Class ComponentTable

Namespace

Typhon.Engine

Assembly

Typhon.Engine.dll

Stores all instances of a single component type with MVCC revision tracking.

public class ComponentTable : ResourceNode, IResource, IDisposable, IMetricSource, IDebugPropertiesProvider

Inheritance

object

ResourceNode

ComponentTable

Implements

IResource

IDisposable

IMetricSource

IDebugPropertiesProvider

Inherited Members

ResourceNode.RegisterChild(IResource)

ResourceNode.RemoveChild(IResource)

ResourceNode.Dispose()

ResourceNode.Id

ResourceNode.Name

ResourceNode.Type

ResourceNode.Parent

ResourceNode.Children

ResourceNode.CreatedAt

ResourceNode.Owner

ResourceNode.ExhaustionPolicy

ResourceNode.DisposeWithParent

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Extension Methods

ResourceExtensions.FindAll(IResource, Func<IResource, bool>)

ResourceExtensions.FindByPath(IResource, string, string)

ResourceExtensions.FindFirst(IResource, Func<IResource, bool>)

ResourceExtensions.GetAncestors(IResource)

ResourceExtensions.GetDepth(IResource)

ResourceExtensions.GetDescendantCount(IResource)

ResourceExtensions.GetDescendants(IResource)

ResourceExtensions.GetMetricSources(IResource)

ResourceExtensions.GetPath(IResource, string)

ResourceExtensions.IsAncestorOf(IResource, IResource)

ResourceExtensions.IsDescendantOf(IResource, IResource)

Remarks

ComponentTable registers as a child of its owning DatabaseEngine in the resource tree. Segments (ComponentSegment, CompRevTableSegment, etc.) are NOT registered as children — they follow the "Owner Aggregates" pattern where ComponentTable will aggregate their metrics.

Constructors

ComponentTable(DatabaseEngine, DBComponentDefinition, IResource, StorageMode, ExhaustionPolicy, ChangeSet)

Creates a new (empty) component table, allocating its data, revision, and index segments. For Transient the segments are heap-backed and no MVCC revision chain is allocated.

public ComponentTable(DatabaseEngine dbe, DBComponentDefinition definition, IResource parent, StorageMode storageMode = StorageMode.Versioned, ExhaustionPolicy exhaustionPolicy = ExhaustionPolicy.None, ChangeSet changeSet = null)

Parameters

dbe DatabaseEngine

Owning database engine.

definition DBComponentDefinition

Schema definition of the component type stored here.

parent IResource

Resource-tree parent (the owning DatabaseEngine).

storageMode StorageMode

Storage discipline: Versioned (default, MVCC), SingleVersion, or Transient.

exhaustionPolicy ExhaustionPolicy

Resource-exhaustion policy forwarded to the base ResourceNode.

changeSet ChangeSet

Change set threading segment-growth dirty marks through the allocation; may be null.

Properties

CompRevTableSegment

Segment holding the MVCC revision chains. Non-null only for Versioned storage.

public ChunkBasedSegment<PersistentStore> CompRevTableSegment { get; }

Property Value

ChunkBasedSegment<PersistentStore>

ComponentSegment

Segment holding the component data chunks (the field payloads). Null in Transient mode.

public ChunkBasedSegment<PersistentStore> ComponentSegment { get; }

Property Value

ChunkBasedSegment<PersistentStore>

ComponentStorageSize

Size in bytes of a single component's field payload (excludes MVCC and index overhead).

public int ComponentStorageSize { get; }

Property Value

int

Count

Surfaces the entity count as Count so the Workbench can render a live badge on the ComponentTable tree node without a second round-trip.

public override int? Count { get; }

Property Value

int?

DefaultIndexSegment

Segment backing the primary-key B+Tree and every non-String64 secondary index.

public ChunkBasedSegment<PersistentStore> DefaultIndexSegment { get; }

Property Value

ChunkBasedSegment<PersistentStore>

Definition

Schema definition (fields, indexes, layout) of the component type stored in this table.

public DBComponentDefinition Definition { get; }

Property Value

DBComponentDefinition

Discipline

Default durability discipline for this component, resolved from [Component(DefaultDiscipline=…)]. Only consulted for SingleVersion; a transaction writing a Commit component is committed-durable for all of its writes (CM-02).

public DurabilityDiscipline Discipline { get; }

Property Value

DurabilityDiscipline

EstimatedEntityCount

Estimated total entity count. Sums EntityMap entry counts across archetypes that include this component.

public int EstimatedEntityCount { get; }

Property Value

int

Flags

Optional storage features enabled on this table (see ComponentTableFlags).

public ComponentTableFlags Flags { get; }

Property Value

ComponentTableFlags

HasCollections

true when the component declares at least one collection-typed field (HasCollections is set).

public bool HasCollections { get; }

Property Value

bool

StorageMode

Storage discipline for this component, fixed at construction: Versioned (MVCC revision chains), SingleVersion (in-place, tick-boundary maintenance), or Transient (heap-backed, not persisted).

public StorageMode StorageMode { get; }

Property Value

StorageMode

String64IndexSegment

Segment backing the String64-keyed secondary indexes.

public ChunkBasedSegment<PersistentStore> String64IndexSegment { get; }

Property Value

ChunkBasedSegment<PersistentStore>

TailIndexSegment

Segment backing the version-history tail for AllowMultiple secondary indexes. Null when the component has no multi-value index.

public ChunkBasedSegment<PersistentStore> TailIndexSegment { get; }

Property Value

ChunkBasedSegment<PersistentStore>

Methods

Dispose(bool)

Releases the table's owned persistent and transient segments (and the heap-backed transient stores). Idempotent — a second call is a no-op.

protected override void Dispose(bool disposing)

Parameters

disposing bool

true when disposing deterministically; false when running from the finalizer.

GetDebugProperties()

Gets detailed debug properties for diagnostic drill-down.

public IReadOnlyDictionary<string, object> GetDebugProperties()

Returns

IReadOnlyDictionary<string, object>

A dictionary of property names to values. Values should be primitives, strings, or types that have meaningful ToString() implementations.

Remarks

This method may allocate (returns new dictionary) since it's called infrequently. Callers should cache results if needed across multiple accesses.

Property naming convention: Use dot-notation for nested concepts (e.g., "ComponentSegment.Allocated", "Contention.MaxWaitUs").

ReadMetrics(IMetricWriter)

Writes current metric values to the provided writer.

public void ReadMetrics(IMetricWriter writer)

Parameters

writer IMetricWriter

The writer to report metrics to. Call one or more Write* methods.

Remarks

Called during snapshot collection (every 1-5 seconds). Implementations should:

• Read fields and write to writer quickly (target < 100ns)
• Not allocate (no new objects, no LINQ, no string formatting)
• Not acquire locks (read fields directly, accept slight inconsistency)
• Not call other IMetricSource.ReadMetrics() — the graph handles recursion

Only report metric kinds that are relevant to this resource. For example, a TransactionPool might only report Capacity and Throughput, not Memory or DiskIO.

ResetPeaks()

Resets all high-water mark metrics (PeakBytes, MaxWaitUs, MaxUs, etc.) to current values.

public void ResetPeaks()

Remarks

Called by ResetAllPeaks() to enable windowed peak measurements. After displaying or exporting peak values, this method resets them so subsequent peaks represent new maxima since the last reset.

If this node has no high-water marks, implement as an empty method. Plain writes are sufficient — snapshots are taken every 1-5 seconds, so eventual visibility is acceptable.