diff --git a/src/EcsAspect.cs b/src/EcsAspect.cs
index b2fc09b..b96e091 100644
--- a/src/EcsAspect.cs
+++ b/src/EcsAspect.cs
@@ -2,7 +2,7 @@
 using DCFApixels.DragonECS.PoolsCore;
 using System;
 using System.Collections.Generic;
-using System.Runtime.CompilerServices;
+using static DCFApixels.DragonECS.EcsAspect;
 
 namespace DCFApixels.DragonECS
 {
@@ -138,29 +138,6 @@ namespace DCFApixels.DragonECS
                 builder.Build(out newAspect._mask);
                 newAspect._isBuilt = true;
 
-                newAspect._sortIncBuffer = new UnsafeArray<int>(newAspect._mask._inc.Length, true);
-                newAspect._sortExcBuffer = new UnsafeArray<int>(newAspect._mask._exc.Length, true);
-                newAspect._sortIncChunckBuffer = new UnsafeArray<EcsMaskChunck>(newAspect._mask._incChunckMasks.Length, true);
-                newAspect._sortExcChunckBuffer = new UnsafeArray<EcsMaskChunck>(newAspect._mask._excChunckMasks.Length, true);
-
-                for (int i = 0; i < newAspect._sortIncBuffer.Length; i++)
-                {
-                    newAspect._sortIncBuffer.ptr[i] = newAspect._mask._inc[i];
-                }
-                for (int i = 0; i < newAspect._sortExcBuffer.Length; i++)
-                {
-                    newAspect._sortExcBuffer.ptr[i] = newAspect._mask._exc[i];
-                }
-
-                for (int i = 0; i < newAspect._sortIncChunckBuffer.Length; i++)
-                {
-                    newAspect._sortIncChunckBuffer.ptr[i] = newAspect._mask._incChunckMasks[i];
-                }
-                for (int i = 0; i < newAspect._sortExcChunckBuffer.Length; i++)
-                {
-                    newAspect._sortExcChunckBuffer.ptr[i] = newAspect._mask._excChunckMasks[i];
-                }
-
                 return (TAspect)newAspect;
             }
 
@@ -224,27 +201,6 @@ namespace DCFApixels.DragonECS
         }
         #endregion
 
-        #region Finalizator
-        unsafe ~EcsAspect()
-        {
-            _sortIncBuffer.Dispose();
-            _sortExcBuffer.Dispose();
-            _sortIncChunckBuffer.Dispose();
-            _sortExcChunckBuffer.Dispose();
-        }
-        #endregion
-
-        #region Iterator
-        public Iterator GetIterator()
-        {
-            return new Iterator(this, _source.Entities);
-        }
-        public Iterator GetIteratorFor(EcsSpan span)
-        {
-            return new Iterator(this, span);
-        }
-        #endregion
-
         #region Combined
         private readonly struct Combined
         {
@@ -259,17 +215,48 @@ namespace DCFApixels.DragonECS
         #endregion
 
         #region Iterator
+        [Obsolete("Use EcsMask.GetIterator()")]
+        public Iterator GetIterator()
+        {
+            return new Iterator(Mask.GetIterator(), _source.Entities);
+        }
+        [Obsolete("Use EcsMask.GetIterator().Iterate(span)")]
+        public Iterator GetIteratorFor(EcsSpan span)
+        {
+            return new Iterator(Mask.GetIterator(), span);
+        }
+        [Obsolete("Use EcsMaskIterator")]
         public ref struct Iterator
         {
             public readonly short worldID;
-            public readonly EcsAspect aspect;
+            public readonly EcsMaskIterator.Enumerable iterator;
             private EcsSpan _span;
 
