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

andrequeiroz

#The MIT License (MIT)
#
#Copyright (c) 2015 Andre Queiroz
#
#Permission is hereby granted, free of charge, to any person obtaining a copy
#of this software and associated documentation files (the "Software"), to deal
#in the Software without restriction, including without limitation the rights
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#copies of the Software, and to permit persons to whom the Software is
#furnished to do so, subject to the following conditions:

smintz

#!/bin/bash
SOURCEINSTANCE=${SOURCEINSTANCE:-''}
SOURCEUSER=${SOURCEUSER:-'admin'}
SOURCEPORT=${SOURCEPORT:-'5439'}
SOURCEDB=${SOURCEDB:-'db'}
SOURCESCHEMA=${SOURCESCHEMA:-'public'}
SCHEMA=${SCHEMA:-'public'}
  echo  "CREATE TABLE ${SCHEMA}.${TABLE} ("
  psql -h ${SOURCEINSTANCE} -U ${SOURCEUSER} -p ${SOURCEPORT} ${SOURCEDB} -t -c "select (\"column\" || ' ' || type || ' ENCODE ' || encoding || ',' ) from pg_table_def where schemaname='$SCHEMA' and tablename = '$TABLE'" | sed 's/ENCODE none/ENCODE RAW/' | sed '$d' | sed '$ s/,$//'
  echo ")"

frsyuki

Presto connector development 1

One of the very good design decisions Presto designers made is that it's loosely coupled from storages.

Presto is a distributed SQL executor engine, and doesn't manager schema or metadata of tables by itself. It doesn't manage read data from storage by itself. Those businesses are done by plugins called Connector. Presto comes with Hive connector built-in, which connects Hive's metastore and HDFS to Presto.

We can connect any storages into Presto by writing connector plugins.

Plugin Architecture

electrum

See https://github.com/facebook/presto/wiki/HTTP-Protocol

voluntas

時雨堂コトハジメ

更新:	2024-05-22
作者:	@voluntas
バージョン:	2024.1
URL:	https://voluntas.github.io/

typo などは https://x.com/voluntas までご連絡ください。

frsyuki

import os
import json
import httplib
import time

VERSION = "0.1.0"

class ClientSession:
    def __init__(self, server, user, source=None, catalog=None, schema=None, debug=False):
        self.server = server

yangliuyu

sudo yum install jdk-7u65-linux-x64.rpm
sudo yum install gcc
sudo yum install gcc-gfortran
sudo yum install blas lapack arpack

unzip netlib-java-1.1.2.zip
cd ~/netlib-java-1.1.2
sed -i "s/1.2-SNAPSHOT/1.1.2/g" `grep -rl 1.2-SNAPSHOT .`
mvn install
cd native_system/

sebsto

sudo wget http://repos.fedorapeople.org/repos/dchen/apache-maven/epel-apache-maven.repo -O /etc/yum.repos.d/epel-apache-maven.repo
sudo sed -i s/\$releasever/6/g /etc/yum.repos.d/epel-apache-maven.repo
sudo yum install -y apache-maven
mvn --version

komiya-atsushi

import java.io.PrintStream;
import java.util.Base64;

/**
 * Java 8 より導入された java.util.Base64 の利用デモ。
 */
public class Base64Demo {
    private static final PrintStream o = System.out;

    public static void main(String[] args) {