Currently we can create two guards and unlock one of them and still have
two mutable references to the same data.
By being able to unlock only via guard we prevent unsafe scenarios.
Currently, the test below will pass and shows that we can hold two
mutable references to the same data. After this fix, this would result
in a deadlock (have to remove `lock.unlock()`)
```rust
#[test]
fn two_mutable_reference() {
let lock = SpinLock::new(42);
let guard = lock.lock();
lock.unlock();
let guard2 = lock.lock();
// two mutable references to same data
*guard = 10;
*guard2 = 20;
assert_eq!(*guard, 20);
assert_eq!(*guard2, 20);
}
```
Note: The javascript action failure is unrelated to this PR.
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Closes#1194
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.
Fix memory hogging in MVCC scan cursor #1104
The current scan cursor loads all rowids at once, which blows up memory
on big tables.
Added BucketScanCursor that loads rowids in configurable batches -
better memory usage while keeping decent performance. It's a drop-in
replacement with the same interface.
Also included LazyScanCursor as an alternative that fetches one rowid at
a time, though it's less efficient due to log(n) skipmap lookups for
each row.
BucketScanCursor is the recommended approach for most use cases. WDYT?
Closes#1178
Currently we have a Record, which is a dumb vector of cloned values.
This is incredibly bad for performance as we do not want to clone
objects unless needed. Therefore, let's start by introducing this type
so that any record that has already been serialized will be returned
from btree in the format of a simple payload with reference to payload.
Closes#1176
- Use `CheckpointResult::default()` instead of `CheckpointResult::new()`
- Correct WAL frame header salt and checksum handling
- Ensure frame ID is 1-based and adjust frame offset calculation
- Add `Default` implementation for `CheckpointResult`
- Use random values for WAL header salts
Currently we have a Record, which is a dumb vector of cloned values.
This is incredibly bad for performance as we do not want to clone
objects unless needed. Therefore, let's start by introducing this type
so that any record that has already been serialized will be returned
from btree in the format of a simple payload with reference to payload.
SQLite uses a similar approach for operations where up to 4 JSON objects
are accessed multiple times in a single query.
`SELECT json_extact(a, 'some_path'), json_remove(a, 'some_path')
json_set(a, 'some_path', 'some_value') from t;`
Closes#1163
