This makes it work like in SQLite where only one schema writer is permitted and readers will return error while preparing statement if the schema is changing.
This PR cleans up some comments in the extension API and prevents
extensions themselves from calling 'free' on Value types that are
exposed to the user facing traits, as well as changes the `from_ffi`
method for OwnedValues to take ownership and automatically free the
values to prevent memory leaks.
This PR also finds the name of the `args: &[Value]` argument for scalar
functions in extensions, and uses that in the proc macro, instead of
relying on documentation to communicate that the parameter must be named
`args`.
Closes#1054
Beep boop.
What happened you ask? I removed the dumb balancing algorithm I
implemented in favor of SQLite's implementation based on B*Tree[1] where
a page is 2/3 full instead of 1/2. It also tries to balance a page by
taking a maximum 3 pages and distributing cells evenly between them.
I've made some changes that are somewhat related:
* Moved most operations on pages out of BTreeCursor because those
operations are based on a page, not on a cursor, and it makes it easier
to test.
* Fixed `write_u16` and `read_u16` cases that didn't need a implicit
offset calculation. Added: `write_u16_no_offset` and
`read_u16_no_offset` to counter this.
* Added some tests with fuzz testing too.
* Fixed some important actions like: `compute_free_space`,
`defragment_page` and `drop_cell`.
[1] https://dl.acm.org/doi/10.1145/356770.356776Closes#968
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.
```console
thread 'fuzz::tests::logical_expression_fuzz_run' panicked at tests\integration\fuzz\mod.rs:818:13:
assertion `left == right` failed: query: SELECT ( ( 3622873 || -8851250 ) * ( ( ( -124 ) + ( -5792536 ) ) ) ) = ( 179434259456392 < 65481085924370 ), limbo: [[Integer(1)]], sqlite: [[Integer(0)]]
left: [[Integer(1)]]
right: [[Integer(0)]]
```
This and a few other failing fuzzing tests were due to incorrectly
parsing numerics from strings. Some of our casting was done properly,
but it wasn't being applied to all cases where the behavior was needed.
It was also attempting to parse a string[0..N] N times until
`string[0..N].parse()` would no longer succeed. This searches for the
index of the first illegal character and parses the resulting slice
once.
Tests were added for some of the edgecases that were previously failing.
This PR also adds a macro in vdbe/insn.rs that allows for a bit of
cleanup and reduces some matching.
Closes#1053
This PR started out as one to improve the API of extensions but I ended
up building on top of this quite a bit and it just kept going. Sorry
this one is so large but there wasn't really a good stopping point, as
it kept leaving stuff in broken states.
**VCreate**: Support for `CREATE VIRTUAL TABLE t USING vtab_module`
**VUpdate**: Support for `INSERT` and `DELETE` methods on virtual
tables.
Sqlite uses `xUpdate` function with the `VUpdate` opcode to handle all
insert/update/delete functionality in virtual tables..
have to just document that:
```
if args[0] == NULL: INSERT args[1] the values in args[2..]
if args[1] == NULL: DELETE args[0]
if args[0] != NULL && len(args) > 2: Update values=args[2..] rowid=args[0]
```
I know I asked @jussisaurio on discord about this already, but it just
sucked so bad that I added some internal translation so we could expose
a [nice API](https://github.com/tursodatabase/limbo/pull/996/files#diff-
3e8f8a660b11786745b48b528222d11671e9f19fa00a032a4eefb5412e8200d1R54) and
handle the logic ourselves while keeping with sqlite's opcodes.
I'll change it back if I have to, I just thought it was genuinely awful
to have to rely on comments to explain all that to extension authors.
The included extension is not meant to be a legitimately useful one, it
is there for testing purposes. I did something similar in #960 using a
test extension, so I figure when they are both merged, I will go back
and combine them into one since you can do many kinds at once, and that
way it will reduce the amount of crates and therefore compile time.
1. Remaining opcodes.
2. `UPDATE` (when we support the syntax)
3. `xConnect` - expose API for a DB connection to a vtab so it can
perform arbitrary queries.
