liurenjie1024 opened a new issue, #2633:
URL: https://github.com/apache/arrow-datafusion/issues/2633
There are some discussions about datafusion's optimizer framework in #440
and #1972. And I tried to build a framework based datafusion's expression
system with the following features:
1. Includes a heuristic optimizer that applies rules to plan iteratively in
different ways: top-down or bottom-up. The optimizer stops applying rules to
the plan until reaching a fixpoint or max iteration times.
2. Includes a cascades style cost-based optimizer framework.
3. Pattern matching and binding for rules.
Following is an example of removing limit rule, including patten definition
and rule implementation:
```
pattern(|op| matches!(op, Logical(LogicalLimit(_))))
.leaf(|op| matches!(op, Logical(LogicalProjection(_))))
.finish()
```
```
if let (Logical(LogicalLimit(limit1)), Logical(LogicalLimit(limit2))) =
(input.get_operator(&_ctx)?, input[0].get_operator(&_ctx)?)
{
let new_limit = min(limit1.limit(), limit2.limit());
let ret =
input[0].clone_with_inputs(Logical(LogicalLimit(Limit::new(new_limit))));
result.add(ret);
Ok(())
} else {
bail!("Pattern miss matched")
}
```
And the source code can be found here:
https://github.com/liurenjie1024/rust-opt-framework
Welcome to discuss and share your thoughts.
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