From fb8b6f3aad8d339a51730e15c97286d6a5aaf0f9 Mon Sep 17 00:00:00 2001
From: Afrizal Fikri <laser.survivor@gmail.com>
Date: Fri, 15 Oct 2021 23:02:46 +0700
Subject: [PATCH] Improved performance of writing decimal to `parquet` (#528)

---
 src/io/parquet/write/mod.rs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/io/parquet/write/mod.rs b/src/io/parquet/write/mod.rs
index a9537592b11..b40fccac59e 100644
--- a/src/io/parquet/write/mod.rs
+++ b/src/io/parquet/write/mod.rs
@@ -298,9 +298,7 @@ pub fn array_to_page(
                 primitive::array_to_page::<i64, i64>(&array, options, descriptor)
             } else {
                 let size = decimal_length_from_precision(precision);
-
-                let mut values = MutableBuffer::<u8>::new(); // todo: this can be estimated
-
+                let mut values = MutableBuffer::<u8>::with_capacity(size * array.len());
                 array.values().iter().for_each(|x| {
                     let bytes = &x.to_be_bytes()[16 - size..];
                     values.extend_from_slice(bytes)