Junil Jacob JunilJacob

In my application every time I send a newsletter to a User, I create a NewsletterDelivery record. I frequently want to be able to query, for each user, what is the most recent newsletter delivery record. This is called a "last n per group" query and a LATERAL JOIN is the best way to do it imo. But the query I've been using (and I've told people to use, and seen blogged about) is not very good, because the conditions don't get pushed down into the subselect which means that the query ends-up lateral-joining all the records before it applies the conditions for the association.

Instead of doing subselect_table.* the better query does association.id AS assocation_id, subselect_table.id, subselect_table.title, .... and enumerates over all of the columns. This allows the association query, which Active Record tacks on at the end as WHERE association_id = $1 or WHERE association_id IN ($1, $2, $3, ...) to be pushed down c

	module Retriable
	# This will catch any exception and retry twice (three tries total):
	# with_retries { ... }
	#
	# This will catch any exception and retry four times (five tries total):
	# with_retries(:limit => 5) { ... }
	#
	# This will catch a specific exception and retry once (two tries total):
	# with_retries(Some::Error, :limit => 2) { ... }
	#

	# unicorn_rails -c /data/github/current/config/unicorn.rb -E production -D

	rails_env = ENV['RAILS_ENV'] \|\| 'production'

	# 16 workers and 1 master
	worker_processes (rails_env == 'production' ? 16 : 4)

	# Load rails+github.git into the master before forking workers
	# for super-fast worker spawn times
	preload_app true

	module OneTimePassword
	# Concern containing logic and methods for OTP authentication.
	# Is used Time-based One-time Password Algorithm(TOTP)
	# https://tools.ietf.org/html/rfc6238
	extend ActiveSupport::Concern

	OTP_DIGITS = 6
	OTP_NUMBER_OF_BACKUP_CODES = 10
	OTP_BACKUP_CODE_LENGTH = 12

	#!/bin/bash
	for i in $( git tag -l \| grep staging ); do
	echo Tag: $i
	#git tag -d $i
	#git push origin :refs/tags/$i
	done

Junil Jacob JunilJacob

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