simolus3
commented
3 years ago Do you compile it yourself? If yes, then maybe it is possible to set a compiler flag so that this does not happen.
Yes, we use a "custom" (some compile-time options set) sqlite, the definition is here. I added a compile-time option to use an in-memory store for temporary operations because of #667. That fixed a problem with non-small queries, but apparently it's not enough for big databases.
this pragma is deprecated
Fortunately, the underlying sqlite3_temp_directory variable isn't deprecated and we can expose it from package:sqlite3. The documentation warns about using it, but since the default behavior is broken on Android we're pretty much forced to set that variable.
I've just published sqlite3: 0.1.7, in which you can set the temporary directory used by sqlite:
import 'package:sqlite3/sqlite3.dart';
// Do this once, before opening a database
Future<void> init() async {
if (Platform.isAndroid) {
final cachebase = (await getTemporaryDirectory()).path;
sqlite3.tempDirectory = cachebase;
}
}You might need this one as well:
VmDatabase(
setup: (database) {
if (Platform.isAndroid) database.execute('PRAGMA temp_store = FILE');
}
);It's hard to make this an "it just works" solution since getTemporaryDirectory() is Flutter-only. I could make it a utility function in sqlite3_flutter_libs if this improves the situation.
knaeckeKami
I'm running into an issue that occurs with complex queries on big-ish (~50mb) databases on Android using the ffi/sqlite3 library.
When running the query, I get an error code 6410 (SQLITE_IOERR_GETTEMPPATH):
From what I researched, this seems to happen that the intermediate results for SQLite were too big to handle them in-memory, but SQLite could not find a temporary directory to store the result.
Luckily, I found a fix/workaround: According to https://stackoverflow.com/questions/44766917/sql-logic-error-only-when-querying-on-android , this can be fixed by setting a pragma:
I'm a little bit concerned though, since this pragma is deprecated according to https://www.sqlite.org/pragma.html#pragma_temp_store_directory
I'm just wondering if we can do anything to have this 'just work' for other users? Where do you get the sqlite library, that is shipped with sqlite3_flutter_libs, from? Do you compile it yourself? If yes, then maybe it is possible to set a compiler flag so that this does not happen.