codesnips

batching

ruby 
class ReindexCheckpoint < ApplicationRecord
  enum status: { idle: 0, running: 1, done: 2, failed: 3 }

  validates :index_name, presence: true, uniqueness: true

  def self.for(index_name)

Safer Background Reindex: slice batches + checkpoints

rails reliability elasticsearch
by codesnips 4 tabs
typescript 
import { onCLS, onINP, onLCP, onFCP, onTTFB, type Metric } from 'web-vitals';

export interface VitalPayload {
  id: string;
  name: Metric['name'];
  value: number;

Web Vitals reporting to an API endpoint

performance observability react
by codesnips 3 tabs
typescript 
import DataLoader from "dataloader";
import { Pool } from "pg";

export interface User { id: number; name: string; }
export interface Post { id: number; user_id: number; title: string; }

N+1 avoidance with DataLoader (GraphQL)

graphql performance dataloader
by codesnips 3 tabs
ruby 
class Order < ApplicationRecord
  belongs_to :customer

  scope :for_export, -> {
    select(:id, :reference, :total_cents, :currency, :created_at, :customer_id)
      .where.not(exported_at: nil)

Avoid Memory Blowups: find_each + select Columns

rails activerecord performance
by codesnips 3 tabs
ruby 
class Post < ApplicationRecord
  has_many :comments, dependent: :destroy

  # comments_count is maintained by counter_cache on Comment#belongs_to

  scope :stale_comment_counts, lambda {

Counter Cache Repair Job (Consistency Tooling)

rails activerecord counter-cache
by codesnips 3 tabs
typescript 
import { Writable } from "node:stream";
import type { Pool } from "pg";

interface Row {
  email: string;
  name: string;

Streaming CSV import (Node streams)

streams postgres nodejs
by codesnips 3 tabs
ruby 
class AddSoftDeleteToDocuments < ActiveRecord::Migration[7.0]
  disable_ddl_transaction!

  def change
    add_column :documents, :marked_for_deletion_at, :datetime, null: true

Safer Time-Based Deletes with “mark then sweep”

rails reliability activerecord
by codesnips 4 tabs
ruby 
module Notifications
  class RecipientSerializer < ActiveJob::Serializers::ObjectSerializer
    def serialize?(argument)
      argument.is_a?(Notifications::Recipient)
    end

Enqueuing Notification Batches with a Custom Active Job Argument Serializer for Value Objects

rails active-job serialization
by codesnips 4 tabs
sql 
-- Step 1: add the column nullable, no default.
-- Catalog-only change in Postgres 11+, returns instantly.
ALTER TABLE orders
  ADD COLUMN currency text;

-- Optional: keep the lock attempt bounded so a long-running

SQL migration safety: add column nullable, backfill, then constrain

postgres migrations reliability
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
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 watch

import (
	"sync"
	"time"
)

Debounce Filesystem Change Events Before Triggering a Rebuild in Go

fsnotify debounce filewatcher
by codesnips 3 tabs