Paquet and JSON readers use Arc<Expression> to avoid deep copies #364
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| @@ -79,7 +80,7 @@ fn as_inverted_data_skipping_predicate(expr: &Expr) -> Option<Expr> { | |||
| as_data_skipping_predicate(&expr) | |||
| } | |||
| VariadicOperation { op, exprs } => { | |||
| let expr = Expr::variadic(op.invert(), exprs.iter().cloned().map(Expr::not)); | |||
| let expr = Expr::variadic(op.invert(), exprs.iter().cloned().map(|e| !e)); | |||
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Given that we actually bothered to impl std::ops::Not for Expression, we may as well use it!
(Expr::not is really just shorthand for std::ops::Not::not, and requires the appropriate import. By contrast,! is compiler magic and does not require any import)
| None => return None, | ||
| }; | ||
|
|
||
| let predicate = predicate.as_deref()?; |
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Deref is black magic, but it's sure nice when it works!
(trying just predicate? gives a compilation error)
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Because Try isn't implemented on &Option as_deref converts &Option<T> to Option<&T> https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref
| @@ -467,7 +464,7 @@ fn transform_to_logical_internal( | |||
| .get_expression_handler() | |||
| .get_evaluator( | |||
| read_schema, | |||
| read_expression.clone(), | |||
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #364 +/- ##
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- Coverage 78.25% 78.22% -0.04%
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Files 49 49
Lines 10256 10253 -3
Branches 10256 10253 -3
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- Hits 8026 8020 -6
- Misses 1780 1783 +3
Partials 450 450 ☔ View full report in Codecov by Sentry. |
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| @@ -467,7 +464,7 @@ fn transform_to_logical_internal( | |||
| .get_expression_handler() | |||
| .get_evaluator( | |||
| read_schema, | |||
| read_expression.clone(), | |||
Today, the engine parquet/json file handler APIs take an
Expressionarg for predicate pushdown. They cannot take a reference, because the iterator they return will likely depend on (but outlive) that reference. Worse, they need to do it for every file the query reads. Unfortunately, data skipping predicates can be arbitrarily large, and thus annoying/expensive to copy so much. We already use Arc to protect schemas (some of the time, at least), and we can start using Arc to protect expressions as well.