Open an in-memory database on the web

[xvrh]

Can we open an in-memory database on the web?

Would be great to be able to write:

  final db = SqliteDatabase(
    path: ':memory:',
    options: SqliteOptions(webSqliteOptions: WebSqliteOptions.defaults()),

Currently it seems to create an IndexedDB named :memory:

I also tried something like

final sqlite = await WasmSqlite3.loadFromUrl(
      Uri.parse('sqlite3.wasm'));
sqlite.registerVirtualFileSystem(InMemoryFileSystem(), makeDefault: true);
var db = sqlite.openInMemory();

But this gives a CommonDatabase and I don't know how to convert it to a SqliteDatabase.

Any help would be appreciated.

[simolus3]

But this gives a CommonDatabase and I don't know how to convert it to a SqliteDatabase.

Doing SqliteDatabase.singleConnection(SqliteConnection.synchronousWrapper(db)) should work.

I don't think we really have support for in-memory databases outside of singleConnection. :memory: would likely not work on native platforms either (you'd get an in-memory database, but since sqlite_async opens multiple connections for a writer + read pool, most of what this library has to offer wouldn't be available).

[andynewman10]

But this gives a CommonDatabase and I don't know how to convert it to a SqliteDatabase.

Doing SqliteDatabase.singleConnection(SqliteConnection.synchronousWrapper(db)) should work.

I tested with a database created using a database file sheltered in an InMemoryFileSystem instance (that is, not using openInMemory) and this works great, on both web and mobile.

Can you confirm, however, that queries will indeed be processed asynchronously in this case? I understand your worker thread has access to the main thread-created memory filesystem just like it has access to, eg., IndexedDB database files, right?

I don't think we really have support for in-memory databases outside of singleConnection. :memory: would likely not work on native platforms either (you'd get an in-memory database, but since sqlite_async opens multiple connections for a writer + read pool, most of what this library has to offer wouldn't be available).

[simolus3]

Ah, now I understand your other issue too :D

Can you confirm, however, that queries will indeed be processed asynchronously in this case?

No, SqliteConnection.synchronousWrapper runs queries synchronously. But typically for in-memory databases you don't really need asynchronous access, or are you running compute-heavy queries there?

[andynewman10]

Ah, now I understand your other issue too :D

Can you confirm, however, that queries will indeed be processed asynchronously in this case?

No, SqliteConnection.synchronousWrapper runs queries synchronously. But typically for in-memory databases you don't really need asynchronous access, or are you running compute-heavy queries there?

Yes, I am indeed running compute-heavy queries that are challenging even in a pure memory setting.