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Fix to #30604 - Implement JSON serialization/deserialization via Utf8…
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…JsonReader/Utf8JsonWriter

Using Utf8JsonReader to read JSON data rather than caching it using DOM. This should reduce allocations significantly. Tricky part is that entity materializers are build in a way that assumes we have random access to all the data we need. This is not the case here.
We read JSON data sequentially and can only do it once, and we don't know the order in which we get the data. This is somewhat problematic in case where entity takes argument in the constructor. Those could be at the very end of the JSON string, so we must read all the data before we can instantiate the object, and populate it's properties and do navigation fixup.
This requires us reading all the JSON data, store them in local variables, and only when we are done reading we instantiate the entity and populate all the properties with data stored in those variables. This adds some allocations (specifically navigations).

We also have to disable de-duplication logic - we can't always safely re-read the JSON string, and definitely can't start reading it from arbitrary position, so now we have to add JSON string for every aggregate projected, even if we already project it's parent.

Serialization implementation (i.e. Utf8JsonWriter) is pretty straighforward.

Also fix to #30993 - Query/Json: data corruption for tracking queries with nested json entities, then updating nested entities outside EF and re-querying

Fix is to recognize and modify shaper in case of tracking query, so that nav expansions are not skipped when parent entity is found in Change Tracker. This is necessary to fix alongside streaming, because now we throw exception from reader (unexpected token) if we don't process the entire stream correctly. Before it would be silently ignored apart from the edge case described in the bug.

Fixes #30604
Fixes #30993
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@maumar
maumar committed Jul 6, 2023
1 parent c8cfc3c commit f23c8cd
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Showing 20 changed files with 1,953 additions and 643 deletions.
16 changes: 1 addition & 15 deletions src/EFCore.Relational/Query/Internal/JsonProjectionInfo.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,12 +19,10 @@ public readonly struct JsonProjectionInfo
/// </summary>
public JsonProjectionInfo(
int jsonColumnIndex,
List<(IProperty?, int?, int?)> keyAccessInfo,
(string?, int?, int?)[] additionalPath)
List<(IProperty?, int?, int?)> keyAccessInfo)
{
JsonColumnIndex = jsonColumnIndex;
KeyAccessInfo = keyAccessInfo;
AdditionalPath = additionalPath;
}

/// <summary>
Expand Down Expand Up @@ -55,16 +53,4 @@ public JsonProjectionInfo(
/// doing so can result in application failures when updating to a new Entity Framework Core release.
/// </remarks>
public List<(IProperty? KeyProperty, int? ConstantKeyValue, int? KeyProjectionIndex)> KeyAccessInfo { get; }

/// <summary>
/// List of additional path elements, only one of the values in the tuple is non-null
/// this information is used to access the correct sub-element of a JsonElement that we materialized
/// </summary>
/// <remarks>
/// This is an internal API that supports the Entity Framework Core infrastructure and not subject to
/// the same compatibility standards as public APIs. It may be changed or removed without notice in
/// any release. You should only use it directly in your code with extreme caution and knowing that
/// doing so can result in application failures when updating to a new Entity Framework Core release.
/// </remarks>
public (string? JsonPropertyName, int? ConstantArrayIndex, int? NonConstantArrayIndex)[] AdditionalPath { get; }
}
10 changes: 2 additions & 8 deletions src/EFCore.Relational/Query/Internal/RelationalProjectionBindingExpressionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,6 @@ private static readonly MethodInfo GetParameterValueMethodInfo

private bool _indexBasedBinding;
private Dictionary<EntityProjectionExpression, ProjectionBindingExpression>? _entityProjectionCache;
private Dictionary<JsonQueryExpression, ProjectionBindingExpression>? _jsonQueryCache;
private List<Expression>? _clientProjections;

private readonly Dictionary<ProjectionMember, Expression> _projectionMapping = new();
Expand Down Expand Up @@ -66,7 +65,6 @@ public virtual Expression Translate(SelectExpression selectExpression, Expressio
{
_indexBasedBinding = true;
_entityProjectionCache = new Dictionary<EntityProjectionExpression, ProjectionBindingExpression>();
_jsonQueryCache = new Dictionary<JsonQueryExpression, ProjectionBindingExpression>();
_projectionMapping.Clear();
_clientProjections = new List<Expression>();

