hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

henrik

tmux cheatsheet

As configured in my dotfiles.

start new:

tmux

start new with session name:

leonardofed

A curated list of AWS resources to prepare for the AWS Certifications

A curated list of awesome AWS resources you need to prepare for the all 5 AWS Certifications. This gist will include: open source repos, blogs & blogposts, ebooks, PDF, whitepapers, video courses, free lecture, slides, sample test and many other resources.

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valyala

Optimizing postgresql table for more than 100K inserts per second

• Create UNLOGGED table. This reduces the amount of data written to persistent storage by up to 2x.
• Set WITH (autovacuum_enabled=false) on the table. This saves CPU time and IO bandwidth on useless vacuuming of the table (since we never DELETE or UPDATE the table).
• Insert rows with COPY FROM STDIN. This is the fastest possible approach to insert rows into table.
• Minimize the number of indexes in the table, since they slow down inserts. Usually an index on time timestamp with time zone is enough.
• Add synchronous_commit = off to postgresql.conf.
• Use table inheritance for fast removal of old data:

typehorror

Flask-SQLAlchemy Caching

The following gist is an extract of the article Flask-SQLAlchemy Caching. It allows automated simple cache query and invalidation of cache relations through event among other features.

Usage

retrieve one object

# pulling one User object

user = User.query.get(1)

abacaphiliac

Start Kafka service

The following commands will start a container with Kafka and Zookeeper running on mapped ports 2181 (Zookeeper) and 9092 (Kafka).

docker pull spotify/kafka
docker run -d -p 2181:2181 -p 9092:9092 --env ADVERTISED_HOST=kafka --env ADVERTISED_PORT=9092 --name kafka spotify/kafka

Why Spotify?

ADVERTISTED_HOST was set to kafka, which will allow other containers to be able to run Producers and Consumers.

jpillora

// A small SSH daemon providing bash sessions
//
// Server:
// cd my/new/dir/
// #generate server keypair
// ssh-keygen -t rsa
// go get -v .
// go run sshd.go
//
// Client:

Jaza

*

rgl

// see https://books.sonatype.com/nexus-book/3.0/reference/scripting.html
// see https://github.com/sonatype/nexus-book-examples/tree/nexus-3.0.x/scripting/nexus-script-example 

import groovy.json.JsonOutput
import org.sonatype.nexus.security.user.UserSearchCriteria
import org.sonatype.nexus.security.authc.apikey.ApiKeyStore
import org.sonatype.nexus.security.realm.RealmManager
import org.apache.shiro.subject.SimplePrincipalCollection
import org.sonatype.nexus.scheduling.TaskScheduler
import org.sonatype.nexus.scheduling.schedule.Daily