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Merged
alamb merged 2 commits into from
Nov 12, 2023
+99 −1
Merged

Add subtrait support for IS NULL and IS NOT NULL #8093

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d823c0d
added match arms and tests for is null
tgujar Nov 8, 2023
53a37dd
fixed formatting
tgujar Nov 9, 2023
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42 changes: 42 additions & 0 deletions datafusion/substrait/src/logical_plan/consumer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,10 @@ enum ScalarFunctionType {
Like,
/// [Expr::Like] Case insensitive operator counterpart of `Like`
ILike,
/// [Expr::IsNull]
IsNull,
/// [Expr::IsNotNull]
IsNotNull,
}

pub fn name_to_op(name: &str) -> Result<Operator> {
Expand Down Expand Up @@ -126,6 +130,8 @@ fn scalar_function_type_from_str(name: &str) -> Result<ScalarFunctionType> {
"not" => Ok(ScalarFunctionType::Not),
"like" => Ok(ScalarFunctionType::Like),
"ilike" => Ok(ScalarFunctionType::ILike),
"is_null" => Ok(ScalarFunctionType::IsNull),
"is_not_null" => Ok(ScalarFunctionType::IsNotNull),
others => not_impl_err!("Unsupported function name: {others:?}"),
}
}
Expand Down Expand Up @@ -880,6 +886,42 @@ pub async fn from_substrait_rex(
ScalarFunctionType::ILike => {
make_datafusion_like(true, f, input_schema, extensions).await
}
ScalarFunctionType::IsNull => {
let arg = f.arguments.first().ok_or_else(|| {
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@alamb alamb Nov 10, 2023

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I don't know if it matters, but this code doesn't check for f.arguments.len() > 1 so I think it will silently ignore any arguments after the first.

The same comment applies to IsNotNull

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@alamb alamb Nov 12, 2023

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On review, this is the same pattern used elsewhere in this PR

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@tgujar tgujar Nov 12, 2023

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Thanks for merging my PR! I think I could add checks for arg length here and also in other places where they are required in another PR

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@alamb alamb Nov 13, 2023

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Thank you @tgujar -- A follow on to make the argument checking handle too many arguments would be most appreciated. Thank you 🙏

DataFusionError::Substrait(
"expect one argument for `IS NULL` expr".to_string(),
)
})?;
match &arg.arg_type {
Some(ArgType::Value(e)) => {
let expr = from_substrait_rex(e, input_schema, extensions)
.await?
.as_ref()
.clone();
Ok(Arc::new(Expr::IsNull(Box::new(expr))))
}
_ => not_impl_err!("Invalid arguments for IS NULL expression"),
}
}
ScalarFunctionType::IsNotNull => {
let arg = f.arguments.first().ok_or_else(|| {
DataFusionError::Substrait(
"expect one argument for `IS NOT NULL` expr".to_string(),
)
})?;
match &arg.arg_type {
Some(ArgType::Value(e)) => {
let expr = from_substrait_rex(e, input_schema, extensions)
.await?
.as_ref()
.clone();
Ok(Arc::new(Expr::IsNotNull(Box::new(expr))))
}
_ => {
not_impl_err!("Invalid arguments for IS NOT NULL expression")
}
}
}
}
}
Some(RexType::Literal(lit)) => {
Expand Down
48 changes: 47 additions & 1 deletion datafusion/substrait/src/logical_plan/producer.rs
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Expand Up @@ -1025,7 +1025,53 @@ pub fn to_substrait_rex(
col_ref_offset,
extension_info,
),
_ => not_impl_err!("Unsupported expression: {expr:?}"),
Expr::IsNull(arg) => {
let arguments: Vec<FunctionArgument> = vec![FunctionArgument {
arg_type: Some(ArgType::Value(to_substrait_rex(
arg,
schema,
col_ref_offset,
extension_info,
)?)),
}];

let function_name = "is_null".to_string();
let function_anchor = _register_function(function_name, extension_info);
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@alamb alamb Nov 10, 2023

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Very minor, but why not call this function_reference to match the field name used below?

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@alamb alamb Nov 12, 2023

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While reviewing the code again, I found this simply follows the same pattern as the existing substrait code, so looks good to me

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@alamb alamb Nov 13, 2023 •
edited
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@tgujar if you have time, it would also be awesome if you could make a PR that renames this variable (and other uses of _register_function to function_reference which I think would make the code cleaner

Ok(Expression {
rex_type: Some(RexType::ScalarFunction(ScalarFunction {
function_reference: function_anchor,
arguments,
output_type: None,
args: vec![],
options: vec![],
})),
})
}
Expr::IsNotNull(arg) => {
let arguments: Vec<FunctionArgument> = vec![FunctionArgument {
arg_type: Some(ArgType::Value(to_substrait_rex(
arg,
schema,
col_ref_offset,
extension_info,
)?)),
}];

let function_name = "is_not_null".to_string();
let function_anchor = _register_function(function_name, extension_info);
Ok(Expression {
rex_type: Some(RexType::ScalarFunction(ScalarFunction {
function_reference: function_anchor,
arguments,
output_type: None,
args: vec![],
options: vec![],
})),
})
}
_ => {
not_impl_err!("Unsupported expression: {expr:?}")
}
}
}

Expand Down
10 changes: 10 additions & 0 deletions datafusion/substrait/tests/cases/roundtrip_logical_plan.rs
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Expand Up @@ -314,6 +314,16 @@ async fn simple_scalar_function_substr() -> Result<()> {
roundtrip("SELECT * FROM data WHERE a = SUBSTR('datafusion', 0, 3)").await
}

#[tokio::test]
async fn simple_scalar_function_is_null() -> Result<()> {
roundtrip("SELECT * FROM data WHERE a IS NULL").await
}

#[tokio::test]
async fn simple_scalar_function_is_not_null() -> Result<()> {
roundtrip("SELECT * FROM data WHERE a IS NOT NULL").await
}

#[tokio::test]
async fn case_without_base_expression() -> Result<()> {
roundtrip("SELECT (CASE WHEN a >= 0 THEN 'positive' ELSE 'negative' END) FROM data")
Expand Down