Expand Down Expand Up @@ -307,11 +305,8 @@ protected override Expression VisitExtension(Expression extensionExpression)
{
if (_indexBasedBinding)
{
if (!_jsonQueryCache!.TryGetValue(jsonQueryExpression, out var jsonProjectionBinding))
{
jsonProjectionBinding = AddClientProjection(jsonQueryExpression, typeof(ValueBuffer));
_jsonQueryCache[jsonQueryExpression] = jsonProjectionBinding;
}
_clientProjections!.Add(jsonQueryExpression);
var jsonProjectionBinding = new ProjectionBindingExpression(_selectExpression, _clientProjections.Count - 1, typeof(ValueBuffer));

return entityShaperExpression.Update(jsonProjectionBinding);
}
Expand Down Expand Up @@ -654,7 +649,6 @@ private ProjectionBindingExpression AddClientProjection(Expression expression, T
return new ProjectionBindingExpression(_selectExpression, existingIndex, type);
}

#pragma warning disable IDE0052 // Remove unread private members
private static T GetParameterValue<T>(QueryContext queryContext, string parameterName)
#pragma warning restore IDE0052 // Remove unread private members
=> (T)queryContext.ParameterValues[parameterName]!;
Expand Down
190 changes: 129 additions & 61 deletions ...lShapedQueryCompilingExpressionVisitor.ShaperProcessingExpressionVisitor.ClientMethods.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
using System.Text.Json;
using Microsoft.EntityFrameworkCore.Internal;
using Microsoft.EntityFrameworkCore.Query.Internal;
using Microsoft.EntityFrameworkCore.Storage.Json;

namespace Microsoft.EntityFrameworkCore.Query;

Expand Down Expand Up @@ -67,8 +68,8 @@ private static readonly MethodInfo MaterializeJsonEntityMethodInfo
private static readonly MethodInfo MaterializeJsonEntityCollectionMethodInfo
= typeof(ShaperProcessingExpressionVisitor).GetTypeInfo().GetDeclaredMethod(nameof(MaterializeJsonEntityCollection))!;

private static readonly MethodInfo ExtractJsonPropertyMethodInfo
= typeof(ShaperProcessingExpressionVisitor).GetTypeInfo().GetDeclaredMethod(nameof(ExtractJsonProperty))!;
private static readonly MethodInfo InverseCollectionFixupMethod
= typeof(ShaperProcessingExpressionVisitor).GetTypeInfo().GetDeclaredMethod(nameof(InverseCollectionFixup))!;

[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static TValue ThrowReadValueException<TValue>(
Expand Down Expand Up @@ -123,13 +124,6 @@ private static TValue ThrowExtractJsonPropertyException<TValue>(
exception);
}

private static T? ExtractJsonProperty<T>(JsonElement element, string propertyName, bool nullable)
=> nullable
? element.TryGetProperty(propertyName, out var jsonValue)
? jsonValue.Deserialize<T>()
: default
: element.GetProperty(propertyName).Deserialize<T>();

private static void IncludeReference<TEntity, TIncludingEntity, TIncludedEntity>(
QueryContext queryContext,
TEntity entity,
Expand Down Expand Up @@ -869,105 +863,179 @@ static async Task<RelationalDataReader> InitializeReaderAsync(
dataReaderContext.HasNext = false;
}

