frsyuki

My thoughts on MessagePack

Hi. My name is Sadayuki "Sada" Furuhashi. I am the author of the MessagePack serialization format as well as its implementation in C/C++/Ruby.

Recently, MessagePack made it to the front page of Hacker News with this blog entry by Olaf, the creator of the Facebook game ZeroPilot. In the comment thread, there were several criticisms for the blog post as well as MessagePack itself, and I thought this was a good opportunity for me to address the questions and share my thoughts.

My high-level response to the comments

To the best of my understanding, roughly speaking, the criticisms fell into the following two categories.

andreyvit

tmux cheat sheet

(C-x means ctrl+x, M-x means alt+x)

Prefix key

The default prefix is C-b. If you (or your muscle memory) prefer C-a, you need to add this to ~/.tmux.conf:

remap prefix to Control + a

rgreenjr

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

mattratleph

vimdiff cheat sheet

##git mergetool

In the middle file (future merged file), you can navigate between conflicts with ]c and [c.

Choose which version you want to keep with :diffget //2 or :diffget //3 (the //2 and //3 are unique identifiers for the target/master copy and the merge/branch copy file names).

:diffupdate (to remove leftover spacing issues)

:only (once you’re done reviewing all conflicts, this shows only the middle/merged file)

willurd

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

macintux

This is not intended to be comprehensive or authoritative, just free online resources I've found valuable while learning more about Erlang.

Similar lists

• 0xAX's list of Erlang bookmarks
• Federico Carrone, Erlang Spawned Shelter
• Ivan Uemlianin's list of resources on various BEAM languages
• David Robakowski's curated list of awesome Erlang libraries, resources and shiny things
• Julius Beckmann's curated list of amazingly awesome Elixir and Erlang libraries, resources and shiny things

Instruction

chanks

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

rajanand02

# set prefix to control-f
set -g prefix C-f

#unbind system defined prefix
unbind C-b

# helps in faster key repetition
set -sg escape-time 0

# start session number from 1 rather than 0

Kartones

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

• -E: will describe the underlaying queries of the \ commands (cool for learning!)
• -l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

marcellodesales

rm -f out
mkfifo out
trap "rm -f out" EXIT
while true
do
  cat out | nc -w1 -l 1500 > >( # parse the netcat output, to build the answer redirected to the pipe "out".
    export REQUEST=
    while read line
    do
      line=$(echo "$line" | tr -d '[\r\n]')