Devolutions.Ahtola.Core 0.1.0

Ahtola .NET

An experimental pure managed (C#) port of Turso’s SQLite-compatible database engine, with ADO.NET and EF Core providers.

⚠️ Experimental project. Ahtola is a research / prototype engine and is not production-ready. For production .NET workloads, use the official bindings to the original Turso Rust core at tursodatabase/turso.

Ahtola is a C# engine that reads and writes SQLite’s on-disk format directly — automatically vibe-ported from Turso’s Rust core, as a fun experiment. It is not a binding over native SQLite or over any Rust core — no native companion, P/Invoke SDK, or Rust toolchain is required to restore, build, pack, or run.

• Install
• Quick start
• PowerShell module
• What this is good for
• Important limits
• Building from source

Install

dotnet add package Devolutions.Ahtola.Data.Sqlite
# optional EF Core provider (9.x on net8/net9, 10.x on net10):
dotnet add package Devolutions.Ahtola.EntityFrameworkCore.Sqlite

Targets: net8.0, net9.0, net10.0. No net48 / .NET Framework assets.

Quick start

SQLite-compatible facade (drop-in using swap from Microsoft.Data.Sqlite):

using Ahtola.Data.Sqlite;

using var connection = new SqliteConnection("Data Source=app.db");
connection.Open();
connection.ExecuteNonQuery("CREATE TABLE t(a INTEGER, b TEXT)");
connection.ExecuteNonQuery("INSERT INTO t VALUES (1, 'hello')");

using var command = connection.CreateCommand();
command.CommandText = "SELECT a, b FROM t";
using var reader = command.ExecuteReader();
while (reader.Read())
    Console.WriteLine($"{reader.GetInt32(0)} {reader.GetString(1)}");

Ahtola types (same package):

using Ahtola;

using var connection = new AhtolaConnection("Data Source=:memory:");
connection.Open();
connection.ExecuteNonQuery("CREATE TABLE t(a, b)");
// AhtolaConnection, AhtolaCommand, AhtolaParameter, AhtolaFactory.Instance, …

EF Core:

options.UseAhtola("Data Source=app.db");

Common connection-string keywords: Data Source, Mode, Cache, Pooling, Foreign Keys, Default Timeout / Command Timeout, Foreign Read Only, DateTimeKind, BinaryGUID, Password (passphrase → AES-256-GCM), or Encryption Cipher + Encryption Key (hex AES-128/256-GCM). Default local provider is managed-only.

Standard SQLite files

Managed open of unencrypted SQLite databases created by System.Data.SQLite / Microsoft.Data.Sqlite / native sqlite3 is supported (Data Source=path only; no special flags). Ahtola is byte-compatible with the on-disk format for normal read/write workloads.

File encryption (not SEE / SQLCipher)

Encryption is layered so new recipes can be added without rewriting the pager:

Built-in scheme Ahtola.Password.v1: PBKDF2-HMAC-SHA256, fixed domain salt Ahtola.Password.v1, 210k iterations to AES-256-GCM. Changing KDF bytes requires a new scheme id (via AhtolaPassphraseSchemes.Register or a future built-in), never a silent change to v1.

Do not combine Password and Encryption Key. Legacy SEE/SQLCipher files are not opened by passphrase schemes — use a dedicated IPageCodec or export/recreate under Ahtola password / plain SQLite.

Wrong/missing password failures include the phrase file is encrypted or is not a database for SDS-shaped detection.

PowerShell module

Devolutions.Ahtola.Sqlite is a binary PowerShell module that exposes the Ahtola engine through *-AhtolaSqlite* cmdlets. Its implementation is ported from synedgy.PSSqlite and re-backed onto Ahtola.Data.Sqlite instead of Microsoft.Data.Sqlite / SQLitePCLRaw — so importing it pulls in no native SQLite assets. The public command noun is AhtolaSqlite to avoid collisions with other SQLite PowerShell modules.

Requires PowerShell 7.4+. Windows PowerShell 5.1 is not supported.

Getting the module

It isn't on the PowerShell Gallery yet, so build it from a clone:

./build.ps1 pack-powershell
# -> artifacts/powershell-modules/Devolutions.Ahtola.Sqlite

Then import it from anywhere pwsh 7 runs — no native SQLite binary, no .NET SDK needed at import time:

Import-Module ./artifacts/powershell-modules/Devolutions.Ahtola.Sqlite
Get-Command -Module Devolutions.Ahtola.Sqlite

Model types are available as module-qualified type accelerators, e.g. [Devolutions.Ahtola.Sqlite.SqliteDBConfig].

Cmdlets

New-AhtolaSqliteConnection returns an open connection. Every cmdlet that receives -Connection may open a closed connection but never closes or disposes it. Configuration-driven CRUD creates and disposes its own temporary connection only when -Connection is omitted. -SqliteConnection, -SqliteDBConfig, -TableName, -RowData, and -ClauseData remain compatibility aliases; use -Connection, -Configuration, -Table, -Values, and -Where in new scripts.

