From 44201814b9c3fa744670d26abf2271896e15d114 Mon Sep 17 00:00:00 2001
From: Conrad Ludgate <conrad@neon.tech>
Date: Thu, 17 Jul 2025 10:11:30 +0100
Subject: [PATCH] add benchmark for json str escaping

---
 Cargo.lock                        |  1 +
 libs/postgres_ffi/Cargo.toml      |  2 +-
 libs/proxy/json/Cargo.toml        |  5 ++++
 libs/proxy/json/benches/escape.rs | 50 +++++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 libs/proxy/json/benches/escape.rs

diff --git a/Cargo.lock b/Cargo.lock
index 137b883a6d..c476a00abe 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3507,6 +3507,7 @@ dependencies = [
 name = "json"
 version = "0.1.0"
 dependencies = [
+ "criterion",
  "futures",
  "itoa",
  "ryu",
diff --git a/libs/postgres_ffi/Cargo.toml b/libs/postgres_ffi/Cargo.toml
index d4fec6cbe9..9ef8a5b13f 100644
--- a/libs/postgres_ffi/Cargo.toml
+++ b/libs/postgres_ffi/Cargo.toml
@@ -9,7 +9,6 @@ regex.workspace = true
 bytes.workspace = true
 anyhow.workspace = true
 crc32c.workspace = true
-criterion.workspace = true
 once_cell.workspace = true
 log.workspace = true
 memoffset.workspace = true
@@ -22,6 +21,7 @@ tracing.workspace = true
 postgres_versioninfo.workspace = true
 
 [dev-dependencies]
+criterion.workspace = true
 env_logger.workspace = true
 postgres.workspace = true
 
diff --git a/libs/proxy/json/Cargo.toml b/libs/proxy/json/Cargo.toml
index 2f163c141d..a6424f868f 100644
--- a/libs/proxy/json/Cargo.toml
+++ b/libs/proxy/json/Cargo.toml
@@ -10,3 +10,8 @@ itoa = "1"
 
 [dev-dependencies]
 futures = "0.3"
+criterion.workspace = true
+
+[[bench]]
+name = "escape"
+harness = false
diff --git a/libs/proxy/json/benches/escape.rs b/libs/proxy/json/benches/escape.rs
new file mode 100644
index 0000000000..17dfe6b4c5
--- /dev/null
+++ b/libs/proxy/json/benches/escape.rs
@@ -0,0 +1,50 @@
+use std::hint::black_box;
+
+use criterion::{Bencher, Criterion, criterion_group, criterion_main};
+
+#[derive(Debug)]
+#[allow(dead_code)]
+struct Foo {
+    some_field: Bar,
+    some_other_field: String,
+}
+
+#[derive(Debug)]
+#[allow(dead_code)]
+struct Bar {
+    nested_fields: String,
+    some_other_value: i32,
+}
+
+pub fn escape(c: &mut Criterion) {
+    c.bench_function("small", |b| bench_json_encode_inner(b, "object_key"));
+    c.bench_function("large_fmt", |b| {
+        let value = Foo {
+            some_field: Bar {
+                nested_fields: "could not connect to database, control plane error \"foo bar\""
+                    .to_string()
+                    .to_string(),
+                some_other_value: -1,
+            },
+            some_other_field: "error".to_string(),
+        };
+
+        bench_json_encode_inner(b, format_args!("{:?}", &value));
+    });
+}
+
+criterion_group!(benches, escape);
+criterion_main!(benches);
+
+fn bench_json_encode_inner(b: &mut Bencher<'_>, v: impl json::ValueEncoder + Copy) {
+    let mut output = Vec::new();
+
+    // write it once so we don't alloc during the benchmark.
+    json::ValueSer::new(&mut output).value(black_box(v));
+
+    b.iter(|| {
+        output.clear();
+        json::ValueSer::new(&mut output).value(black_box(v));
+        black_box(&output[..]);
+    });
+}