From 23a5808833c757a2c824b1fdb5c10183d8a3d8e4 Mon Sep 17 00:00:00 2001
From: Ivan Tham <pickfire@riseup.net>
Date: Sun, 25 Jul 2021 20:46:20 +0800
Subject: [PATCH] Try reusing memory

Fix #10
---
 Cargo.lock               |  9 +++++++++
 Cargo.toml               |  3 ++-
 src/bin/basic_batched.rs | 38 ++++++++++++++++++++------------------
 3 files changed, 31 insertions(+), 19 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 13942ab..204402d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,5 +1,7 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+version = 3
+
 [[package]]
 name = "ahash"
 version = "0.4.7"
@@ -214,6 +216,7 @@ version = "0.1.0"
 dependencies = [
  "num_cpus",
  "rand",
+ "rsor",
  "rusqlite",
  "sqlx",
  "tokio",
@@ -822,6 +825,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "rsor"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7e89d08ecc43776a04f71ea96132897f591887209c0c0a6b266e6752b584159e"
+
 [[package]]
 name = "rusqlite"
 version = "0.25.3"
diff --git a/Cargo.toml b/Cargo.toml
index b1aa9a8..e6a63b5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,4 +10,5 @@ sqlx = { version = "0.5.2", features = ["runtime-tokio-native-tls", "sqlite"]}
 tokio = {version = "1.5.0", features = ["full"]}
 rand = "0.8.3"
 num_cpus = "1.0"
-rusqlite = "0.25.3"
\ No newline at end of file
+rusqlite = "0.25.3"
+rsor = "0.1"
diff --git a/src/bin/basic_batched.rs b/src/bin/basic_batched.rs
index 21700bc..e8cb294 100644
--- a/src/bin/basic_batched.rs
+++ b/src/bin/basic_batched.rs
@@ -8,6 +8,7 @@
 //! next: basic_batched_wp.rs
 
 use rusqlite::{Connection, ToSql, Transaction};
+use rsor::Slice;
 
 mod common;
 
@@ -46,34 +47,35 @@ fn faker(tx: &Transaction, count: i64) {
 
     let mut stmt_with_area = tx.prepare_cached(st1.as_str()).unwrap();
     let mut stmt = tx.prepare_cached(st2.as_str()).unwrap();
+    let mut params_with_area = Vec::with_capacity(min_batch_size as usize);
+    let mut param_values = Slice::with_capacity(min_batch_size as usize * 3);
     for _ in 0..(count / min_batch_size) {
         let with_area = common::get_random_bool();
         let age = common::get_random_age();
         let is_active = common::get_random_active();
-        let mut param_values: Vec<_> = Vec::new();
         if with_area {
-            // lets prepare the batch
-            let mut vector = Vec::<(String, i8, i8)>::new();
             for _ in 0..min_batch_size {
                 let area_code = common::get_random_area_code();
-                vector.push((area_code, age, is_active));
-            }
-            for batch in vector.iter() {
-                param_values.push(&batch.0 as &dyn ToSql);
-                param_values.push(&batch.1 as &dyn ToSql);
-                param_values.push(&batch.2 as &dyn ToSql);
+                params_with_area.push((area_code,));
             }
+            let param_values = param_values.fill(|mut v| {
+                for params in &params_with_area {
+                    v.push(&params.0 as &dyn ToSql);
+                    v.push(&age as &dyn ToSql);
+                    v.push(&is_active as &dyn ToSql);
+                }
+                v
+            });
             stmt_with_area.execute(&*param_values).unwrap();
+            params_with_area.clear();
         } else {
-            // lets prepare the batch
-            let mut vector = Vec::<(i8, i8)>::new();
-            for _ in 0..min_batch_size {
-                vector.push((age, is_active));
-            }
-            for batch in vector.iter() {
-                param_values.push(&batch.0 as &dyn ToSql);
-                param_values.push(&batch.1 as &dyn ToSql);
-            }
+            let param_values = param_values.fill(|mut v| {
+                for _ in 0..min_batch_size {
+                    v.push(&age as &dyn ToSql);
+                    v.push(&is_active as &dyn ToSql);
+                }
+                v
+            });
             stmt.execute(&*param_values).unwrap();
         }
     }