Invoke-AhtolaSqliteQuery and the Get-AhtolaSqliteRow family support -As DataTable | DetachedDataReader | DataSet | OrderedDictionary | PSCustomObject; Invoke-AhtolaSqliteQuery additionally supports Scalar and NonQuery. DataReader remains a compatibility alias for DetachedDataReader: it is a materialized snapshot, not a live streaming reader.

Bulk imports fail and roll back their own transaction on the first conflicting row. When passed a caller-owned transaction, the cmdlet uses a savepoint and rolls back only that bulk operation.

Example

# Ad hoc query and default PowerShell-object output
$connection = New-AhtolaSqliteConnection -ConnectionString 'Data Source=:memory:'
Invoke-AhtolaSqliteQuery -Connection $connection `
    -CommandText 'SELECT id, name FROM t WHERE name = $name' `
    -Parameters @{ '$name' = 'b' }

$transaction = Start-AhtolaSqliteTransaction -Connection $connection
Invoke-AhtolaSqliteQuery -Connection $connection -Transaction $transaction `
    -CommandText 'UPDATE Items SET Name = $name WHERE Id = $id' `
    -Parameters @{ '$name' = 'updated'; '$id' = 1 } -As NonQuery
Complete-AhtolaSqliteTransaction -Transaction $transaction

# Portable table export/import infers JSON or CSV from the file extension.
Export-AhtolaSqliteTable -Connection $connection -Table Items -Path ./items.json
Import-AhtolaSqliteTable -Connection $connection -Table Items -Path ./items.csv
$connection | Close-AhtolaSqliteConnection -ClearPool

If you'd rather call the ADO.NET provider from a plain script module instead of using these cmdlets, see samples/PSSqlite.Managed.

What this is good for

• Fully managed local SQLite-format databases with no native assets
• Small-to-moderate workloads, in-process embedding, constrained deployment
• A familiar ADO.NET / MDS-shaped API and an EF Core provider

Important limits

Treat Ahtola as SQLite-compatible, not a full SQLite replacement:

• In-memory working set — tables and intermediate results stay in the process heap; nothing spills to disk. Prefer modest databases and explicit transactions for writes (managed writes are slower than native SQLite and the gap grows with table size).
• Planner — ANALYZE / sqlite_stat1 feed index scoring and limited join cost gates (selective outer for two-table INNER nested loops; equijoin hash build side). Full System-R DP join reordering and multi-index AND intersection are still deferred; OUTER JOIN order stays correctness-preserving. Prefer ORDER BY when order matters (GROUP BY is first-encounter order).
• File-backed platforms — Windows, 64-bit Linux, and macOS. In-memory works everywhere; other platforms (e.g. 32-bit Linux) throw PlatformNotSupportedException on physical open. macOS uses POSIX fcntl(F_SETLK) (process-associated locks, not Linux OFD); multi-engine claims on macOS need host verification.
• Multi-engine files (Stage 6) — physical opens use SQLite main-file SHARED locking (Windows / 64-bit Linux / macOS). Managed and stock SQLite can share the same live WAL database on Windows/Linux (-shm DMS + peer WAL visibility on new statements). Pooling may retain managed handles until Pooling=False or SqliteConnection.ClearAllPools(). PENDING/RESERVED DELETE-mode polish and a Turso binary differential remain optional depth. See docs/wal-interoperability-contract.md.
• Foreign read-only — Mode=ReadOnly;Foreign Read Only=True;Pooling=False can read a DB still held by native SQLite/Turso (e.g. winget index.db) without taking main-file locks.
• MVCC — process-local PRAGMA journal_mode=mvcc + BEGIN CONCURRENT with dual-cursor SELECT/DML routing, logical log, and a checkpoint SM skeleton (PRAGMA wal_checkpoint in MVCC mode). Not cross-process; residual schema- cookie polish and full per-page b-tree checkpoint SM remain open — see docs/mvcc-port-contract.md.
• Not implemented — virtual tables / FTS / R-Tree, loadable extensions, raw sqlite3* handles (Handle is null), AEGIS encryption ciphers, sync engine / CDC, CREATE SEQUENCE, typed-value extensions.
• Native / Sync companions — not shipped. Connection-string paths that need them fail closed. OS P/Invoke in the pager for locks/WAL is intentional engine code, not a Rust SDK binding.
• Remote Hrana — optional pure-managed HTTP /v2/pipeline on AhtolaConnection (tests use a canned server). Not a cloud product surface.

Encryption format v0 uses a fixed 5-byte magic AHTLA, then version and cipher id (AES-GCM page AEAD).

Building from source

Requires the .NET SDK and PowerShell 7+:

./build.ps1 build
./build.ps1 test
./build.ps1 pack              # -> ./artifacts/managed-packages
./build.ps1 pack-powershell   # -> ./artifacts/powershell-modules
./build.ps1 validate-runtime  # packed consumer trim + NativeAOT publish

Contributor details — the full task list, validation gates, conformance suite, and repo layout — live in AGENTS.md and docs/.

License

MIT — see LICENSE.