private static void IncludeJsonEntityReference<TIncludingEntity, TIncludedEntity>(
private static TEntity? MaterializeJsonEntity<TEntity>(
QueryContext queryContext,
JsonElement? jsonElement,
object[] keyPropertyValues,
TIncludingEntity entity,
Func<QueryContext, object[], JsonElement, TIncludedEntity> innerShaper,
Action<TIncludingEntity, TIncludedEntity> fixup)
where TIncludingEntity : class
where TIncludedEntity : class
JsonReaderData jsonReaderData,
bool nullable,
Func<QueryContext, object[], JsonReaderData, TEntity> shaper)
where TEntity : class
{
if (jsonElement.HasValue && jsonElement.Value.ValueKind != JsonValueKind.Null)
if (jsonReaderData == null)
{
var included = innerShaper(queryContext, keyPropertyValues, jsonElement.Value);
fixup(entity, included);
return nullable
? default
: throw new InvalidOperationException(
RelationalStrings.JsonRequiredEntityWithNullJson(typeof(TEntity).Name));
}

var manager = new Utf8JsonReaderManager(jsonReaderData);

if (manager.CurrentReader.TokenType == JsonTokenType.Null)
{
return nullable
? default
: throw new InvalidOperationException(
RelationalStrings.JsonRequiredEntityWithNullJson(typeof(TEntity).Name));
}

if (manager.CurrentReader.TokenType == JsonTokenType.StartObject)
{
manager.CaptureState();
var result = shaper(queryContext, keyPropertyValues, jsonReaderData);

return result;
}

// TODO: cleanup & add strings when all is ready
throw new InvalidOperationException("Invalid token type: " + manager.CurrentReader.TokenType.ToString());
}

private static void IncludeJsonEntityCollection<TIncludingEntity, TIncludedCollectionElement>(
private static TResult? MaterializeJsonEntityCollection<TEntity, TResult>(
QueryContext queryContext,
JsonElement? jsonElement,
object[] keyPropertyValues,
TIncludingEntity entity,
Func<QueryContext, object[], JsonElement, TIncludedCollectionElement> innerShaper,
Action<TIncludingEntity, TIncludedCollectionElement> fixup)
where TIncludingEntity : class
where TIncludedCollectionElement : class
JsonReaderData jsonReaderData,
INavigationBase navigation,
Func<QueryContext, object[], JsonReaderData, TEntity> innerShaper)
where TEntity : class
where TResult : ICollection<TEntity>
{
if (jsonElement.HasValue && jsonElement.Value.ValueKind != JsonValueKind.Null)
if (jsonReaderData == null)
{
return default;
}

var manager = new Utf8JsonReaderManager(jsonReaderData);
var tokenType = manager.CurrentReader.TokenType;

if (tokenType == JsonTokenType.Null)
{
return default;
}

if (tokenType == JsonTokenType.StartArray)
{
var collectionAccessor = navigation.GetCollectionAccessor();
var result = (TResult)collectionAccessor!.Create();

var newKeyPropertyValues = new object[keyPropertyValues.Length + 1];
Array.Copy(keyPropertyValues, newKeyPropertyValues, keyPropertyValues.Length);

tokenType = manager.MoveNext();

var i = 0;
foreach (var jsonArrayElement in jsonElement.Value.EnumerateArray())
while (tokenType != JsonTokenType.EndArray)
{
newKeyPropertyValues[^1] = ++i;

var resultElement = innerShaper(queryContext, newKeyPropertyValues, jsonArrayElement);
if (tokenType == JsonTokenType.StartObject)
{
manager.CaptureState();
var entity = innerShaper(queryContext, newKeyPropertyValues, jsonReaderData);
result.Add(entity);
manager = new Utf8JsonReaderManager(manager.Data);

fixup(entity, resultElement);
if (manager.CurrentReader.TokenType != JsonTokenType.EndObject)
{
// TODO: cleanup & add strings when all is ready
throw new InvalidOperationException("expecting end object, got: " + tokenType.ToString());
}

tokenType = manager.MoveNext();
}
}

manager.CaptureState();

