Class PagedMMFOptions

Namespace

Typhon.Engine

Assembly

Typhon.Engine.dll

Configuration for a Typhon.Engine.Internals.PagedMMF / Typhon.Engine.Internals.ManagedPagedMMF store: which database (name + directory), how large the page cache is, and a couple of diagnostics. A Typhon database is a single on-disk bundle directory (BundleDirectory); these options locate and size it.

public class PagedMMFOptions

Inheritance

object

PagedMMFOptions

Inherited Members

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Constructors

PagedMMFOptions()

public PagedMMFOptions()

Fields

DatabaseNameMaxUtf8Size

Maximum length, in UTF-8 bytes, allowed for DatabaseName and DatabaseFileName.

public const int DatabaseNameMaxUtf8Size = 63

Field Value

int

DefaultCacheSizeBytes

The default DatabaseCacheSize in bytes (256 MiB) — the value used when it is not set explicitly.

public const ulong DefaultCacheSizeBytes = 268435456

Field Value

ulong

MinimumCacheSizeBytes

The minimum permitted DatabaseCacheSize in bytes (8 MiB). Values below this fail validation.

public const ulong MinimumCacheSizeBytes = 8388608

Field Value

ulong

PageSizeBytes

The page size in bytes (8 KiB). DatabaseCacheSize must be a multiple of this.

public const int PageSizeBytes = 8192

Field Value

int

Properties

BundleDirectory

The database bundle directory — {DatabaseDirectory}/{DatabaseName}.typhon. A Typhon database is this single directory; the paged data file (data), the single-writer lock (db.lock), and the WAL segment directory (wal/) all live inside it. See claude/design/Storage/typhon-bundle-format.md.

public string BundleDirectory { get; }

Property Value

string

DatabaseAbsoluteDirectory

The absolute form of DatabaseDirectory.

public string DatabaseAbsoluteDirectory { get; }

Property Value

string

DatabaseCacheSize

Page-cache size, in bytes. Must be a multiple of PageSizeBytes, at least MinimumCacheSizeBytes, and at most 4 GiB. Default: DefaultCacheSizeBytes (256 MiB). The cache is a GCHandle-pinned byte array, so size it for one primary engine per process; a workload whose transaction working set exceeds the cache hits PageCacheBackpressureTimeoutException. Prefer the fluent TyphonOptions.PageCacheSize(...) to set it.

public ulong DatabaseCacheSize { get; set; }

Property Value

ulong

DatabaseDirectory

Directory that contains the database bundle. Default: the current working directory.

public string DatabaseDirectory { get; set; }

Property Value

string

DatabaseFileName

Configured database file-name prefix; falls back to DatabaseName when unset. Subject to the same character and length rules.

public string DatabaseFileName { get; set; }

Property Value

string

DatabaseName

The database name — also the stem of the bundle directory (BundleDirectory). Must match ^[A-Za-z0-9_-]+$ and fit within DatabaseNameMaxUtf8Size UTF-8 bytes. Default: TyphonDB.

public string DatabaseName { get; set; }

Property Value

string

IsValid

Whether the current configuration passes validation (name, directory, and cache-size rules). true when every rule holds.

public bool IsValid { get; }

Property Value

bool

PagesDebugPattern

When true, fills newly-allocated pages with a recognizable debug pattern (development/testing). Default false.

public bool PagesDebugPattern { get; set; }

Property Value

bool

Methods

EnsureFileDeleted()

Deletes the entire database bundle directory (BundleDirectory) — data file, lock, and WAL. A Typhon database is one directory, so "delete the database" is a single recursive directory delete. Must only be called when the database is closed: an open data handle would block the recursive delete (the throw is swallowed, potentially leaving a half-deleted bundle).

public void EnsureFileDeleted()