Salvatore Sanfilippo antirez

Computer programmer based in Sicily, Italy. I mostly write OSS software. Born 1977. Not a puritan.

antirez / gist:284789

Created January 23, 2010 21:00

	./redis-stat vmpage samplesize 10000
	Sampling 10000 random keys from DB 0...
	Average serialized value size is: 12
	Simulate fragmentation with different page sizes
	8: bytes per page: 4.75, space efficiency: 59.38%
	16: bytes per page: 10.18, space efficiency: 63.60%
	32: bytes per page: 12.10, space efficiency: 37.81%
	64: bytes per page: 12.05, space efficiency: 18.83%
	128: bytes per page: 12.06, space efficiency: 9.43%
	256: bytes per page: 12.09, space efficiency: 4.72%

antirez / dramerr.c

Created February 5, 2010 23:29

	/* The following is a simple program to check for memory corrections in
	* DRAM with ECC switched off. Accordingly to recend large scale studies
	* such as http://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf
	* the error rate is of 25,000-75,000 errors per billion hours per Mbit.
	*
	* If this is true you should see at least one error after a few days
	* running this program at max in a computer without ECC.
	*
	* Compile with: gcc -O2 -Wall -W -o dramerr dramerr.c
	*

antirez / gist:296761

Created February 6, 2010 15:27

antirez / hash_memory_test.rb

Created March 7, 2010 22:39

	require 'rubygems'
	require 'redis'

	r = Redis.new
	(0..100000).each{\|i\|
	["name","surname","age","sex","password"].each{\|field\|
	if false
	r.set("obj#{i}#{field}","foo")
	else
	r.hset("obj#{i}",field,"foo")

antirez / gist:342183

Created March 24, 2010 11:09

	# We want to create our new object, and make sure it is in the Set of existing objects.
	1) INCR object.nextid => 1000 # Get an unique ID for the next object
	2) SET object:1000 "my object value" # Set the value of the object
	3) SADD all.my.objects 1000 # Add the ID of the object to the target Set, representing all the objects

	What happens if the client dies between 2 and 3? We have the object key, but "leaked" it forever as it's no longer in Set of our objects.

	MULTI/EXEC fix this problem:

	1) INCR object:nextid => 1000

antirez / gist:346913

Created March 28, 2010 17:53

antirez / fake-subscribers.tcl

Created April 1, 2010 16:29

	set numclients 50
	set ::reads 0

	for {set i 0} {$i < $numclients} {incr i} {
	set fd [socket 127.0.0.1 6379]
	fconfigure $fd -translation binary -blocking 0
	set ::client($i) $fd
	puts -nonewline $fd "SUBSCRIBE foo\r\n"
	flush $fd
	fileevent $fd readable [list discardData $fd]

antirez / gist:372356

Created April 20, 2010 12:13

antirez / gist:379653

Created April 26, 2010 17:55

	BEFORE:

	redis> set foo "hello world"
	Wrong number of arguments for 'set'

	$ cat /bin/ls \| ./redis-cli set x
	OK
	$ ./redis-cli
	redis> substr x 0 1023
	ELF>�&@@0�@8 @@@@@@�88@8@@@T�T� ��a�aP��a�TT@T@DDP�td0�0�A0�AttQ�tR�td��a�a >k2KQM$E81B[aO._Ph)Z-!G,`J 7TRmGNUd�k{�L�:ٔ�I�E^�&�aoNc W\*fbel3FSjY^]DCX

antirez / gist:383986

Created April 29, 2010 18:16