The DX is right now pretty terrible:
```
penberg@vonneumann turso % cargo run -- hello.db
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.15s
Running `target/debug/tursodb hello.db`
Turso v0.4.0-pre.18
Enter ".help" for usage hints.
Did you know that Turso supports live materialized views? Type .manual materialized-views to learn more.
This software is in BETA, use caution with production data and ensure you have backups.
turso> PRAGMA journal_mode = 'experimental_mvcc';
× Invalid argument supplied: MVCC is not enabled. Enable it with `--experimental-mvcc` flag in the CLI or by setting the MVCC option in `DatabaseOpts`
turso>
```
To add insult to the injury, many SDKs don't even have a way to enable
MVCC via database options. Therefore, let's remove the flag altogether.
Makes it easier to test the feature:
```
$ cargo run -- --experimental-indexes
Limbo v0.0.22
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database
limbo> CREATE TABLE t(x);
limbo> CREATE INDEX t_idx ON t(x);
limbo> DROP INDEX t_idx;
```
OwnedValue has become a powerhouse of madness, mainly because I decided
to do it like that when I first introduced AggContext. I decided it was
enough and I introduced a `Register` struct that contains `OwnedValue`,
`Record` and `Aggregation`, this way we don't use `OwnedValue` for
everything make everyone's life harder.
This is the next step towards making ImmutableRecords the default
because I want to remove unnecessary allocations. Right now we clone
OwnedValues when we generate a record more than needed.
We currently have two value types, `Value` and `OwnedValue`. The
original thinking was that `Value` is external type and `OwnedValue` is
internal type. However, this just results in unnecessary transformation
between the types as data crosses the Limbo library boundary.
Let's just follow SQLite here and consolidate on a single value type
(where `sqlite3_value` is just an alias for the internal `Mem` type).
The way this will eventually work is that we can have bunch of
pre-allocated `OwnedValue` objects in `ProgramState` and basically
return a reference to them all the way to the application itself, which
extracts the actual value.
Move result row to `ProgramState` to mimic what SQLite does where `Vdbe`
struct has a `pResultRow` member. This makes it easier to deal with result
lifetime, but more importantly, eventually lazily parse values at the edges of
the API.
## Purpose of this PR
- Implement `close()` method for `LimboStatement`(+`JDBC4Statement`) and
`LimboResultSet`(+ `JDBC4ResultSet`)
## Changes
- Add `consumeAll` method in `LimboResultSet`
- Implement `close()` methods
- Because `JDBC4Statement` has longer lifecycle in compared to
`LimboStatement`, we manage different `close` fields(`LimboStatement` is
created when first `execute` method is called on `JDBC4Statemenet`)
## Reference
- [Issue](https://github.com/tursodatabase/limbo/issues/615)
Closes#799
