We have so many cursor types that it will be unbearable to properly make
all of them work. Let's simplify this and only focus on lazy cursor
which in the future will load from database in case we need it.
Closes#2333
We have so many cursor types that it will be unbearable to properly make
all of them work. Let's simplify this and only focus on lazy cursor
which in the future will load from database in case we need it.
Changes a couple of function signatures to return `Completion`. Also, I
changed `Completion` to be internally `Arc` to abstract the `Arc`
implementation detail, and to be able to attach a `#[must_use]` to the
`Completion` struct, so that cargo check can show us where we are not
tracking completions in the code. I also attached a `#[must_use]` to
`IOResult` so that we can see the places that we are not propagating or
waiting for I/O, demonstrating locations where functions should be
reentrant and are not.
Also, while we are with this refactor in progress I want to relax the
Clippy CI lint on unused_variables.
Closes#2309
We need to ensures that there is a single, shared `Database` object per
a database file. We need because it is not safe to have multiple
independent WAL files open because coordination happens at process-level
POSIX file advisory locks.
Fixes#2267
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Closes#2299
We need to ensures that there is a single, shared `Database` object per
a database file. We need because it is not safe to have multiple
independent WAL files open because coordination happens at process-level
POSIX file advisory locks.
Fixes#2267
Co-authored-by: ultraman <sunhuayangak47@gmail.com>
Closes#2225.
## What
We currently do not use pages in the
[freelist](https://www.sqlite.org/fileformat.html#the_freelist) at all
when allocating new pages.
## Why is this bad
The effect of this is that 1. UPDATEs with overflow pages become really
slow and 2. the database size grows really quickly. See #2225 for an
extreme example comparison with SQLite.
## The fix
Whenever `allocate_page()` is called, we first check if we have pages in
the freelist, and if we do, we recycle one of those pages instead of
creating a new one. If there are no freelist pages, we allocate a new
page as normal.
## Implementation notes
- `allocate_page()` now needs to return an `IOResult`, which means all
of its callers also need to return an `IOResult`, necessitating quite a
bit of new state machine logic to ensure re-entrancy.
- I left a few "synchronous IO hacks" in the `balance()` routine because
the size of this PR would balloon even more than it already has if I
were to fix those immediately in this PR.
- `fill_cell_payload()` uses some `unsafe` code to avoid lifetime
issues, and adds an unfortunate double-indirection via
`Arc<Mutex<Vec<T>>>` because the existing btree code constantly clones
`WriteState`, and we must ensure the underlying buffers referenced by
raw pointers in `fill_cell_payload` remain valid.
**Follow-up cleanups:**
1. remove synchronous IO hacks that would require even more state
machines and are best left for another PR
2. remove `Clone` from `WriteState` and implement it better
## Perf comparison
`main`: 33 seconds
```
jussi@Jussis-MacBook-Pro limbo % time target/release/tursodb --experimental-indexes apinatest_main.db <<'EOF'
create table t(x, y, z unique);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
EOF
Turso v0.1.3-pre.3
Enter ".help" for usage hints.
This software is ALPHA, only use for development, testing, and experimentation.
target/release/tursodb --experimental-indexes apinatest_main.db <<<'' 6.81s user 21.18s system 83% cpu 33.643 total
```
PR: 13 seconds
```
jussi@Jussis-MacBook-Pro limbo % time target/release/tursodb --experimental-indexes apinatest_PR.db <<'EOF'
create table t(x, y, z unique);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
insert into t select randomblob(1024*128),randomblob(1024*128),randomblob(1024*128) from generate_series(1, 100);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
update t set x = x + 1 WHERE z > randomblob(1024*128);
EOF
Turso v0.1.3-pre.3
Enter ".help" for usage hints.
This software is ALPHA, only use for development, testing, and experimentation.
target/release/tursodb --experimental-indexes apinatest_PR.db <<<'' 3.89s user 7.83s system 89% cpu 13.162 total
```
(sqlite: 2 seconds 🤡 )
---
TODO:
- [x] Fix whatever issue the simulator caught in CI (#2238 )
- [x] Post a performance comparison
- [x] Fix autovacuum test failure
- [x] Improve docs
- [x] Fix `fill_cell_payload` re-entrancy issue when allocating overflow
pages
- [x] Add proper PR description
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Closes#2233