-            public Iterator(EcsAspect aspect, EcsSpan span)
+            public Iterator(EcsMaskIterator iterator, EcsSpan span)
             {
-                worldID = aspect.World.id;
+                worldID = iterator.World.id;
                 _span = span;
-                this.aspect = aspect;
+                this.iterator = iterator.Iterate(span);
+            }
+
+            #region CopyTo
+            public void CopyTo(EcsGroup group)
+            {
+                iterator.CopyTo(group);
+            }
+            public int CopyTo(ref int[] array)
+            {
+                return iterator.CopyTo(ref array);
+            }
+            public EcsSpan CopyToSpan(ref int[] array)
+            {
+                return iterator.CopyToSpan(ref array);
+            }
+            #endregion
+
+            public EcsMaskIterator.Enumerable.Enumerator GetEnumerator()
+            {
+                return iterator.GetEnumerator();
             }
         }
         #endregion
diff --git a/src/EcsMask.cs b/src/EcsMask.cs
index 1e7434e..af5a6db 100644
--- a/src/EcsMask.cs
+++ b/src/EcsMask.cs
@@ -651,6 +651,11 @@ namespace DCFApixels.DragonECS
     }
     #endregion
 
+    #region EcsMaskIterator
+#if ENABLE_IL2CPP
+    [Il2CppSetOption (Option.NullChecks, false)]
+    [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
+#endif
     public class EcsMaskIterator
     {
         #region CountStructComparers
@@ -689,10 +694,43 @@ namespace DCFApixels.DragonECS
         private UnsafeArray<EcsMaskChunck> _sortExcChunckBuffer;
 
         #region Constructors
-        public EcsMaskIterator(EcsWorld source, EcsMask mask)
+        public unsafe EcsMaskIterator(EcsWorld source, EcsMask mask)
         {
             _source = source;
             _mask = mask;
+
+            _sortIncBuffer = new UnsafeArray<int>(_mask._inc.Length, true);
+            _sortExcBuffer = new UnsafeArray<int>(_mask._exc.Length, true);
+            _sortIncChunckBuffer = new UnsafeArray<EcsMaskChunck>(_mask._incChunckMasks.Length, true);
+            _sortExcChunckBuffer = new UnsafeArray<EcsMaskChunck>(_mask._excChunckMasks.Length, true);
+
+            for (int i = 0; i < _sortIncBuffer.Length; i++)
+            {
+                _sortIncBuffer.ptr[i] = _mask._inc[i];
+            }
+            for (int i = 0; i < _sortExcBuffer.Length; i++)
+            {
+                _sortExcBuffer.ptr[i] = _mask._exc[i];
+            }
+
+            for (int i = 0; i < _sortIncChunckBuffer.Length; i++)
+            {
+                _sortIncChunckBuffer.ptr[i] = _mask._incChunckMasks[i];
+            }
+            for (int i = 0; i < _sortExcChunckBuffer.Length; i++)
+            {
+                _sortExcChunckBuffer.ptr[i] = _mask._excChunckMasks[i];
+            }
+        }
+        #endregion
+
+        #region Finalizator
+        unsafe ~EcsMaskIterator()
+        {
+            _sortIncBuffer.Dispose();
+            _sortExcBuffer.Dispose();
+            _sortIncChunckBuffer.Dispose();
+            _sortExcChunckBuffer.Dispose();
         }
         #endregion
 
@@ -911,4 +949,5 @@ namespace DCFApixels.DragonECS
         }
         #endregion
     }
+    #endregion
 }
diff --git a/src/EcsWorld.cache.cs b/src/EcsWorld.cache.cs
index 57ad1ab..8ee4d57 100644
--- a/src/EcsWorld.cache.cs
+++ b/src/EcsWorld.cache.cs
@@ -32,18 +32,18 @@ namespace DCFApixels.DragonECS
                 component = default;
             }
         }
-        internal readonly struct ExcecutorCache<T> : IEcsWorldComponent<ExcecutorCache<T>>
+        internal readonly struct ExeccutorCache<T> : IEcsWorldComponent<ExeccutorCache<T>>
             where T : EcsQueryExecutor, new()
         {
             public readonly T instance;
-            public ExcecutorCache(T instance) => this.instance = instance;
-            void IEcsWorldComponent<ExcecutorCache<T>>.Init(ref ExcecutorCache<T> component, EcsWorld world)
+            public ExeccutorCache(T instance) => this.instance = instance;
+            void IEcsWorldComponent<ExeccutorCache<T>>.Init(ref ExeccutorCache<T> component, EcsWorld world)
             {
                 T instance = new T();
-                instance.Initialize(world);
-                component = new ExcecutorCache<T>(instance);
+                instance.Initialize(world, world._executorsMediator);
+                component = new ExeccutorCache<T>(instance);
             }
-            void IEcsWorldComponent<ExcecutorCache<T>>.OnDestroy(ref ExcecutorCache<T> component, EcsWorld world)
+            void IEcsWorldComponent<ExeccutorCache<T>>.OnDestroy(ref ExeccutorCache<T> component, EcsWorld world)
             {
                 component = default;
             }
diff --git a/src/EcsWorld.cs b/src/EcsWorld.cs
index 947623a..398c05e 100644
--- a/src/EcsWorld.cs
+++ b/src/EcsWorld.cs
@@ -166,10 +166,11 @@ namespace DCFApixels.DragonECS
             _worlds[worldID] = this;
 
