zerothabhishek

DELIMITER $$
CREATE FUNCTION `haversine` (lat1 DECIMAL(8,6), lng1 DECIMAL(8,6), lat2 DECIMAL(8,6), lng2 DECIMAL(8,6)) RETURNS DECIMAL(8,6)
BEGIN
    DECLARE R INT;
    DECLARE dLat DECIMAL(30,15);
    DECLARE dLng DECIMAL(30,15);
    DECLARE a1 DECIMAL(30,15);
    DECLARE a2 DECIMAL(30,15);
    DECLARE a DECIMAL(30,15);
    DECLARE c DECIMAL(30,15);

zerothabhishek

  class FacilitiesServicesForm

    include ActiveModel::Validations
    include ActiveModel::Conversion
    extend ActiveModel::Naming

    # These are sort of like the has_many relation
    attr_accessor :facilities_offerred,
                  :services_offerred
    

zerothabhishek

Memcache

Server: Ubuntu 16.04.1
Client: Ubuntu 16.04.1, Ruby 2.3 client (Dalli)
Memcache version: 1.4.25
Config changes:

• Changed bind setting to allow external connections

Client code:

zerothabhishek

#
# We have something called a PartialCalculator in the code
# for calculating some health related parameters.
#
# The PartialCalculator works like this -
#
#  - take an input hash
#  - merge the given data with some standard values
#  - calls a FullCalculator with the values (in the overall method)
#

zerothabhishek

The workshop shall be a series of lectures and coding sessions (mentioned as Practical here)

Session-1: Basics

• Lecture:
  • variables
  • Branching
  • puts, p
  • Define a method
• IRB

zerothabhishek

# lib/tasks/db.rake
namespace :db do

  desc "Dumps the database to db/APP_NAME.dump"
  task :dump => :environment do
    cmd = nil
    with_config do |app, host, db, user|
      cmd = "pg_dump --host #{host} --username #{user} --verbose --clean --no-owner --no-acl --format=c #{db} > #{Rails.root}/db/#{app}.dump"
    end
    puts cmd

zerothabhishek

A Git process

• Developer creates a new branch for every bug-fix or feature
• Feature branch is always created from master
• Developer watches master branch for changes. If another team member updates the master, she updates feature branch too.
• Feature branches are updated using rebase, not by merging
• Developer deploys the feature branch for demo/QA
• Another team member reviews code in the feature branch
• After demo and review passes, developer squash-merges the feature branch in her master, and pushes to the origin master
• For production-deployment, developer sets a tag on the origin/master, and deploys using the tag

zerothabhishek

The November 2015 meetup was held at the Postmark office on 21st. Here are some pictures.

The meet-up began with an introductory talk about the host company by Mithin. After that we went into the first talk, Speed up Mongo, by Gaurav Shah. The talk was about various lessons learned about Mongo performance in production. The talk also spawned many minor discussions via which we went into some other nitty-gritties of Mongo-Db. The slides are worth a look if you are planning to use Mongo for a project, and are curious about scaling.

The second talk was on Fraud Detection and Prevention in Ecommerce by Ketan Jain. This talk was about the many techniques that Postmark and similar companies apply to check fraud. An interesting and relatable talk, as many scenarios discussed are applicable in In

zerothabhishek

EXPLAIN
  SELECT posts.*, comments.*
   FROM posts LEFT JOIN comments
   ON posts.id = comments.post_id;

# Before adding indexes

                               QUERY PLAN
------------------------------------------------------------------------
 Hash Right Join  (cost=394.50..2589.00 rows=50000 width=150)

zerothabhishek

SELECT posts.*, comments.*
FROM posts LEFT JOIN comments
ON posts.id = comments.post_id;