.Length];
 				for (var i = 0; i < spaces.Length; i++)
 				{
 					var timestamp = timestamps[i];
diff --git a/src/NHibernate/Async/Engine/ActionQueue.cs b/src/NHibernate/Async/Engine/ActionQueue.cs
index 521fafc16c5..3a0ab25b1f5 100644
--- a/src/NHibernate/Async/Engine/ActionQueue.cs
+++ b/src/NHibernate/Async/Engine/ActionQueue.cs
@@ -45,7 +45,7 @@ private Task PreInvalidateCachesAsync(CancellationToken cancellationToken)
 			{
 				return Task.FromCanceled<object>(cancellationToken);
 			}
-			if (session.Factory.Settings.IsQueryCacheEnabled)
+			if (session.Factory.Settings.IsQueryCacheEnabled && executedSpaces.Count > 0)
 			{
 				return session.Factory.UpdateTimestampsCache.PreInvalidateAsync(executedSpaces, cancellationToken);
 			}
@@ -165,7 +165,7 @@ public async Task AfterTransactionCompletionAsync(bool success, CancellationToke
 		private async Task InvalidateCachesAsync(CancellationToken cancellationToken)
 		{
 			cancellationToken.ThrowIfCancellationRequested();
-			if (session.Factory.Settings.IsQueryCacheEnabled)
+			if (session.Factory.Settings.IsQueryCacheEnabled && executedSpaces.Count > 0)
 			{
 				await (session.Factory.UpdateTimestampsCache.InvalidateAsync(executedSpaces, cancellationToken)).ConfigureAwait(false);
 			}
diff --git a/src/NHibernate/Cache/StandardQueryCache.cs b/src/NHibernate/Cache/StandardQueryCache.cs
index 5ccdfdb7a0a..8cda99f3815 100644
--- a/src/NHibernate/Cache/StandardQueryCache.cs
+++ b/src/NHibernate/Cache/StandardQueryCache.cs
@@ -551,6 +551,9 @@ private static ICacheAssembler[] GuessTypes(IList cacheable)
 
 		protected virtual bool IsUpToDate(ISet<string> spaces, long timestamp)
 		{
+			if (spaces.Count == 0)
+				return true;
+
 			return _updateTimestampsCache.IsUpToDate(spaces, timestamp);
 		}
 	}
diff --git a/src/NHibernate/Cache/UpdateTimestampsCache.cs b/src/NHibernate/Cache/UpdateTimestampsCache.cs
index 21f37cf8d25..40369e4ac97 100644
--- a/src/NHibernate/Cache/UpdateTimestampsCache.cs
+++ b/src/NHibernate/Cache/UpdateTimestampsCache.cs
@@ -88,13 +88,9 @@ private void SetSpacesTimestamp(IReadOnlyCollection<string> spaces, long ts)
 			if (spaces.Count == 0)
 				return;
 
-			var timestamps = new object[spaces.Count];
-			for (var i = 0; i < timestamps.Length; i++)
-			{
-				timestamps[i] = ts;
-			}
-
-			_updateTimestamps.PutMany(spaces.ToArray(), timestamps);
+			_updateTimestamps.PutMany(
+				spaces.ToArray<object>(),
+				ArrayHelper.Fill<object>(ts, spaces.Count));
 		}
 
 		[MethodImpl(MethodImplOptions.Synchronized)]
@@ -103,20 +99,16 @@ public virtual bool IsUpToDate(ISet<string> spaces, long timestamp /* H2.1 has L
 			if (spaces.Count == 0)
 				return true;
 
-			var keys = new object[spaces.Count];
-			var index = 0;
-			foreach (var space in spaces)
-			{
-				keys[index++] = space;
-			}
-			var lastUpdates = _updateTimestamps.GetMany(keys);
+			var lastUpdates = _updateTimestamps.GetMany(spaces.ToArray<object>());
 			return lastUpdates.All(lastUpdate => !IsOutdated(lastUpdate as long?, timestamp));
 		}
 
 		[MethodImpl(MethodImplOptions.Synchronized)]
 		public virtual bool[] AreUpToDate(ISet<string>[] spaces, long[] timestamps)
 		{
-			var results = new bool[spaces.Length];
+			if (spaces.Length == 0)
+				return Array.Empty<bool>();
+
 			var allSpaces = new HashSet<string>();
 			foreach (var sp in spaces)
 			{
@@ -124,28 +116,17 @@ public virtual bool[] AreUpToDate(ISet<string>[] spaces, long[] timestamps)
 			}
 
 			if (allSpaces.Count == 0)
-			{
-				for (var i = 0; i < spaces.Length; i++)
-				{
-					results[i] = true;
-				}
+				return ArrayHelper.Fill(true, spaces.Length);
 
-				return results;
-			}
+			var keys = allSpaces.ToArray<object>();
 
-			var keys = new object[allSpaces.Count];
 			var index = 0;
-			foreach (var space in allSpaces)
-			{
-				keys[index++] = space;
-			}
-
-			index = 0;
 			var lastUpdatesBySpace =
 				_updateTimestamps
 					.GetMany(keys)
 					.ToDictionary(u => keys[index++], u => u as long?);
 
+			var results = new bool[spaces.Length];
 			for (var i = 0; i < spaces.Length; i++)
 			{
 				var timestamp = timestamps[i];
@@ -163,7 +144,7 @@ public virtual void Destroy()
 			// not the responsibility of this class.
 		}
 
-		private bool IsOutdated(long? lastUpdate, long timestamp)
+		private static bool IsOutdated(long? lastUpdate, long timestamp)
 		{
 			if (!lastUpdate.HasValue)
 			{
diff --git a/src/NHibernate/Engine/ActionQueue.cs b/src/NHibernate/Engine/ActionQueue.cs
index e717adfb426..36a76591edd 100644
--- a/src/NHibernate/Engine/ActionQueue.cs
+++ b/src/NHibernate/Engine/ActionQueue.cs
@@ -172,7 +172,7 @@ private void ExecuteActions<T>(List<T> list) where T: IExecutable
 
 		private void PreInvalidateCaches()
 		{
-			if (session.Factory.Settings.IsQueryCacheEnabled)
+			if (session.Factory.Settings.IsQueryCacheEnabled && executedSpaces.Count > 0)
 			{
 				session.Factory.UpdateTimestampsCache.PreInvalidate(executedSpaces);
 			}
@@ -294,7 +294,7 @@ public void AfterTransactionCompletion(bool success)
 
 		private void InvalidateCaches()
 		{
-			if (session.Factory.Settings.IsQueryCacheEnabled)
+			if (session.Factory.Settings.IsQueryCacheEnabled && executedSpaces.Count > 0)
 			{
 				session.Factory.UpdateTimestampsCache.Invalidate(executedSpaces);
 			}