codesnips

postgres

ruby 
class CreateOutboxEvents < ActiveRecord::Migration[7.1]
  def change
    create_table :outbox_events do |t|
      t.string :event_type, null: false
      t.string :aggregate_type, null: false
      t.string :aggregate_id, null: false

Transactional Outbox for Reliable Event Publishing

rails background-jobs reliability
by codesnips 4 tabs
go 
package store

import (
  "context"
  "database/sql"
)

db/sql prepared statements with context and explicit Close

go sql postgres
by Leah Thompson 1 tab
typescript 
import { Prisma, PrismaClient } from "@prisma/client";

const prisma = new PrismaClient();

type TxClient = Prisma.TransactionClient;

Prisma transaction with retries for serialization errors

prisma postgres concurrency
by codesnips 3 tabs
python 
from alembic import op
import sqlalchemy as sa

revision = "20240612_add_status"
down_revision = "20240515_create_orders"
branch_labels = None

Zero-Downtime NOT NULL Column Backfill with Alembic and SQLAlchemy

alembic sqlalchemy migrations
by codesnips 2 tabs
ruby 
class LastSeenTracker
  THROTTLE = 5.minutes
  PENDING_KEY = "pending:last_seen".freeze

  class << self
    def touch(user_id, at: Time.current)

Database “Last Seen” without Hot Row Updates

rails performance redis
by codesnips 3 tabs
java 
package com.example.catalog.web;

import com.example.catalog.domain.Product;
import java.math.BigDecimal;

public record ProductResponse(

Paginated Product Search Endpoint with Spring Data JPA Specifications

spring-boot spring-data-jpa pagination
by codesnips 4 tabs
ruby 
class CreateReservations < ActiveRecord::Migration[7.1]
  def up
    enable_extension "btree_gist" unless extension_enabled?("btree_gist")

    create_table :reservations do |t|
      t.references :room, null: false, foreign_key: true

DB-Level “no overlapping ranges” with exclusion constraint

rails postgres exclusion-constraint
by codesnips 3 tabs
rust 
use sqlx::PgPool;
use std::time::Duration;
use tokio::sync::mpsc;

#[derive(Debug, Clone)]
pub struct MetricPoint {

Batching Database Writes in Rust with a Size- and Interval-Triggered Flush Buffer

rust tokio sqlx
by codesnips 3 tabs
go 
package bank

import "errors"

var ErrVersionConflict = errors.New("optimistic lock: version conflict")
var ErrInsufficientFunds = errors.New("insufficient funds")

Optimistic Locking in Go With a Version Column on UPDATE

optimistic-locking concurrency postgres
by codesnips 3 tabs
ruby 
class DashboardMetrics
  include ActiveModel::Model

  attr_reader :account

  def initialize(account)

Expiring Dashboard Fragment Caches with a Versioned Composite Cache Key in Rails

rails caching fragment-caching
by codesnips 3 tabs
javascript 
const MAX_LIMIT = 100;
const DEFAULT_LIMIT = 20;
const ALLOWED_ORDER = new Set(['asc', 'desc']);

function decodeCursor(raw) {
  const json = Buffer.from(raw, 'base64').toString('utf8');

Cursor-Based Pagination in Express With Query-Parsing Middleware

express pagination cursor-pagination
by codesnips 3 tabs
sql 
CREATE TYPE outbox_status AS ENUM ('pending', 'retry', 'processing', 'done', 'dead');

CREATE TABLE outbox_events (
    id           BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    dedupe_key   TEXT        NOT NULL,
    topic        TEXT        NOT NULL,

Atomic “Read + Mark Processed” with UPDATE … RETURNING

postgres concurrency reliability
by codesnips 3 tabs