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Minor: Cleanup BuiltinScalarFunction's phys-expr creation #8114

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merged 1 commit into from
Nov 10, 2023

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2010YOUY01
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Which issue does this PR close?

Cleanup for #8045

Rationale for this change

In current implementation, some function tries to generate input type specific physical expressions in
https://github.com/apache/arrow-datafusion/blob/308c35404939ed39e4e398054d6fc78c89817109/datafusion/physical-expr/src/functions.rs#L75-L204
However, this can be done inside function implementation like most other functions did, this PR would like to unify the implementation approach

What changes are included in this PR?

Move input-type-specific BuiltinScalarFunction physical expression creation to inside function implementation

Are these changes tested?

Covered by existing tests

Are there any user-facing changes?

No

@github-actions github-actions bot added the physical-expr Physical Expressions label Nov 10, 2023
@jonahgao
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I wonder if this modification will lead to performance degradation.

Each time we evaluate the function expression, we have to pick an implementation based on the input type.
Previously, the picking was executed only once during compilation/planning.

@2010YOUY01
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I wonder if this modification will lead to performance degradation.

Each time we evaluate the function expression, we have to pick an implementation based on the input type. Previously, the picking was executed only once during compilation/planning.

That's a good point, but I think for this case, the extra overhead is one or two function calls per batch(typically 8k rows)
I tried those functions on TPCH data, and there is no noticeable difference

select to_timestamp(l_shipdate), to_timestamp_seconds(l_commitdate), to_timestamp_millis(l_receiptdate), to_timestamp_micros(l_shipdate), to_timestamp_nanos(l_shipdate), from_unixtime(l_orderkey), abs(l_orderkey) from lineitem;

@@ -17,6 +17,8 @@

//! DateTime expressions

use crate::datetime_expressions;
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Suggested change
use crate::datetime_expressions;

It seems that this use may not be required 🤔.

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🤔 but clippy did not flag it

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@jonahgao jonahgao left a comment

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Looks good to me 👍

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@alamb alamb left a comment

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Thank you @2010YOUY01 -- looks really good

Also thank you @jonahgao for your guidance and review

@@ -17,6 +17,8 @@

//! DateTime expressions

use crate::datetime_expressions;
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🤔 but clippy did not flag it

@@ -927,11 +811,19 @@ pub fn create_physical_fun(
}),
BuiltinScalarFunction::Upper => Arc::new(string_expressions::upper),
BuiltinScalarFunction::Uuid => Arc::new(string_expressions::uuid),
_ => {
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👍 for removing the catchall

@alamb alamb merged commit e727bbf into apache:main Nov 10, 2023
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3 participants