prasanthj

Build times for Apache Hive master on my Mac Book Pro

# No source code changes (first build not considered as mvn will download all dependencies and cache it locally)

# Base: Clean offline quite build
$ time mvn clean install -DskipTests -o -q
real	3m9.005s
user	7m14.864s
sys	0m40.295s

prasanthj

Notes to make IR shield (made by LinkSprite) work in Raspberry Pi 3 (bought from Amazon [1]). 
The vendor has some documentation [2] but that is not complete and sufficient for Raspbian Stretch. 
Following are the changes that I made to make it work.

$ sudo apt-get update
$ sudo apt-get install lirc

# Add the following lines to /etc/modules file
lirc_dev
lirc_rpi gpio_in_pin=18 gpio_out_pin=17

prasanthj

import json
import os,sys

class ATSFile(object):
	def __init__(self, name):
		self.data = json.load(open(name))
		self.name = name
	def dump(self):
		if "hive_query_id" in self.data:
			info = self.data["hive_query_id"]["otherinfo"]

prasanthj

$ cat .git/config
[core]
        repositoryformatversion = 0
        filemode = true
        bare = false
        logallrefupdates = true
        ignorecase = true
        precomposeunicode = true
[remote "origin"]
        url = https://git-wip-us.apache.org/repos/asf/orc.git

prasanthj

These are tunings from https://github.com/basho/leveldb
Video: https://www.youtube.com/watch?v=vo88IdglU_8

https://github.com/google/leveldb/blob/master/include/leveldb/options.h#L83
- write buffer size - default 4MB (increase this for higher performance) (try 10x or 100x will get 72% performance) 

https://github.com/google/leveldb/blob/master/db/skiplist.h#L98
- if increasing write buffer size, also increase skip list max height. Since skip list is probabilistic, 
expected number of keys in write buffer has to specified ahead. (change it from 2^12 to 2^17, affects read and write performance) 

prasanthj

# PDSH Usage
export PDSH_SSH_ARGS_APPEND="-q -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -i ~/.ssh/private.key"
pdsh -R ssh -w ^slaves.txt

# parallel-ssh Usage
parallel-ssh -x "-oStrictHostKeyChecking=no -i ~/.ssh/private.key" -i -h slaves.txt "sudo -u root jps | grep "LlapDaemon" | cut -f1 -d' '"

# remote heap-dump
# Add the following contents to jcmds.sh and use parallel-scp to copy the script to all hosts
#!/bin/bash

prasanthj

Enable native memory tracking in JVM by specifying the following flag

-XX:NativeMemoryTracking=detail

Know the <PID> of the java process

jps

To print ps based RSS

ps -p <PID> -o pcpu,rss,size,vsize

To print native memory tracking summary

prasanthj

-- hot reload init.lua script
function reloadConfig(files)
    doReload = false
    for _,file in pairs(files) do
        if file:sub(-4) == ".lua" then
            doReload = true
        end
    end
    if doReload then
        hs.reload()

prasanthj

set vpn_name to "'VPN_NAME'"

tell application "System Events"
	set rc to do shell script "scutil --nc status " & vpn_name
	if rc starts with "Connected" then
		do shell script "scutil --nc stop " & vpn_name
	else
		-- get current clipboard contents as a string
		set CurrentClipboard to the clipboard as string
		

prasanthj

# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#