From f392bcd9885d52c39fb6de2efdac4de03171aeb3 Mon Sep 17 00:00:00 2001
From: Lev Kokotov <lev.kokotov@gmail.com>
Date: Fri, 16 Jan 2026 08:50:38 -0800
Subject: [PATCH] Race condition search

---
 integration/fast_write_read/.gitignore   |   2 +
 integration/fast_write_read/README.md    |   6 ++
 integration/fast_write_read/index.js     | 120 +++++++++++++++++++++++
 integration/fast_write_read/package.json |  13 +++
 integration/fast_write_read/pgdog.toml   |   6 ++
 integration/fast_write_read/users.toml   |   4 +
 6 files changed, 151 insertions(+)
 create mode 100644 integration/fast_write_read/.gitignore
 create mode 100644 integration/fast_write_read/README.md
 create mode 100644 integration/fast_write_read/index.js
 create mode 100644 integration/fast_write_read/package.json
 create mode 100644 integration/fast_write_read/pgdog.toml
 create mode 100644 integration/fast_write_read/users.toml

diff --git a/integration/fast_write_read/.gitignore b/integration/fast_write_read/.gitignore
new file mode 100644
index 00000000..504afef8
--- /dev/null
+++ b/integration/fast_write_read/.gitignore
@@ -0,0 +1,2 @@
+node_modules/
+package-lock.json
diff --git a/integration/fast_write_read/README.md b/integration/fast_write_read/README.md
new file mode 100644
index 00000000..ca4c8b6a
--- /dev/null
+++ b/integration/fast_write_read/README.md
@@ -0,0 +1,6 @@
+# Race condition search
+
+1. `cd` into this directory.
+2. In psql, run `CREATE DATABASE pgdog`, `CREATE USER pgdog PASSWORD 'pgdog' LOGIN` (if not exists already).
+3. `cargo run --release --bin pgdog` (release is faster, helps find race condtions).
+4. In a different terminal, run `npm start`.
diff --git a/integration/fast_write_read/index.js b/integration/fast_write_read/index.js
new file mode 100644
index 00000000..6119e3de
--- /dev/null
+++ b/integration/fast_write_read/index.js
@@ -0,0 +1,120 @@
+import { Sequelize, DataTypes } from "sequelize";
+
+const sequelize = new Sequelize("postgres://pgdog:pgdog@127.0.0.1:6432/pgdog", {
+  logging: false,
+  disableClsTransactions: true,
+  dialectOptions: {
+    autocommit: true,
+  },
+  pool: {
+    max: 20,
+    min: 20,
+    acquire: 60000,
+    idle: 10000,
+  },
+});
+
+const Author = sequelize.define("Author", {
+  id: {
+    type: DataTypes.INTEGER,
+    primaryKey: true,
+    autoIncrement: true,
+  },
+  name: {
+    type: DataTypes.STRING,
+    allowNull: false,
+  },
+});
+
+const Book = sequelize.define("Book", {
+  id: {
+    type: DataTypes.INTEGER,
+    primaryKey: true,
+    autoIncrement: true,
+  },
+  title: {
+    type: DataTypes.STRING,
+    allowNull: false,
+  },
+  authorId: {
+    type: DataTypes.INTEGER,
+    allowNull: false,
+    references: {
+      model: Author,
+      key: "id",
+    },
+  },
+});
+
+Author.hasMany(Book, { foreignKey: "authorId" });
+Book.belongsTo(Author, { foreignKey: "authorId" });
+
+async function insertAuthorAndBook(i) {
+  const author = await Author.create({ name: `Author ${i}` });
+  const book = await Book.create({ title: `Book ${i}`, authorId: author.id });
+  return { author, book };
+}
+
+async function main() {
+  await sequelize.sync({ force: true });
+
+  const iterations = 500000;
+  const batchSize = 1000;
+
+  console.log(`Starting ${iterations} insert pairs in batches of ${batchSize} (pool: 20)`);
+
+  let completed = 0;
+  let errors = 0;
+  const errorDetails = {};
+  const start = Date.now();
+
+  for (let batch = 0; batch < iterations; batch += batchSize) {
+    const batchEnd = Math.min(batch + batchSize, iterations);
+    const promises = [];
+
+    for (let i = batch; i < batchEnd; i++) {
+      promises.push(
+        insertAuthorAndBook(i)
+          .then(() => {
+            completed++;
+          })
+          .catch((err) => {
+            errors++;
+            const key = err.message.substring(0, 60);
+            errorDetails[key] = (errorDetails[key] || 0) + 1;
+            if (errors <= 10) {
+              console.error(`Error on iteration ${i}: ${err.message}`);
+            }
+          }),
+      );
+    }
+
+    await Promise.allSettled(promises);
+
+    const elapsed = ((Date.now() - start) / 1000).toFixed(1);
+    const rate = (completed / (Date.now() - start) * 1000).toFixed(0);
+    console.log(`Batch ${batch / batchSize + 1}: ${completed}/${iterations} (${elapsed}s, ${rate}/s, errors: ${errors})`);
+  }
+
+  const elapsed = ((Date.now() - start) / 1000).toFixed(1);
+  console.log(`\nFinished in ${elapsed}s`);
+  console.log(`Results: Completed: ${completed}, Errors: ${errors}`);
+
+  if (Object.keys(errorDetails).length > 0) {
+    console.log("Error breakdown:");
+    for (const [msg, count] of Object.entries(errorDetails)) {
+      console.log(`  ${msg}...: ${count}`);
+    }
+  }
+
+  const authorCount = await Author.count();
+  const bookCount = await Book.count();
+  console.log(`Authors: ${authorCount}, Books: ${bookCount}`);
+
+  await sequelize.close();
+}
+
+main().catch((err) => {
+  console.error(err);
+  process.exit(1);
+});
diff --git a/integration/fast_write_read/package.json b/integration/fast_write_read/package.json
new file mode 100644
index 00000000..bee2d105
--- /dev/null
+++ b/integration/fast_write_read/package.json
@@ -0,0 +1,13 @@
+{
+  "name": "fast_write_read",
+  "version": "1.0.0",
+  "type": "module",
+  "main": "index.js",
+  "scripts": {
+    "start": "node index.js"
+  },
+  "dependencies": {
+    "pg": "^8.14.1",
+    "sequelize": "^6.37.5"
+  }
+}
diff --git a/integration/fast_write_read/pgdog.toml b/integration/fast_write_read/pgdog.toml
new file mode 100644
index 00000000..48a87f5d
--- /dev/null
+++ b/integration/fast_write_read/pgdog.toml
@@ -0,0 +1,6 @@
+[[databases]]
+name = "pgdog"
+host = "127.0.0.1"
+
+[admin]
+password = "pgdog"
diff --git a/integration/fast_write_read/users.toml b/integration/fast_write_read/users.toml
new file mode 100644
index 00000000..581cdb75
--- /dev/null
+++ b/integration/fast_write_read/users.toml
@@ -0,0 +1,4 @@
+[[users]]
+name = "pgdog"
+database = "pgdog"
+password = "pgdog"