tpdn

Service パターン
Builder パターン
Command パターン
- Shell
- Wrapper/Bundler

Websocketのロードバランス戦略

問題

websocketに対応していないロードバランサを使うといくつか問題が起きる

upgradeヘッダを捨ててしまい接続できない（L7スイッチなど）
ポート番号枯渇により新規接続ができなくなる
タイムアウトの設定が短いと定期的に切断されてしまう

Turning PostgreSQL into a queue serving 10,000 jobs per second

RDBMS-based job queues have been criticized recently for being unable to handle heavy loads. And they deserve it, to some extent, because the queries used to safely lock a job have been pretty hairy. SELECT FOR UPDATE followed by an UPDATE works fine at first, but then you add more workers, and each is trying to SELECT FOR UPDATE the same row (and maybe throwing NOWAIT in there, then catching the errors and retrying), and things slow down.

On top of that, they have to actually update the row to mark it as locked, so the rest of your workers are sitting there waiting while one of them propagates its lock to disk (and the disks of however many servers you're replicating to). QueueClassic got some mileage out of the novel idea of randomly picking a row near the front of the queue to lock, but I can't still seem to get more than an an extra few hundred jobs per second out of it under heavy load.

So, many developers have started going straight t

時雨堂を支える技術

日時:	2025-05-13
作:	時雨堂
バージョン:	2025.3
URL:	https://shiguredo.jp/

言語

	__author__ = 'KIM_TPDN'
	from logitechlcd import LogitechLcd
	from time import sleep

	if __name__ == '__main__':
	lcd = LogitechLcd('朝鮮民主主義人民共和国')
	lcd.set_text(0, '文字数は全角1文字=半角2文字')
	lcd.set_text(1, '換算で、1行あたり半角29文字')
	lcd.set_text(2, '文字数が一定を超えるとはみ出る')
	lcd.set_text(3, '김정일 【ﾊﾝｸﾞﾙ対応】金正日')

	import select
	import datetime

	import psycopg2
	import psycopg2.extensions

	from sqlalchemy import create_engine, text

	engine = create_engine("postgresql+psycopg2://vagrant@/postgres")

	Olympus Share APP control urls over E-M10 camera, still to investigate..

	http://192.168.0.10
	http://192.168.0.10/
	http://192.168.0.10/clear_resvflg.cgi
	http://192.168.0.10/exec_pwoff.cgi
	http://192.168.0.10/exec_shutter.cgi?com=1st2ndpush
	http://192.168.0.10/exec_shutter.cgi?com=1stpush
	http://192.168.0.10/exec_shutter.cgi?com=1strelease
	http://192.168.0.10/exec_shutter.cgi?com=2nd1strelease

	#!/bin/sh

	if git rev-parse --verify HEAD >/dev/null 2>&1
	then
	against=HEAD
	else
	# Initial commit: diff against an empty tree object
	against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
	fi

	from datetime import datetime
	from sqlalchemy import Column, Integer, DateTime, ForeignKey
	from sqlalchemy.orm import relationship
	from sqlalchemy.ext.declarative import declared_attr
	from flask_security import current_user


	class AuditMixin(object):
	created_at = Column(DateTime, default=datetime.now)
	updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)

	Notes on how to use AWS SNS:

	1. Subscribe an HTTP endpoint (i.e. http://myhost/sns_endpoint) on AWS Console
	2. AWS will send subscription confirmation right away
	3. SNS_controller responds to subscription confirmation by sending confirmation using Fog.
	4. Once AWS is happy, you can start sending notifications to your end point via SNS.