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Better join order resolution logic #797

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Merged
merged 3 commits into from
Aug 5, 2021
Merged

Better join order resolution logic #797

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d75f432
better join order resolution logic
seddonm1 Jul 31, 2021
8fa689c
simplify by using existing methods
seddonm1 Aug 3, 2021
f6ae147
remove unneeded clone and minor formatting
seddonm1 Aug 4, 2021
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65 changes: 56 additions & 9 deletions datafusion/src/logical_plan/builder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -287,16 +287,63 @@ impl LogicalPlanBuilder {
.into_iter()
.zip(join_keys.1.into_iter())
.map(|(l, r)| {
let mut swap = false;
let l = l.into();
let left_key = l.clone().normalize(&self.plan).or_else(|_| {
swap = true;
l.normalize(right)
});
if swap {
(r.into().normalize(&self.plan), left_key)
} else {
(left_key, r.into().normalize(right))
let r = r.into();

match (&l.relation, &r.relation) {
(Some(lr), Some(rr)) => {
let l_is_left =
self.plan.schema().field_with_qualified_name(lr, &l.name);
let l_is_right =
right.schema().field_with_qualified_name(lr, &l.name);
let r_is_left =
self.plan.schema().field_with_qualified_name(rr, &r.name);
let r_is_right =
right.schema().field_with_qualified_name(rr, &r.name);

match (l_is_left, l_is_right, r_is_left, r_is_right) {
(_, Ok(_), Ok(_), _) => (Ok(r), Ok(l)),
(Ok(_), _, _, Ok(_)) => (Ok(l), Ok(r)),
_ => (l.normalize(&self.plan), r.normalize(right)),
}
}
(Some(lr), None) => {
let l_is_left =
self.plan.schema().field_with_qualified_name(lr, &l.name);
let l_is_right =
right.schema().field_with_qualified_name(lr, &l.name);

match (l_is_left, l_is_right) {
(Ok(_), _) => (Ok(l), r.normalize(right)),
(_, Ok(_)) => (r.normalize(&self.plan), Ok(l)),
_ => (l.normalize(&self.plan), r.normalize(right)),
}
}
(None, Some(rr)) => {
let r_is_left =
self.plan.schema().field_with_qualified_name(rr, &r.name);
let r_is_right =
right.schema().field_with_qualified_name(rr, &r.name);

match (r_is_left, r_is_right) {
(Ok(_), _) => (Ok(r), l.normalize(right)),
(_, Ok(_)) => (l.normalize(&self.plan), Ok(r)),
_ => (l.normalize(&self.plan), r.normalize(right)),
}
}
(None, None) => {
let mut swap = false;
let left_key =
l.clone().normalize(&self.plan).or_else(|_| {
swap = true;
l.normalize(right)
});
if swap {
(r.normalize(&self.plan), left_key)
} else {
(left_key, r.normalize(right))
}
}
}
})
.unzip();
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11 changes: 11 additions & 0 deletions datafusion/tests/sql.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1730,6 +1730,17 @@ async fn equijoin() -> Result<()> {
let actual = execute(&mut ctx, sql).await;
assert_eq!(expected, actual);
}

let mut ctx = create_join_context_qualified()?;
let equivalent_sql = [
"SELECT t1.a, t2.b FROM t1 INNER JOIN t2 ON t1.a = t2.a ORDER BY t1.a",
"SELECT t1.a, t2.b FROM t1 INNER JOIN t2 ON t2.a = t1.a ORDER BY t1.a",
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@alamb alamb Aug 3, 2021

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What about something like

        "SELECT t1.a, t2.b FROM t1 INNER JOIN t2 ON a = t1.a ORDER BY t1.a",

? I would expect it to given an error about ambiguous relation name

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@seddonm1 seddonm1 Aug 3, 2021

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Thanks I will add more tests.

];
let expected = vec![vec!["1", "100"], vec!["2", "200"], vec!["4", "400"]];
for sql in equivalent_sql.iter() {
let actual = execute(&mut ctx, sql).await;
assert_eq!(expected, actual);
}
Ok(())
}

Expand Down