THPDFMappedFileStatistics Record

Reports configuration, geometry, mapping, cache, and transfer telemetry gathered by the memory-mapped file source during a load

Declaration

THPDFMappedFileStatistics= record
  FileSize: Int64;
  ConfiguredWindowSize: Int64;
  ConfiguredCacheWindowCount: Integer;
  WindowSize: Int64;
  CacheWindowCount: Integer;
  MappedByteLimit: Int64;
  CurrentMappedBytes: Int64;
  PeakMappedBytes: Int64;
  GeometryChangeCount: Int64;
  SequentialReadCalls: Int64;
  RandomReadCalls: Int64;
  AdaptiveGeometry: Boolean;
  SequentialGeometryActive: Boolean;
  RandomGeometryActive: Boolean;
  ReadCalls: Int64;
  BytesRead: Int64;
  MapCount: Int64;
  CacheHits: Int64;
  FallbackReadCalls: Int64;
  FallbackBytes: Int64;
  DirectTransferCalls: Int64;
  DirectTransferBytes: Int64;
end;

Unit

HPDFObjs

Fields

Field	Purpose
`FileSize`	Size of the mapped source file in bytes
`ConfiguredWindowSize`	Window size as configured through `LocalFileMappingWindowSize`
`ConfiguredCacheWindowCount`	Resident window count as configured through `LocalFileMappingCacheWindows`
`WindowSize`	Window size actually in effect for this source
`CacheWindowCount`	Number of windows currently held by the window cache
`MappedByteLimit`	Upper bound on bytes the source keeps mapped at once
`CurrentMappedBytes`	Bytes currently mapped
`PeakMappedBytes`	High-water mark of mapped bytes over the load
`GeometryChangeCount`	Times the adaptive geometry switched the window layout
`SequentialReadCalls`	Read requests classified as sequential
`RandomReadCalls`	Read requests classified as random access
`AdaptiveGeometry`	True when adaptive geometry selection is enabled for the source
`SequentialGeometryActive`	True while the sequential window geometry is active
`RandomGeometryActive`	True while the random-access window geometry is active
`ReadCalls`	Total read requests served through the mapped source
`BytesRead`	Total bytes delivered by those reads
`MapCount`	Times a file view was mapped into a window
`CacheHits`	Reads satisfied by an already resident window
`FallbackReadCalls`	Reads that fell back to plain file reads outside the window cache
`FallbackBytes`	Bytes delivered by fallback reads
`DirectTransferCalls`	Direct stream-to-stream transfers that bypass the window cache
`DirectTransferBytes`	Bytes moved by direct transfers

Usage notes

Read the record with THotPDF.GetLastMappedFileStatistics, which returns True only when the last load actually used memory mapping
Tune the geometry with LocalFileMappingWindowSize, LocalFileMappingCacheWindows, and LocalFileMappingAdaptiveGeometry before loading
SequentialGeometryActive and RandomGeometryActive are mutually exclusive snapshots of the current mode

THPDFMappedFileStatistics Record

Declaration

Unit

Fields

Usage notes

Related APIs