return result;
}

// TODO: cleanup & add strings when all is ready
throw new InvalidOperationException("Expecting StartArray token, got: " + tokenType.ToString());
}

private static TEntity? MaterializeJsonEntity<TEntity>(
private static void IncludeJsonEntityReference<TIncludingEntity, TIncludedEntity>(
QueryContext queryContext,
JsonElement? jsonElement,
object[] keyPropertyValues,
bool nullable,
Func<QueryContext, object[], JsonElement, TEntity> shaper)
where TEntity : class
JsonReaderData jsonReaderData,
TIncludingEntity entity,
Func<QueryContext, object[], JsonReaderData, TIncludedEntity> innerShaper,
Action<TIncludingEntity, TIncludedEntity> fixup)
where TIncludingEntity : class
where TIncludedEntity : class
{
if (jsonElement.HasValue && jsonElement.Value.ValueKind != JsonValueKind.Null)
if (jsonReaderData == null)
{
var result = shaper(queryContext, keyPropertyValues, jsonElement.Value);

return result;
}

if (nullable)
{
return default;
return;
}

throw new InvalidOperationException(
RelationalStrings.JsonRequiredEntityWithNullJson(typeof(TEntity).Name));
var included = innerShaper(queryContext, keyPropertyValues, jsonReaderData);
fixup(entity, included);
}

private static TResult? MaterializeJsonEntityCollection<TEntity, TResult>(
private static void IncludeJsonEntityCollection<TIncludingEntity, TIncludedCollectionElement>(
QueryContext queryContext,
JsonElement? jsonElement,
object[] keyPropertyValues,
INavigationBase navigation,
Func<QueryContext, object[], JsonElement, TEntity> innerShaper)
where TEntity : class
where TResult : ICollection<TEntity>
JsonReaderData jsonReaderData,
TIncludingEntity entity,
Func<QueryContext, object[], JsonReaderData, TIncludedCollectionElement> innerShaper,
Action<TIncludingEntity, TIncludedCollectionElement> fixup)
where TIncludingEntity : class
where TIncludedCollectionElement : class
{
if (jsonElement.HasValue && jsonElement.Value.ValueKind != JsonValueKind.Null)
if (jsonReaderData == null)
{
var collectionAccessor = navigation.GetCollectionAccessor();
var result = (TResult)collectionAccessor!.Create();
return;
}

var manager = new Utf8JsonReaderManager(jsonReaderData);
var tokenType = manager.CurrentReader.TokenType;
if (tokenType == JsonTokenType.StartArray)
{
var newKeyPropertyValues = new object[keyPropertyValues.Length + 1];
Array.Copy(keyPropertyValues, newKeyPropertyValues, keyPropertyValues.Length);

tokenType = manager.MoveNext();

var i = 0;
foreach (var jsonArrayElement in jsonElement.Value.EnumerateArray())
while (tokenType != JsonTokenType.EndArray)
{
newKeyPropertyValues[^1] = ++i;

var resultElement = innerShaper(queryContext, newKeyPropertyValues, jsonArrayElement);
if (tokenType == JsonTokenType.StartObject)
{
manager.CaptureState();
var resultElement = innerShaper(queryContext, newKeyPropertyValues, jsonReaderData);
fixup(entity, resultElement);
manager = new Utf8JsonReaderManager(manager.Data);

if (manager.CurrentReader.TokenType != JsonTokenType.EndObject)
{
// TODO: cleanup & add strings when all is ready
throw new InvalidOperationException("expecting end object, got: " + tokenType.ToString());
}

result.Add(resultElement);
tokenType = manager.MoveNext();
}
}

return result;
manager.CaptureState();
}
else
{
// TODO: cleanup & add strings when all is ready
throw new InvalidOperationException("Expecting StartArray token, got: " + tokenType.ToString());
}

return default;
}

private static async Task TaskAwaiter(Func<Task>[] taskFactories)
Expand Down
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