Closes#996
This PR fixes
[#1040](https://github.com/tursodatabase/limbo/issues/1040) and modifies
the `LIKE` function in the VDBE to work on expressions of all types like
SQLite.
Looking at how SQLite handles this, it gets the text value of the
expression regardless of its affinity. I used `exec_cast(exp, "TEXT")`
to achieve the same effect. Since most `LIKE` queries will probably be
done on `TEXT` expressions, I avoid casting the expression if it's
already `TEXT`. If either of the expressions was `NULL`, SQLite returns
nothing i.e. `NULL`. I also changed the unreachable arm message from
`Like on non-text registers` to `Like failed`.
The following queries produced the same results in Limbo:
```
SQLite version 3.46.1 2024-08-13 09:16:08 (UTF-16 console I/O)
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
sqlite> CREATE TABLE tbl (n NULL, i INTEGER, r REAL, t TEXT, b BLOB);
sqlite> INSERT INTO tbl VALUES(NULL,1,2.0,'a',X'0500');
sqlite> SELECT * FROM tbl;
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE n LIKE NULL;
sqlite> SELECT * FROM tbl WHERE n LIKE 'NULL';
sqlite> SELECT * FROM tbl WHERE n LIKE 1;
sqlite> SELECT * FROM tbl WHERE n LIKE 2.0;
sqlite> SELECT * FROM tbl WHERE n LIKE x'0500';
sqlite>
sqlite> SELECT * FROM tbl WHERE i LIKE NULL;
sqlite> SELECT * FROM tbl WHERE i LIKE 1;
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE i LIKE '1';
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE i LIKE 2.0;
sqlite> SELECT * FROM tbl WHERE i LIKE 1.0;
sqlite> SELECT * FROM tbl WHERE i LIKE x'0500';
sqlite>
sqlite> SELECT * FROM tbl WHERE r LIKE NULL;
sqlite> SELECT * FROM tbl WHERE r LIKE 2;
sqlite> SELECT * FROM tbl WHERE r LIKE 2.0;
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE r LIKE '2.0';
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE r LIKE 'a';
sqlite> SELECT * FROM tbl WHERE r LIKE x'0500';
sqlite>
sqlite> SELECT * FROM tbl WHERE t LIKE NULL;
sqlite> SELECT * FROM tbl WHERE t LIKE 1;
sqlite> SELECT * FROM tbl WHERE t LIKE 2.0;
sqlite> SELECT * FROM tbl WHERE t LIKE 'a';
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE t LIKE x'0500';
sqlite>
sqlite> SELECT * FROM tbl WHERE b LIKE NULL;
sqlite> SELECT * FROM tbl WHERE b LIKE 1;
sqlite> SELECT * FROM tbl WHERE b LIKE 2.0;
sqlite> SELECT * FROM tbl WHERE b LIKE 'a';
sqlite> SELECT * FROM tbl WHERE b LIKE x'0500';
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE b LIKE 'x''0500''';
sqlite> SELECT * FROM tbl WHERE b LIKE '♣';
sqlite>
sqlite> SELECT * FROM tbl WHERE 1 LIKE 1;
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE 2.0 LIKE 2.0;
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE 2.0 LIKE '2.0';
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE '2.0' LIKE 2.0;
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE '123.45' LIKE 123.45;
|1|2.0|a|♣
sqlite> SELECT * FROM tbl WHERE NULL LIKE NULL;
sqlite> SELECT * FROM tbl WHERE x'0500' LIKE x'0500';
|1|2.0|a|♣
sqlite> SELECT typeof(n), typeof(i), typeof(r), typeof(t), typeof(b) FROM tbl;
null|integer|real|text|blob
```
Though, these queries are very basic, and more testing could be done.
Closes#1044
the command for drop table translation has been updated so that it more closely matches the semantics of SQLite's drop table command.
there are a few more things missing like ephemeral tables, destroy etc.
this is the initial commit is for the implementation of DROP TABLE. It adds support for the DROP TABLE instruction and adds a DropBTree instruction. It also implements the btree_drop method in btree.rs which makes use of free_page method which will be implemented via PR https://github.com/tursodatabase/limbo/pull/785
