diff --git a/DD.Persistence.API/Controllers/TimestampedValuesController.cs b/DD.Persistence.API/Controllers/TimestampedValuesController.cs
index 759d88a..abc1114 100644
--- a/DD.Persistence.API/Controllers/TimestampedValuesController.cs
+++ b/DD.Persistence.API/Controllers/TimestampedValuesController.cs
@@ -35,7 +35,7 @@ public class TimestampedValuesController : ControllerBase
     {
         var result = await timestampedValuesRepository.AddRange(discriminatorId, dtos, token);
 
-        return Ok(result);
+        return CreatedAtAction(nameof(AddRange), result);
     }
 
     /// <summary>
diff --git a/DD.Persistence.Client/Clients/Base/BaseClient.cs b/DD.Persistence.Client/Clients/Base/BaseClient.cs
index f9bcdd7..3b13cdb 100644
--- a/DD.Persistence.Client/Clients/Base/BaseClient.cs
+++ b/DD.Persistence.Client/Clients/Base/BaseClient.cs
@@ -12,13 +12,13 @@ public abstract class BaseClient
 		this.logger = logger;
 	}
 
-    public async Task<T> ExecuteGetResponse<T>(Func<Task<IApiResponse<T>>> getMethod, CancellationToken token)
+    public async Task<T?> ExecuteGetResponse<T>(Func<Task<IApiResponse<T>>> getMethod, CancellationToken token)
     {
         var response = await getMethod.Invoke().WaitAsync(token);
 
 		if (response.IsSuccessStatusCode)
         {
-			return response.Content!;
+			return response.Content;
 		}
 
 		var exception = response.GetPersistenceException();
diff --git a/DD.Persistence.Client/Clients/Interfaces/ITimestampedValuesClient.cs b/DD.Persistence.Client/Clients/Interfaces/ITimestampedValuesClient.cs
index 9c9f262..b0ea180 100644
--- a/DD.Persistence.Client/Clients/Interfaces/ITimestampedValuesClient.cs
+++ b/DD.Persistence.Client/Clients/Interfaces/ITimestampedValuesClient.cs
@@ -96,7 +96,6 @@ public interface ITimestampedValuesClient : IDisposable
     /// </summary>
     /// <typeparam name="T"></typeparam>
     /// <param name="idDiscriminator"></param>
-    /// <param name="columnNames"></param>
     /// <param name="take"></param>
     /// <param name="token"></param>
     /// <returns></returns>
diff --git a/DD.Persistence.Repository/Repositories/TimestampedValuesRepository.cs b/DD.Persistence.Repository/Repositories/TimestampedValuesRepository.cs
index b2f8203..204b1a2 100644
--- a/DD.Persistence.Repository/Repositories/TimestampedValuesRepository.cs
+++ b/DD.Persistence.Repository/Repositories/TimestampedValuesRepository.cs
@@ -92,6 +92,7 @@ public class TimestampedValuesRepository : ITimestampedValuesRepository
         return result;
     }
 
+    // ToDo: прореживание должно осуществляться до материализации
     public async virtual Task<IEnumerable<Tuple<DateTimeOffset, object[]>>> GetResampledData(
         Guid discriminatorId,
         DateTimeOffset dateBegin,
diff --git a/DD.Persistence/Services/TimestampedValuesService.cs b/DD.Persistence/Services/TimestampedValuesService.cs
index 2b7fc6f..d6d6bf4 100644
--- a/DD.Persistence/Services/TimestampedValuesService.cs
+++ b/DD.Persistence/Services/TimestampedValuesService.cs
@@ -22,6 +22,7 @@ public class TimestampedValuesService : ITimestampedValuesService
     /// <inheritdoc/>
     public async Task<int> AddRange(Guid discriminatorId, IEnumerable<TimestampedValuesDto> dtos, CancellationToken token)
     {
+        // ToDo: реализовать без foreach
         foreach (var dto in dtos)
         {
             var keys = dto.Values.Keys.ToArray();
@@ -132,13 +133,10 @@ public class TimestampedValuesService : ITimestampedValuesService
             };
 
             var identity = systemSpecification!.PropNames;
-            for (var i = 0; i < identity.Count(); i++)
-            {
-                var key = identity[i];
-                var value = entity.Item2[i];
-
-                dto.Values.Add(key, value);
-            }
+            var indexedIdentity = identity
+                .Select((value, index) => new { index, value });
+            dto.Values = indexedIdentity
+                .ToDictionary(x => x.value, x => entity.Item2[x.index]);
 
             return dto;
         });