robsmith1776

#Systemd - How to read live-tail logs of multiple services with journalctl

sudo journalctl --follow _SYSTEMD_UNIT=docker.service + _SYSTEMD_UNIT=apache2.service

robsmith1776

FROM python:3-alpine

# install requirements for psycopg2
RUN apk update && apk add -u \
    postgresql-dev \
    gcc \
    python3-dev \
    musl-dev

RUN pip3 install psycopg2

robsmith1776

Mac install Nerd Font (Fire code)

brew cask
brew tap homebrew/cask-fonts 
brew install font-fira-code
brew install font-Fira-Code-nerd-font
brew install font-hack-nerd-font

robsmith1776

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:

robsmith1776

// Convert Javascript date to Pg YYYY MM DD HH MI SS

function pgFormatDate(date) {
  /* Via http://stackoverflow.com/questions/3605214/javascript-add-leading-zeroes-to-date */
  function zeroPad(d) {
    return ("0" + d).slice(-2)
  }

  var parsed = new Date(date)

robsmith1776

with table_stats as (
select psut.relname,
  psut.n_live_tup,
  1.0 * psut.idx_scan / greatest(1, psut.seq_scan + psut.idx_scan) as index_use_ratio
from pg_stat_user_tables psut
order by psut.n_live_tup desc
),
table_io as (
select psiut.relname,
  sum(psiut.heap_blks_read) as table_page_read,

robsmith1776

require 'pg'
db = PG.connect dbname: 'postgres'
db.exec("DROP DATABASE IF EXISTS just_fkn_around;")
db.exec("CREATE DATABASE just_fkn_around;")
db = PG.connect dbname: 'just_fkn_around'

define_method(:sql) { |sql| db.exec(sql).to_a }

sql <<-SQL
-- some data to query

robsmith1776

CREATE EXTENSION tablefunc;

CREATE TABLE sales(year int, month int, qty int);
INSERT INTO sales VALUES(2007, 1, 1000);
INSERT INTO sales VALUES(2007, 2, 1500);
INSERT INTO sales VALUES(2007, 7, 500);
INSERT INTO sales VALUES(2007, 11, 1500);
INSERT INTO sales VALUES(2007, 12, 2000);
INSERT INTO sales VALUES(2008, 1, 1000);
INSERT INTO sales VALUES(2009, 5, 2500);

robsmith1776

Here's a few things I tried to write output to a python subprocess pipe.

from subprocess import Popen, PIPE

p = Popen('less', stdin=PIPE)
for x in xrange(100):
    p.communicate('Line number %d.\n' % x)

robsmith1776

# Needed PS packages
# Install-Package -Name pscx
# Install-Package -Name AWSPowerShell
#
# Scheduling
# The script then needs to be scheduled to run every night, I’m using scheduled tasks for this,
# creating a task that runs nightly and triggers the powershell script by running
# Powershell.exe with the arguments 
# -ExecutionPolicy Bypass C:\SqlBackup\SqlBackupToS3.ps1.
# From <https://www.rhysgodfrey.co.uk/b/blog/posts/backing-up-a-sql-database-to-amazon-s3-using-powershell>