             _poolsMediator = new PoolsMediator(this);
+            _executorsMediator = new ExecutorMediator(this);
 
             int poolsCapacity = ArrayUtility.NormalizeSizeToPowerOfTwo(config.PoolsCapacity);
             _pools = new IEcsPoolImplementation[poolsCapacity];
-            _poolSlots = new int[poolsCapacity];
+            _poolSlots = new PoolSlot[poolsCapacity];
             ArrayUtility.Fill(_pools, _nullPool);
 
             int entitiesCapacity = ArrayUtility.NormalizeSizeToPowerOfTwo(config.EntitiesCapacity);
@@ -218,7 +219,7 @@ namespace DCFApixels.DragonECS
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public TExecutor GetExecutor<TExecutor>() where TExecutor : EcsQueryExecutor, new()
         {
-            return Get<ExcecutorCache<TExecutor>>().instance;
+            return Get<ExeccutorCache<TExecutor>>().instance;
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
diff --git a/src/Executors/EcsQueryExecutor.cs b/src/Executors/EcsQueryExecutor.cs
index fc7b1b5..4e3470f 100644
--- a/src/Executors/EcsQueryExecutor.cs
+++ b/src/Executors/EcsQueryExecutor.cs
@@ -1,8 +1,39 @@
-using System.Runtime.CompilerServices;
+using System;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 
 namespace DCFApixels.DragonECS
 {
-    public abstract class EcsQueryExecutor
+    public partial class EcsWorld
+    {
+        private readonly Dictionary<(Type, Type), EcsQueryExecutorCore> _executorCoures = new Dictionary<(Type, Type), EcsQueryExecutorCore>();
+        private readonly ExecutorMediator _executorsMediator;
+        public readonly struct ExecutorMediator
+        {
+            public readonly EcsWorld World;
+            internal ExecutorMediator(EcsWorld world)
+            {
+                if (world == null || world._executorsMediator.World != null)
+                {
+                    throw new InvalidOperationException();
+                }
+                World = world;
+            }
+            public TExecutorCore GetCore<TExecutorCore>(Type aspectType)
+                where TExecutorCore : EcsQueryExecutorCore, new()
+            {
+                var coreType = typeof(EcsQueryExecutorCore);
+                if(World._executorCoures.TryGetValue((aspectType, coreType), out EcsQueryExecutorCore core))
+                {
+                    core = new TExecutorCore();
+                    core.Initialize(World);
+                    World._executorCoures.Add((aspectType, coreType), core);
+                }
+                return (TExecutorCore)core;
+            }
+        }
+    }
+    public abstract class EcsQueryExecutorCore
     {
         private EcsWorld _source;
         public short WorldID
@@ -15,7 +46,6 @@ namespace DCFApixels.DragonECS
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get { return _source; }
         }
-        public abstract long Version { get; }
         internal void Initialize(EcsWorld world)
         {
             _source = world;
@@ -29,13 +59,47 @@ namespace DCFApixels.DragonECS
         protected abstract void OnInitialize();
         protected abstract void OnDestroy();
     }
+    public abstract class EcsQueryExecutor
+    {
+        private EcsWorld _source;
+        private EcsWorld.ExecutorMediator _mediator;
+        public short WorldID
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get { return _source.id; }
+        }
+        public EcsWorld World
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get { return _source; }
+        }
+        protected EcsWorld.ExecutorMediator Mediator
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get { return _mediator; }
+        }
+        public abstract long Version { get; }
+        internal void Initialize(EcsWorld world, EcsWorld.ExecutorMediator mediator)
+        {
+            _source = world;
+            _mediator = mediator;
+            OnInitialize();
+        }
+        internal void Destroy()
+        {
+            OnDestroy();
+            _source = null;
+        }
+        protected abstract void OnInitialize();
+        protected abstract void OnDestroy();
+    }
 
     public readonly struct PoolVersionsChecker
     {
         private readonly EcsMask _mask;
         private readonly long[] _versions;
 
