Dave Nolan textgoeshere

Finding a Ruby memory leak using a time analysis

When developing a program in Ruby, you may sometimes encounter a memory leak. For a while now, Ruby has a facility to gather information about what objects are laying around: ObjectSpace.

There are several approaches one can take to debug a leak. This discusses a time-based approach, where a full memory dump is generated every, say, 5 minutes, during a time that the memory leak is showing up. Afterwards, one can look at all the objects, and find out which ones are staying around, causing the

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Original (404'ed) -- https://plus.google.com/115094562986465477143/posts/Di6RwCNKCrf
Fakeout -- http://www.dzone.com/links/rss/ryan_dahl_i_hate_almost_all_software.html
Repost -- https://plus.google.com/116904230181415286707/posts/DnAMAN5sUR8

	This note explains how to build Postgres from source and setup to debug it using LLDB on a Mac. I used this technique to research this article:
	http://patshaughnessy.net/2014/10/13/following-a-select-statement-through-postgres-internals

	1. Shut down existing postgres if necessary - you don’t want to mess up your existing DB or work :)

	$ ps aux \| grep postgres
	pat 456 0.0 0.0 2503812 828 ?? Ss Sun10AM 0:11.59 postgres: stats collector process
	pat 455 0.0 0.0 2649692 2536 ?? Ss Sun10AM 0:05.00 postgres: autovacuum launcher process
	pat 454 0.0 0.0 2640476 304 ?? Ss Sun10AM 0:00.74 postgres: wal writer process
	pat 453 0.0 0.0 2640476 336 ?? Ss Sun10AM 0:00.76 postgres: writer process

	# Inspired by https://www.fpcomplete.com/user/dpiponi/the-mother-of-all-monads, A ruby port of Haskell's continuation monad, using fibers for lazily-evaluated giggles:
	#
	# For reference, The continuation monad instance definition from haskell:
	# instance Monad (Cont r) where
	# return a = Cont ($ a)
	# m >>= k = Cont $ \c -> runCont m $ \a -> runCont (k a) c

	#HI THERE, I AM THE CONTINUATION MONAD
	class Cont
	def self.unit(x)