The original `rowid_seek_fuzz` test had a design flaw: it inserted contiguous
integers, which prevented issues such as the one fixed in #2065 from being
discovered.
Further, the test has at some point also been neutered a bit by only inserting
100 values which makes the btree very small, hiding interactions between interior
pages and neighboring leaf pages.
This should not be merged until #2065 is merged.
We store `last_checksum` to do cumulative checksumming. After reading
wal for recovery, we didn't set last checksum properly in case there
were no frames so this cause us to not initialize last_checksum
properly.
Was running the sim with I/O faults enabled and fixed some nasty bugs.
Now, there are some more nasty bugs to fix as well. This is the command
that I use to run the simulator `cargo run -p limbo_sim -- --minimum-
tests 10 --maximum-tests 1000`
This PR mainly fixes the following bugs:
- Not decrementing in flight write counter when `pwrite` fails
- not rolling back the transaction on `step` error
- not rolling back the transaction on `run_once` error
- some functions were just being unwrapped when they could suffer io
errors
- Only change max_frame after wal sync's
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Closes#1946
`db_size` is `>0` in case of last frame written of a transaction. This
is necessary as we need to know -- while recovering wal contents -- that
we have read a transaction fully instead of treating every frame as its
own transaction.
Closes#1866
Makes it easier to test the feature:
```
$ cargo run -- --experimental-indexes
Limbo v0.0.22
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database
limbo> CREATE TABLE t(x);
limbo> CREATE INDEX t_idx ON t(x);
limbo> DROP INDEX t_idx;
```
Previously we implemented update as a simple `Delete` + `Insert`
procedure which seemed okay for the moment but it wasn't. `Delete` can
trigger balance and a post balance `seek` which will leave cursor
pointing to an invalid page which `Insert` will try to insert to.
We solve this by removing `Delete` from the execution plan and rely on
`Insert` to properly overwrite the cell where the rowid is the same as
the one we are inserting.
It is easy to chalk this fuzzer issue to erratic floating point
behaviour, but this is not the case here.
Currently, `exec_math_log` calculates log with arbitrary bases by using
the following formula: `log_a(b) ~= ln(b) / ln(a)`. This calculation is
an approximation with lots of its floating point precision lost to
dividing the results of natural logarithms.
By using the specialized versions of the log functions (`log2` &
`log10`), we can avoid this loss of precision.
SQLite also uses these specialized log functions when possible, so it
doesn't hurt to do the same thing when aiming for parity.
We were incorrectly setting `moved_before` as `false` after checking
for unique constraint violation, but the reality is that after the
uniqueness check, we are already correctly positioned -- if no match
was found, the cursor is positioned at either:
a) no row, or
b) at the first entry that is greater than the key we are inserting.
This means we don't have to move anymore and can just insert.
This PR implements SQLite-compatible affinity-based type coercion for
seek operations and comparison operators, bringing Limbo's behavior
closer to SQLite's type conversion rules.
### Key Changes
- Added affinity handling to all comparison operators (`Eq`, `Ne`, `Lt`,
`Le`, `Gt`, `Ge`).
- Added `get_expr_affinity()` to determine expression affinity based on
column types and casts.
- Added affinity functionality `CmpInsFlags` which carries the affinity
information from translation layer to execution layer.
- Added comprehensive `apply_numeric_affinity()` function that handles
many edge cases when converting to numerical quantities.
- Implemented `comparison_affinity()` that follows SQLite's affinity
precedence rules.
- Added fuzz tests for partial numeric strings, hex literals, and
various numeric formats.
### SQLite Compatibility Improvements
This implementation now correctly handles cases like:
- `SELECT * FROM t WHERE x < X'41'` (blob comparisons)
- `SELECT * FROM t WHERE x < '123abc'` (partial numeric strings)
- `SELECT * FROM t WHERE x < 4.9 ` (float precision in seeks)
- Mixed-type comparisons with proper affinity conversion
Thanks 🤝@PThorpe92 and @pedrocarlo for helping improve my planner
understanding.
Closes: https://github.com/tursodatabase/limbo/issues/1607Closes#1680
Closes#1528 .
- Modified `translate_select` so that the caller can define if the
statement is top-level statement or a subquery.
- Refactored `translate_insert` to offload the translation of multi-row
VALUES and SELECT statements to `translate_select`
- I did not try to change much of `populate_column_registers` as I did
not want to break `translate_virtual_table_insert`. Ideally, I would
want to unite this remaining logic folding `populate_column_registers`
into `populate_columns_multiple_rows` and the
`translate_virtual_table_insert` into `translate_insert`. But, I think
this may be best suited for a separate PR.
## TODO
- ~Tests~ - *Done*
- ~Need to emit a temp table when we are selecting and inserting into
the Same Table -
https://github.com/sqlite/sqlite/blob/master/src/insert.c#L1369~ -
*Done*
- Optimization when table have the exact same schema - open an Issue
about it
- Virtual Tables do not benefit yet from this feature - open an Issue
about it
Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>
Closes#1566
