[arrow] branch master updated: ARROW-8862: [C++] NumericBuilder should use MemoryPool passed to CTOR

[ko...@apache.org]

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The following commit(s) were added to refs/heads/master by this push:
     new 741a95c  ARROW-8862: [C++] NumericBuilder should use MemoryPool passed to CTOR
741a95c is described below

commit 741a95cb9a9fff86e2b0c8e53a7e06d6b5c171bc
Author: Simon Watts <sa...@users.noreply.github.com>
AuthorDate: Wed May 20 06:58:53 2020 +0900

    ARROW-8862: [C++] NumericBuilder should use MemoryPool passed to CTOR
    
    `NumericBuilder` uses the `pool` (`MemoryPool*`) parameter to initialise the `ArrayBuilder` base class, but does not use it to initialise its own internal builder, `data_builder_` (`TypedBufferBuilder`).  For comparison `ArrayBuilder` uses the `pool` to initialise its own `null_bitmap_builder_` member (also a `TypedBufferBuilder`).
    
    This effect was observed when trying to switch to a custom `MemoryPool` for performance reasons.  A hook was used to detect any use of the `MemoryPool` proved by `default_memory_pool()`.
    
    Closes #7227 from sawatts/patch-1
    
    Authored-by: Simon Watts <sa...@users.noreply.github.com>
    Signed-off-by: Sutou Kouhei <ko...@clear-code.com>
---
 cpp/src/arrow/array/builder_primitive.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cpp/src/arrow/array/builder_primitive.h b/cpp/src/arrow/array/builder_primitive.h
index ae38c3b..d057f27 100644
--- a/cpp/src/arrow/array/builder_primitive.h
+++ b/cpp/src/arrow/array/builder_primitive.h
@@ -66,10 +66,10 @@ class NumericBuilder : public ArrayBuilder {
   template <typename T1 = T>
   explicit NumericBuilder(
       enable_if_parameter_free<T1, MemoryPool*> pool = default_memory_pool())
-      : ArrayBuilder(pool), type_(TypeTraits<T>::type_singleton()) {}
+      : ArrayBuilder(pool), type_(TypeTraits<T>::type_singleton()), data_builder_(pool) {}
 
   NumericBuilder(const std::shared_ptr<DataType>& type, MemoryPool* pool)
-      : ArrayBuilder(pool), type_(type) {}
+      : ArrayBuilder(pool), type_(type), data_builder_(pool) {}
 
   /// Append a single scalar and increase the size if necessary.
   Status Append(const value_type val) {