Insert queries take an enormous amount of time with replicas

[🦛]

tursoClient.js

import { createClient } from "@libsql/client"

const tursoClient = createClient({
  url: process.env.TURSO_DATABASE_URL,
  authToken: process.env.TURSO_AUTH_TOKEN,
})

export default tursoClient

app.js

import tursoClient from './lib/tursoClient.js'

async function testDB() {
    const iterations = 1000 // Number of iterations for stress testing

    // Variables to store performance metrics
    let totalQueryTime = 0
    let totalWriteTime = 0

    // Read operation
    for (let i = 0; i < iterations; i++) {
        const startQueryTime = Date.now()
        const employees = await tursoClient.execute("SELECT * FROM Employees")
        const endQueryTime = Date.now()
        totalQueryTime += endQueryTime - startQueryTime
    }

    // Write operation (inserting a new employee)
    for (let i = 0; i < iterations; i++) {
        const startWriteTime = Date.now()
        // Generate random data for the new employee
        const newEmployeeFirstName = await getRandomString()
        const newEmployeeLastName = await getRandomString()
        const newEmployeeDepartmentID = 1
        // Execute the INSERT query
        await tursoClient.execute({
            sql: "INSERT INTO Employees (FirstName, LastName, DepartmentID) VALUES (?, ?, ?)",
            args: [newEmployeeFirstName, newEmployeeLastName, newEmployeeDepartmentID]
        })
        const endWriteTime = Date.now()
        totalWriteTime += endWriteTime - startWriteTime
    }

    // Print performance reports
    const averageQueryTime = totalQueryTime / iterations
    console.log(`Average query time for SELECT operation: ${averageQueryTime} ms`)

    const averageWriteTime = totalWriteTime / iterations
    console.log(`Average time taken for INSERT operation: ${averageWriteTime} ms`)
}

async function getRandomString() {
  const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
  let randomString = ''
  for (let i = 0; i < 5; i++) {
    randomString += characters.charAt(Math.floor(Math.random() * characters.length))
  }
  return randomString
}

await testDB()

Results:

Primary only:

root@ubuntu-s-4vcpu-16gb-amd-ams3-01:~/pastebin# node --env-file=.env app.js 
Average query time for SELECT operation: 20.641 ms
Average time taken for INSERT operation: 19.172 ms

Primary + 2 replicas:

root@ubuntu-s-4vcpu-16gb-amd-ams3-01:~/pastebin# node --env-file=.env app.js 
Average query time for SELECT operation: 13.753 ms
Average time taken for INSERT operation: 132.646 ms

Is this acceptable? Is there a way to disable replication acknowledgment for insert operations, similar to MongoDB?

[Piotr Jastrzębski]

Replication is async so it shouldn't impact the performance. This is something we will have to debug to understand why replication has such a big impact on performance.