* `write` was returning `true` even though it shouldn't because it
should return `false` in case it was already acquired.
* `read` theoritically can increase `nread` after another thread calls
`unlock` between first lock load and increase of `nread`. So it looks
something like this:
1. THREAD 1: read()
2. THREAD 2: get lock = `SHARED_LOCK`
3. THREAD 1: unlock -> lock is now `NO_LOCK`
4. THREAD 2: increase nread, return true.
This is obviously wrong because `nreads` will be ` > 0 ` but `lock`
is `NO_LOCK`
Closes#1676
This commit ensures that the metadata in the database header and the pointer map pages allocated are correctly persisted to the page cache. This was not being done earlier.
This commit introduces AUTOVACUUM to Limbo. It introduces the concept of ptrmap pages and also adds some additional instructions that are required to make AUTOVACUUM PRAGMA work
Closes#1622
I did an A/B test between SQLite and Limbo and they can restart the db
from each other, indicating that there isn't something very wrong with
our file format. Turns out it was with our reset logic without
truncating the file. I assumed it's safe to don't reset if we're in
`PASSIVE` mode, given the
[docs](https://www.sqlite.org/c3ref/wal_checkpoint_v2.html) and [source
code](2bd9f69d40
f447e7b5c098/src/wal.c#L2193).
It also does some small clean ups and fixes.
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Closes#1647
The salts values in the WAL header are (re)generated in every checkpoint (but in PASSIVE mode), so if we find a frame with mismatch it means it's a leftover from a previous checkpoint.
This is the first step towards rollback, since we still don't spill
pages with WAL, we can simply invalidate page cache in case of failure.
Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>
Closes#1599
- Instead of using a confusing CheckpointStatus for many different things,
introduce the following statuses:
* PagerCacheflushStatus - cacheflush can result in either:
- the WAL being written to disk and fsynced
- but also a checkpoint to the main BD file, and fsyncing the main DB file
Reflect this in the type.
* WalFsyncStatus - previously CheckpointStatus was also used for this, even
though fsyncing the WAL doesn't checkpoint.
* CheckpointStatus/CheckpointResult is now used only for actual checkpointing.
- Rename HaltState to CommitState (program.halt_state -> program.commit_state)
- Make WAL a non-optional property in Pager
* This gets rid of a lot of if let Some(...) boilerplate
* For ephemeral indexes, provide a DummyWAL implementation that does nothing.
- Rename program.halt() to program.commit_txn()
- Add some documentation comments to structs and functions
