Knock Engineering

All things Knock engineering & data science.

Jan 22, 2023

TIL — Postgres v15 features

All roles in Postgres inherit from the Public role and, therefore, can create objects on the public schema. This is no longer the case with Postgres v15.

It removes the default CREATE privilege, which is a good security measure. Now, we no longer have to…

Karan Sakhuja

Jan 18, 2023

TIL — Conditionally enable a Terraform module

We can conditionally enable or disable a Terraform module for different environments using the count meta-argument.

variable "ENABLE_DB" { 
  type = bool
  default = true 
}

module "database" {
  source =…

Karan Sakhuja

Jan 13, 2023

TIL — Postgres slow queries with pg_stat_statements

Using the pg_stat_statements extension, we can quickly identify problematic queries.

SELECT
  userid::regrole AS "user",
  "query",
  -- Number of times the query has been called
  calls AS "num_calls",
  -- Total…

Karan Sakhuja

Jan 11, 2023

TIL — Postgres RLS on VIEWs — part 2

This is a continuation of part 1

Karan Sakhuja

Jan 10, 2023

TIL — RLS on Postgres VIEWs

Views are useful for encapsulating commonly executed queries into a…

Karan Sakhuja

Jan 4, 2023

TIL — Postgres user-defined data types with DOMAINs

We can create a user-defined data type with constraints using DOMAIN. We will use citext here, so the email field is case-insensitive.

-- Install citext extension
CREATE EXTENSION IF NOT EXISTS "citext";

-- Create…

James Sumners

Jun 10, 2021

Knock and Open Source

Knock.com is built with Open Source Software (OSS). It permeates our technology stack from the interactive website all…