-        public PoolVersionsChecker(EcsMask mask) : this()
+        public PoolVersionsChecker(EcsMask mask)
         {
             _mask = mask;
             _versions = new long[mask._inc.Length + mask._exc.Length];
diff --git a/src/Executors/EcsWhereExecutor.cs b/src/Executors/EcsWhereExecutor.cs
index 72fa2ee..0d20c42 100644
--- a/src/Executors/EcsWhereExecutor.cs
+++ b/src/Executors/EcsWhereExecutor.cs
@@ -1,51 +1,89 @@
 using DCFApixels.DragonECS.Internal;
+using System;
 using System.Runtime.CompilerServices;
+#if ENABLE_IL2CPP
+using Unity.IL2CPP.CompilerServices;
+#endif
 
-namespace DCFApixels.DragonECS
+namespace DCFApixels.DragonECS.Internal
 {
 #if ENABLE_IL2CPP
-    using Unity.IL2CPP.CompilerServices;
     [Il2CppSetOption(Option.NullChecks, false)]
     [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
 #endif
-    public sealed class EcsWhereExecutor<TAspect> : EcsQueryExecutor where TAspect : EcsAspect, new()
+    internal readonly struct EcsWhereExecutorCoreList : IEcsWorldComponent<EcsWhereExecutorCoreList>
     {
-        private TAspect _aspect;
-        private int[] _filteredEntities;
-        private int _filteredEntitiesCount;
+        internal readonly EcsWhereExecutorCore[] _cores;
+        public EcsWhereExecutorCoreList(EcsWhereExecutorCore[] cores)
+        {
+            _cores = cores;
+        }
+        public void Init(ref EcsWhereExecutorCoreList component, EcsWorld world)
+        {
+            component = new EcsWhereExecutorCoreList(new EcsWhereExecutorCore[64]);
+        }
+        public void OnDestroy(ref EcsWhereExecutorCoreList component, EcsWorld world)
+        {
+            component = default;
+        }
+    }
 
-        private long _lastWorldVersion;
+#if ENABLE_IL2CPP
+    [Il2CppSetOption(Option.NullChecks, false)]
+    [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
+#endif
+    internal class EcsWhereExecutorCore
+    {
+        private EcsWorld _source;
+
+        private EcsMaskIterator _iterator;
+        private int[] _filteredEntities = new int[32];
+        private int _filteredEntitiesCount = 0;
+
+        private long _lastWorldVersion = 0;
         private PoolVersionsChecker _versionsChecker;
 
         #region Properties
-        public TAspect Aspect
+        public long Version
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _aspect;
-        }
-        public sealed override long Version
-        {
-            [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _lastWorldVersion;
+            get { return _lastWorldVersion; }
         }
         #endregion
 
-        #region OnInitialize/OnDestroy
-        protected sealed override void OnInitialize()
+        #region Constructors
+        public EcsWhereExecutorCore(EcsWorld source, EcsAspect aspect)
         {
-            _aspect = World.GetAspect<TAspect>();
-            _filteredEntities = new int[32];
-            _versionsChecker = new PoolVersionsChecker(_aspect._mask);
+            _source = source;
+            _versionsChecker = new PoolVersionsChecker(aspect.Mask);
         }
-        protected sealed override void OnDestroy() { }
         #endregion
 
         #region Methods
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void Filter(EcsSpan span)
         {
-            _filteredEntitiesCount = _aspect.GetIteratorFor(span).CopyTo(ref _filteredEntities);
-            _lastWorldVersion = World.Version;
+            _filteredEntitiesCount = _iterator.Iterate(span).CopyTo(ref _filteredEntities);
+            _lastWorldVersion = _source.Version;
+        }
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public EcsSpan Execute()
+        {
+            return ExecuteFor(_source.Entities);
+        }
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public EcsSpan ExecuteFor(EcsSpan span)
+        {
+#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
+            if (span.IsNull) { Throw.ArgumentNull(nameof(span)); }
+            if (span.WorldID != _source.id) { Throw.Quiery_ArgumentDifferentWorldsException(); }
+#endif
+            _source.ReleaseDelEntityBufferAllAuto();
+            if (_lastWorldVersion != _source.Version || _versionsChecker.NextEquals() == false)
+            {
+                Filter(span);
+            }
+            return new EcsSpan(_source.id, _filteredEntities, _filteredEntitiesCount);
         }
 
