(arrow-go) branch main updated: optimization: comparison: when DataType is static, skip reflection (#542)

[zeroshade]

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zeroshade pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow-go.git


The following commit(s) were added to refs/heads/main by this push:
     new 99484e92 optimization: comparison: when DataType is static, skip 
reflection (#542)
99484e92 is described below

commit 99484e92e9248c6d92b8dbd466fb471ea0c23a2f
Author: pixelherodev <n...@pingthings.io>
AuthorDate: Thu Oct 23 16:00:39 2025 -0500

    optimization: comparison: when DataType is static, skip reflection (#542)
    
    ### Rationale for this change
    
    Reflection is slow. When working with primitive data types - e.g.
    PrimitiveType.Float64 - the DataType value is a constant consisting of
    the (constant) type indicator, and the constant pointer to the only
    instance of the Float64 type. For such cases, we can do a fast-path for
    TypeEqual and detect the interface equality without the current path of
    switching on the type of DataType, and using reflect.DeepEqual.
    
    reflect.DeepEqual makes several allocations and is not particularly
    fast. This patch cuts out 50-75% of the runtime of `schema.Equals` in
    our real-world scenario in my testing.
    
    ### What changes are included in this PR?
    
    A branch is added to the TypeEqual switch, which returns early when the
    two types compare equal through shallow comparison. In such a case,
    deeper comparison must necessarily show equality, as every property is
    definitionally identical. Detecting this early can make e.g. schema
    validations significantly faster.
    
    ### Are these changes tested?
    
    Yes, though only with our internal schemas. I noticed arrow showing up
    heavily in our profiles and started hacking on it to make it go away :)
    
    ### Are there any user-facing changes?
    
    It runs faster? That's technically user-facing ;)
    
    Co-authored-by: Noam Preil <n...@pixelhero.dev>
---
 arrow/compare.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arrow/compare.go b/arrow/compare.go
index 58569b33..8966f16c 100644
--- a/arrow/compare.go
+++ b/arrow/compare.go
@@ -45,8 +45,10 @@ func TypeEqual(left, right DataType, opts 
...TypeEqualOption) bool {
        }
 
        switch {
+       case left == right:
+               return true
        case left == nil || right == nil:
-               return left == nil && right == nil
+               return false
        case left.ID() != right.ID():
                return false
        }