Table ID is an opaque identifier that is only meaningful to the MV store.
Each checkpointed MVCC table corresponds to a single B-tree on the pager,
which naturally has a root page.
We cannot use root page as the MVCC table ID directly because:
- We assign table IDs during MVCC commit, but
- we commit pages to the pager only during checkpoint
which means the root page is not easily knowable ahead of time.
Hence, we:
- store the mapping between table id and btree rootpage
- sqlite_schema rows will have a negative rootpage column if the
table has not been checkpointed yet.
MVCC is like the annoying younger cousin (I know because I was him) that
needs to be treated differently. MVCC requires us to use root_pages that
might not be allocated yet, and the plan is to use negative root_pages
for that case. Therefore, we need i64 in order to fit this change.
This patch improves the encryption module:
1. Previously, we did not use the first 100 bytes in encryption. This
patch uses that portion as associated data, for protection against
tampering and corruption
2. Once the page 1 encrypted, on disk we store a special Turso header
(the first 16 bytes). During decryption we replace this with standard
SQLite's header (`"SQLite format 3\000"`). So that the upper layers (B
Tree or in Sync APIs) operate on the existing SQLite page expectations.
The format is:
```
/// Turso Header (16 bytes)
/// ┌─────────┬───────┬────────┬──────────────────┐
/// │ │ │ │ │
/// │ Turso │Version│ Cipher │ Unused │
/// │ (5) │ (1) │ (1) │ (9 bytes) │
/// │ │ │ │ │
/// └─────────┴───────┴────────┴──────────────────┘
/// 0-4 5 6 7-15
///
/// Standard SQLite Header: "SQLite format 3\0" (16 bytes)
/// ↓
/// Turso Encrypted Header: "Turso" + Version + Cipher ID + Unused
```
Reviewed-by: Nikita Sivukhin (@sivukhin)
Reviewed-by: bit-aloo (@Shourya742)
Closes#3358
against tampering and corruption.
Previously, we did not use the first 100 bytes in encryption
machinery. This patch changes that and uses that data as
associated data. So in case the header is corrupted or
tampered with, the decryption will fail.
TransitionResult is an internal implementation detail that tells
an invocation of StateMachine::step() to continue looping, but it
is of no use to other callers.
For this reason, just return an IOResult from StateMachine::step()
which simplifies the result handling.
This PR adds support for partial indexes, e.g. `CREATE INDEX` with a
provided predicate
```sql
CREATE UNIQUE INDEX idx_expensive ON products(sku) where price > 100;
```
The PR does not yet implement support for using the partial indexes in
the optimizer.
Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>
Closes#3228