         //        [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -67,25 +105,66 @@ namespace DCFApixels.DragonECS
         //            }
         //            Array.Sort<int>(_filteredEntities, 0, _filteredEntitiesCount, comparison);
         //        }
+        #endregion
+    }
+}
 
+namespace DCFApixels.DragonECS
+{
+#if ENABLE_IL2CPP
+    [Il2CppSetOption(Option.NullChecks, false)]
+    [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
+#endif
+    public sealed class EcsWhereExecutor<TAspect> : EcsQueryExecutor where TAspect : EcsAspect, new()
+    {
+        private TAspect _aspect;
+        private EcsWhereExecutorCore _core;
+
+        #region Properties
+        public TAspect Aspect
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get { return _aspect; }
+        }
+        public sealed override long Version
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get { return _core.Version; }
+        }
+        #endregion
+
+        #region OnInitialize/OnDestroy
+        protected sealed override void OnInitialize()
+        {
+            _aspect = World.GetAspect<TAspect>();
+            int maskID = _aspect.Mask.ID;
+            ref var list = ref World.Get<EcsWhereExecutorCoreList>();
+            var cores = list._cores;
+            if (maskID >= list._cores.Length)
+            {
+                Array.Resize(ref cores, cores.Length << 1);
+                list = new EcsWhereExecutorCoreList(cores);
+            }
+            ref var coreRef = ref cores[maskID];
+            if (coreRef == null)
+            {
+                coreRef = new EcsWhereExecutorCore(World, _aspect);
+            }
+            _core = coreRef;
+        }
+        protected sealed override void OnDestroy() { }
+        #endregion
+
+        #region Methods
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public EcsSpan Execute()
         {
-            return ExecuteFor(_aspect.World.Entities);
+            return _core.Execute();
         }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public EcsSpan ExecuteFor(EcsSpan span)
         {
-#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-            if (span.IsNull) { Throw.ArgumentNull(nameof(span)); }
-            if (span.WorldID != WorldID) { Throw.Quiery_ArgumentDifferentWorldsException(); }
-#endif
-            World.ReleaseDelEntityBufferAllAuto();
-            if (_lastWorldVersion != World.Version || _versionsChecker.NextEquals() == false)
-            {
-                Filter(span);
-            }
-            return new EcsSpan(WorldID, _filteredEntities, _filteredEntitiesCount);
+            return _core.ExecuteFor(span);
         }
         #endregion
     }
diff --git a/src/Executors/EcsWhereToGroupExecutor.cs b/src/Executors/EcsWhereToGroupExecutor.cs
index 357fd49..79ff3e0 100644
--- a/src/Executors/EcsWhereToGroupExecutor.cs
+++ b/src/Executors/EcsWhereToGroupExecutor.cs
@@ -1,35 +1,117 @@
 using DCFApixels.DragonECS.Internal;
 using System.Runtime.CompilerServices;
+#if ENABLE_IL2CPP
+using Unity.IL2CPP.CompilerServices;
+#endif
+
+namespace DCFApixels.DragonECS.Internal
+{
+#if ENABLE_IL2CPP
+    [Il2CppSetOption(Option.NullChecks, false)]
+    [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
+#endif
+    internal readonly struct EcsWhereToGroupExecutorCoreList : IEcsWorldComponent<EcsWhereToGroupExecutorCoreList>
+    {
+        internal readonly EcsWhereToGroupExecutorCore[] _cores;
+        public EcsWhereToGroupExecutorCoreList(EcsWhereToGroupExecutorCore[] cores)
+        {
+            _cores = cores;
+        }
+        public void Init(ref EcsWhereToGroupExecutorCoreList component, EcsWorld world)
+        {
+            component = new EcsWhereToGroupExecutorCoreList(new EcsWhereToGroupExecutorCore[64]);
+        }
+        public void OnDestroy(ref EcsWhereToGroupExecutorCoreList component, EcsWorld world)
+        {
+            component = default;
+        }
+    }
+
+#if ENABLE_IL2CPP
+    [Il2CppSetOption(Option.NullChecks, false)]
+    [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
+#endif
+    internal class EcsWhereToGroupExecutorCore
+    {
+        private EcsWorld _source;
+
+        private EcsMaskIterator _iterator;
+        private EcsGroup _filteredGroup;
+
+        private long _lastWorldVersion;
+        private PoolVersionsChecker _versionsChecker;
+
+        #region Properties
+        public long Version
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get { return _lastWorldVersion; }
+        }
+        #endregion
+
+        #region Constructors/Destroy
+        public EcsWhereToGroupExecutorCore(EcsWorld source, EcsAspect aspect)
+        {
+            _source = source;
+            _versionsChecker = new PoolVersionsChecker(aspect.Mask);
+        }
+        public void Destroy()
+        {
+            _filteredGroup.Dispose();
+        }
+        #endregion
+
+        #region Methods
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private void Filter(EcsSpan span)
+        {
+            _iterator.Iterate(span).CopyTo(_filteredGroup);
+            _lastWorldVersion = _source.Version;
+        }
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public EcsSpan Execute()
+        {
+            return ExecuteFor(_source.Entities);
+        }
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public EcsSpan ExecuteFor(EcsSpan span)
+        {
+#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
+            if (span.IsNull) { Throw.ArgumentNull(nameof(span)); }
+            if (span.WorldID != _source.id) { Throw.Quiery_ArgumentDifferentWorldsException(); }
+#endif
+            _source.ReleaseDelEntityBufferAllAuto();
+            if (_lastWorldVersion != _source.Version || _versionsChecker.NextEquals() == false)
+            {
+                Filter(span);
+            }
+            return _filteredGroup.Readonly;
+        }
+        #endregion
+    }
+}
 
