Related to #144
- Separates `glob` and `like` regex caches, since the same pattern would
result in a different regex depending on which rules you apply
- Also fixes the value of `constant_mask` when translating LIKE
expressions now that non-constant pattern values are supported.
Note that LIKE and GLOB are almost entirely the same, the only
difference being the matching rules (so in our case, the regex
construction).
Closes#334
This reverts commit e365c12ce0, reversing
changes made to 21bd1a961e. The pull request broke some tests:
```
thread 'main' panicked at core/vdbe/mod.rs:1713:72:
index out of bounds: the len is 3 but the index is 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
while executing
"exec {*}$command"
(procedure "evaluate_sql" line 3)
invoked from within
"evaluate_sql $sqlite_exec $sql"
(procedure "run_test" line 2)
invoked from within
"run_test $::sqlite_exec $combined_sql $combined_expected_output"
(procedure "do_execsql_test" line 5)
invoked from within
"do_execsql_test sqlite_version {
SELECT sqlite_version();
} {3.46.1}"
(file "./testing/scalar-functions.test" line 434)
invoked from within
"source $testdir/scalar-functions.test"
(file "./testing/all.test" line 16)
make: *** [Makefile:59: test-compat] Error 1
```
### sqlite
<img width="792" alt="image" src="https://github.com/user-
attachments/assets/1a9238db-d948-4583-a808-f9adfec7c534">
### limbo
<img width="809" alt="image" src="https://github.com/user-
attachments/assets/ea3e5f7e-bb3e-450d-be34-59ca00128beb">
### Changes
- Add support for `sqlite_version()` function
- Update function's explain message depending on the number of arguments
Closes#331
Closes#319
1. Allow using a column as the pattern
2. Construct LIKE regexes with `^` and `$` so that eg the string
`'foobar'` does not match the pattern `'fooba'` unless the pattern
specifically has a wildcard
3. Support function expressions as the LIKE pattern
Closes#327
Reader's guide to this PR:
The aim is to have a more structured and maintainable approach to generating bytecode from the query AST so that different parts of the query processing pipeline have clearer responsibilities, so that developing new functionality is easier. E.g.:
- If you want to implement join reordering -> you do it in `Optimizer`
- If you want to implement `GROUP BY` -> you change `QueryPlanNode::Aggregate` to include it, parse it in `Planner` and handle the code generation for it in `Emitter`
The pipeline is:
`SQL text -> Parser -> Planner -> Optimizer -> Emitter`
and this pipeline generates:
`SQL text -> AST -> Logical Plan -> Optimized Logical Plan -> SQLite Bytecode`
---
Module structure:
`plan.rs`: defines the `Operator` enum. An `Operator` is a tree of other `Operators`, e.g. an `Operator::Join` has `left` and `right` children, etc.
`planner.rs`: Parses an `ast::Select` into a `Plan` which is mainly a wrapper for a root `Operator`
`optimizer.rs`: Makes a new `Plan` from an input `Plan` - does predicate pushdown, constant elimination and turns `Scan` nodes into `SeekRowId` nodes where applicable
`emitter.rs`: Generates bytecode instructions from an input `Plan`.
---
Adds feature `EXPLAIN QUERY PLAN <stmt>` which shows the logical query plan instead of the bytecode plan
---
Other changes:
- Almost everything from `select.rs` removed; things like `translate_aggregation()` moved to `expr.rs`
- `where_clause.rs` removed, some things from it like `translate_condition_expr()` moved to `expr.rs`
- i.e.: there is nothing _new_ in `expr.rs`, stuff just moved there
---
Concerns:
- Perf impact: there's a lot more indirection than before (`Operator`s are very "traditional" trees where they refer to other operators via Boxes etc)
Closes#281
