codesnips

performance

ruby 
module RequestStore
  def self.store
    Thread.current[:request_store] ||= {}
  end

  def self.fetch(key)

Hot Path Memoization (within request only)

rails performance memoization
by codesnips 4 tabs
go 
package api

import "net/http"

func ETag(w http.ResponseWriter, r *http.Request, etag string) bool {
  w.Header().Set("ETag", etag)

ETag handling for conditional GETs (cheap caching)

go http caching
by Leah Thompson 1 tab
ruby 
class CounterBuffer
  DELTA_HASH = "counter:deltas".freeze

  READ_RESET = <<~LUA.freeze
    local v = redis.call('HGET', KEYS[1], ARGV[1])
    if v then redis.call('HDEL', KEYS[1], ARGV[1]) end

Debounce Expensive Counter Cache Updates with a Throttled Redis Buffer in Rails

rails redis counter-cache
by codesnips 3 tabs
typescript 
import { useEffect, useState } from "react";

export function useDebouncedValue<T>(value: T, delay = 300): T {
  const [debounced, setDebounced] = useState<T>(value);

  useEffect(() => {

Build a Debounced Search Box in React with a Reusable useDebouncedValue Hook

react hooks typescript
by codesnips 3 tabs
python 
import hashlib
import json


def compute_etag(payload, weak=False):
    body = json.dumps(payload, sort_keys=True, separators=(",", ":"))

Conditional GET with ETag Generation and 304 Not Modified in Flask

flask http caching
by codesnips 3 tabs
ruby 
require 'activerecord-import'

class BulkImportPostsService
  BATCH_SIZE = 1000

  def initialize(csv_file_path)

Bulk operations with ActiveRecord import

rails performance activerecord
by Alex Kumar 1 tab
go 
package pipeline

import (
	"bufio"
	"errors"
	"io"

Stream and Transform a Large Log File Line-by-Line with bufio.Scanner

go streaming bufio
by codesnips 3 tabs
go 
package observability

import (
  "time"

  "go.uber.org/zap"

Sampling logs to reduce noise during high-QPS incidents

go logging observability
by Leah Thompson 1 tab
go 
package pricecache

import (
	"context"
	"sync"

Collapse Concurrent Identical Requests in Go with singleflight

go singleflight concurrency
by codesnips 3 tabs
ruby 
module QueryBudget
  class Counter
    IGNORED = %w[SCHEMA CACHE TRANSACTION].freeze

    attr_reader :count

Per-Request Query Budget (Detect Runaway Pages)

rails performance observability
by codesnips 4 tabs
sql 
CREATE TABLE events (
    id          bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    source      text        NOT NULL,
    external_id text        NOT NULL,
    payload     jsonb       NOT NULL,
    occurred_at timestamptz NOT NULL,

Batched writes with COPY (conceptual)

postgres performance sql
by codesnips 3 tabs
typescript 
import { useState } from 'react'
import { useQuery } from '@tanstack/react-query'
import { useDebounce } from '@/hooks/useDebounce'
import api from '@/services/api'

export function SearchInput() {

Debounced search with controlled inputs

react search debounce
by Maya Patel 1 tab