 namespace DCFApixels.DragonECS
 {
 #if ENABLE_IL2CPP
-    using Unity.IL2CPP.CompilerServices;
     [Il2CppSetOption(Option.NullChecks, false)]
     [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
 #endif
     public sealed class EcsWhereToGroupExecutor<TAspect> : EcsQueryExecutor where TAspect : EcsAspect, new()
     {
         private TAspect _aspect;
-        private EcsGroup _filteredGroup;
-
-        private long _lastWorldVersion;
-        private PoolVersionsChecker _versionsChecker;
-
-#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-        private readonly EcsProfilerMarker _executeMarker = new EcsProfilerMarker("Where");
-#endif
+        private EcsWhereToGroupExecutorCore _core;
 
         #region Properties
         public TAspect Aspect
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _aspect;
+            get { return _aspect; }
         }
         public sealed override long Version
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _lastWorldVersion;
+            get { return _core.Version; }
         }
         #endregion
 
@@ -42,39 +124,20 @@ namespace DCFApixels.DragonECS
         }
         protected sealed override void OnDestroy()
         {
-            _filteredGroup.Dispose();
+            _core.Destroy();
         }
         #endregion
 
         #region Methods
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private void Filter(EcsSpan span)
+        public EcsSpan Execute()
         {
-            _aspect.GetIteratorFor(span).CopyTo(_filteredGroup);
-            _lastWorldVersion = World.Version;
+            return _core.Execute();
         }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsReadonlyGroup Execute()
+        public EcsSpan ExecuteFor(EcsSpan span)
         {
-            return ExecuteFor(_aspect.World.Entities);
-        }
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsReadonlyGroup ExecuteFor(EcsSpan span)
-        {
-#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-            _executeMarker.Begin();
-            if (span.IsNull) { Throw.ArgumentNull(nameof(span)); }
-            if (span.WorldID != WorldID) { Throw.Quiery_ArgumentDifferentWorldsException(); }
-#endif
-            World.ReleaseDelEntityBufferAllAuto();
-            if (_lastWorldVersion != World.Version || _versionsChecker.NextEquals() == false)
-            {
-                Filter(span);
-            }
-#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-            _executeMarker.End();
-#endif
-            return _filteredGroup.Readonly;
+            return _core.ExecuteFor(span);
         }
         #endregion
     }