Mark von Minden mrkvm

Fills a single table and launches several goroutines to do concurrent SELECT operations.

We are running this on a fairly beefy machine with 24 CPUs and can reproduce the issue fairly quickly with the parameters in the test. Output file is also attached with the crash.

Here's our environment:

[root@flash1 sqlitetest]# go version
go version devel +8153882a36e8 Wed Apr 03 11:13:40 2013 -0700 linux/amd64

[root@flash1 sqlitetest]# go env

	benchmark old ns/op new ns/op delta
	BenchmarkHeaderWriteSubset 1925 2241 +16.42%
	BenchmarkReadRequestChrome 10393 12791 +23.07%
	BenchmarkReadRequestCurl 5424 6398 +17.96%
	BenchmarkReadRequestApachebench 5145 6348 +23.38%
	BenchmarkReadRequestSiege 7212 8892 +23.29%
	BenchmarkReadRequestWrk 3428 4220 +23.10%
	BenchmarkClientServer 90999 8016844 +8709.82%
	BenchmarkClientServerParallel4 81917 2027296 +2374.82%
	BenchmarkClientServerParallel64 76994 200184 +160.00%

	require 'redis'

	class TrickOrTreatTracker
	def initialize
	@redis = Redis.new
	end

	def track_trick(user_id)
	key = "trick-#{Time.now.hour}"
	@redis.setbit key, user_id, 1

	require 'redis'

	# Lua script to set a Redis key if it doesn't exist yet.
	# Returns result of SET if key is not set, otherwise
	# returns the previous value of the key.
	SetScript = <<EOF
	local val = redis.call('GET', KEYS[1])
	if val == false then
	return redis.call('SET', KEYS[1], ARGV[1])
	end

	require 'redis'

	# Simple Lua script to set all the given keys to the given values.
	# Note the magic of this is that it's done atomically. Yay atomicity!
	MultiSetScript = <<EOF
	for i = 1, #KEYS do
	redis.call('SET', KEYS[i], ARGV[i])
	end
	EOF

	-- Get a key containing JSON in Redis
	local key = KEYS[1];
	local name = ARGV[1];

	local data = redis.call('GET', key);

	if not data then
	return '';
	else
	local json = cjson.decode(redis.call('GET', key));

	-- Set a key containing JSON in Redis
	local key = KEYS[1];
	local name = ARGV[1];
	local value = ARGV[2];

	local data = redis.call('GET', key);
	local json;

	if not data then
	json = {};

	-- iterate over Redis hash in Lua.
	local results = redis.call("HGETALL", KEYS[1]);
	if results ~= 0 then
	for key, value in ipairs(results) do
	-- do something here
	end
	end

	# Redis PUB/SUB example:

	# client 1:
	redis 127.0.0.1:6379> subscribe beartalk
	Reading messages... (press Ctrl-C to quit)
	1) "subscribe"
	2) "beartalk"
	3) (integer) 1

	# ...wait around for message...

	source :gemcutter
	gem 'pit'
	gem 'sauberia-aws-s3'