Class DataContextCache

Namespace

NextORM.Core

Assembly

nextorm.core.dll

Process-wide caches shared by every context, SQL and in-memory alike. This is the single source of truth for entity metadata, select lists and compiled expression delegates.

public static class DataContextCache

Inheritance

object

DataContextCache

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

The sharing scope of each cache in the code base is stated here explicitly, so that the lifetime of a cache is never a matter of archaeology:

• this class and MapperCache — process-wide;
• InMemoryDataContext.ExpressionsCache — per context instance: its entries embed Expression.Constant(this) and therefore must not be shared;
• DataContext._queryPlanCache — per thread, keyed by QueryPlanCacheKey(ContextType, Plan) so that different providers do not collide.

Properties

CacheSlidingExpiration

Sliding expiration applied to every process-wide cache this class owns. An entry that has not been read within the window is evicted lazily on the next access; every read refreshes it. Zero (the default) disables expiration and adds no per-access cost. Set through DataContextBuilder.UseCacheSlidingExpiration.

public static TimeSpan CacheSlidingExpiration { get; set; }

Property Value

TimeSpan

Exceptions

ArgumentOutOfRangeException

The assigned value is negative.

ExpressionsCache

Compiled expression delegates keyed by ExpressionKey, avoiding recompilation of the same expression tree when it is encountered again.

public static IDictionary<ExpressionKey, Delegate> ExpressionsCache { get; }

Property Value

IDictionary<ExpressionKey, Delegate>

InValuesCache

Compiled accessors that read the captured collection of an in/Contains predicate, keyed by the collection expression's shape. See NextORM.Core.InValuesEvaluator.

public static IDictionary<ExpressionKey, Func<object?, object?>> InValuesCache { get; }

Property Value

IDictionary<ExpressionKey, Func<object, object>>

Metadata

Entity metadata resolved for each CLR type, keyed by that type. Populated lazily on the first From<T> call and reused for the rest of the process.

public static IDictionary<Type, IEntityMetadata> Metadata { get; }

Property Value

IDictionary<Type, IEntityMetadata>

SelectListCache

Cached select lists (the projected columns) of each CLR type, keyed by that type, so the projection is not rebuilt per query.

public static IDictionary<Type, SelectExpression[]> SelectListCache { get; }

Property Value

IDictionary<Type, SelectExpression[]>

Methods

Clear()

Clears every process-wide cache in the engine: the metadata, table-valued-parameter metadata, select-list, expression and in-values caches owned by this class, the compiled row-mapper cache, the projection-alias and FROM caches, the compiled JoinInto identity-selector cache, and the thread-local plan cache. The next query rebuilds whatever it needs.

public static void Clear()

Remarks

The plan cache is [ThreadStatic], so a plan created on another thread is dropped lazily when that thread next touches the cache (the store is invalidated through a process-wide generation counter). A context's per-instance caches (for example InMemoryDataContext.CommandIndex) are not reached; clear those with PurgeQueryCache(). The context-owned JSON row-writer caches are invalidated here through the NextORM.Core.DataContextCache.JsonRowWriterCacheGeneration counter: each of them drops its entries lazily on its next lookup.