Class PageCacheEventCodec

Namespace

Typhon.Profiler

Assembly

Typhon.Profiler.dll

Shared wire codec for all five page-cache event kinds. Every kind writes a 4-byte "primary value" slot (FilePageIndex for most, PageCount for Flush) plus a 1-byte optMask, plus optional trailing fields keyed by the mask bits.

public static class PageCacheEventCodec

Inheritance

object

PageCacheEventCodec

Inherited Members

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Remarks

Phase 5 wire-additive extension: OptDirtyBit (0x02) appends one trailing byte for the PageEvicted dirty flag (1 = displaced page was dirty, 0 = clean). Old decoders see an unknown mask bit and stop reading at the cursor they expect; the record-size header in the common header tells them where the next record begins, so wire compatibility is preserved.

Fields

OptDirtyBit

Optional-mask bit 1 (Phase 5) — trailing 1-byte dirtyBit on PageEvicted.

public const byte OptDirtyBit = 2

Field Value

byte

OptPageCount

Optional-mask bit 0 — PageCount on DiskWrite (contiguous run length).

public const byte OptPageCount = 1

Field Value

byte

Methods

ComputeSize(TraceEventKind, bool, byte, ushort)

Total on-wire record size in bytes for a page-cache event, accounting for the optional fields the mask selects.

public static int ComputeSize(TraceEventKind kind, bool hasTraceContext, byte optMask, ushort sourceLocationId = 0)

Parameters

kind TraceEventKind

Event kind (does not affect size; carried for symmetry with the encoder).

hasTraceContext bool

Whether a 16-byte trace context is included in the span header.

optMask byte

Optional-field mask — see OptPageCount / OptDirtyBit.

sourceLocationId ushort

Non-zero adds a 2-byte source-location id to the header.

Returns

int

Decode(ReadOnlySpan<byte>)

Decode any page-cache span record into structured form. The event kind is read from the common header.

public static PageCacheEventData Decode(ReadOnlySpan<byte> source)

Parameters

source ReadOnlySpan<byte>

Returns

PageCacheEventData