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PostgreSQL is an open source database system.
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PostgreSQL rhaas.blogspot.com

Don't manually modify the Postgres data directory!

A general rule, but as with most things in software, there are exceptions:

Is Manual Modification of the Data Directory Ever Justified?

Sadly, I can’t answer “no” to this question. There are circumstances under which there is no reasonable alternative.

I’m definitely guilty of this and have mucked things up in the past (in dev, not prod!).

I still manually delete postmaster.pid a few times a month as Postgres doesn’t shut down completely sometimes when I reboot my computer. That file doesn’t get cleaned up, which results in Postgres not launching after the reboot.

PostgreSQL 2ndquadrant.com

Opinion: PostgreSQL is the world's best database

The title is not clickbait or hyperbole. I intend to prove that by virtue of both design and implementation that PostgreSQL is objectively and measurably a better database than anything currently available, with or without money considerations.

He goes on to detail 15(ish) reasons why Postgres stands out from the crowd. A compelling argument. I’d love to see similar write-ups by people who disagree.

CockroachDB openmymind.net

Migrating from Postgres to CockroachDB

This is a nice lessons learned post from one engineering team making a database switch.

Overall, I’m happy with how the effort turned out and with CockroachDB in general. Because it uses PostgreSQL’s wire protocol, existing PostgreSQL drivers should work as-is. But we did run into some challenges that are worth pointing out. Here’s a list of things you might want to consider…

I like the update at the end, which emphasizes the important of tests for making a switch of this magnitude:

The system that was migrated has solid tests and good coverage. While a lot of the differences we ran into are obvious (like lack of range types and triggers), others were more subtle (especially the odd on conflict behavior). Test coverage made a pretty significant impact in the speed of the migration and our confidence in pushing live.

PostgreSQL pg-structure.com

Extract the structure of a Postgres database into JavaScript

When your database is the source of truth, it’s often useful to inspect that truth and reuse it elsewhere in your application.

import pgStructure from "pg-structure";

async function demo() {
  const db = await pgStructure({ database: "db", user: "u", password: "pass" }, { includeSchemas: ["public"] });

  const table = db.get("contact");
  const columnNames = table.columns.map(c => c.name);
  const columnTypeName = table.columns.get("options").type.name;
  const indexColumnNames = table.indexes.get("ix_mail").columns;
  const relatedTables = table.hasManyTables;
}

PostgreSQL layerci.com

Postgres is a great pub/sub & job server

We all know Postgres is a great relational database (you do know that, don’t you?). When it comes time for a pub/sub solution, however, we often reach for Kafka, Redis, or RabbitMQ. But did you know that Postgres is pretty well suited as a persistent pub/sub server as well?

There are very few use cases where you’d need a dedicated pub/sub server like Kafka. Postgres can easily handle 10,000 insertions per second, and it can be tuned to even higher numbers. It’s rarely a mistake to start with Postgres and then switch out the most performance critical parts of your system when the time comes.

Check the linked article for how they use Postgres in this fashion and a nice list of other benefits. For my money, the fact that I’m not adding another moving part to my infrastructure is reason enough to start with Postgres and go from there.

Derek Sivers sivers.org

PostgreSQL self-contained stored procedures example

Based on Derek’s now page he has ended his 7 year sabbatical and he’s taking Seth Godin’s advice to publish something every day. What Derek shared here is part of that commitment…

This week, I wrote a shopping cart to sell my books directly from my own site. So I took a couple extra hours today to put my code into public view, so anyone can play around with it.

It’s a working self-contained shopping cart / store. It’s a very concrete example of using stored procedures to keep all the data logic together in one place. You can use it from JavaScript, Python, Ruby, or any language you want, since all the functionality is in the database itself. It works.

PostgreSQL github.com

A webdev platform built entirely in PostgreSQL

Aquameta is a web-based IDE for full-stack web development. Developers can manage HTML, CSS, Javascript, database schema, views, templates, routes, tests and documentation, and do version control, branching, pushing, pulling, user management and permissions, all from a single web-based IDE. In theory. And mostly in practice.

Under the hood, Aquameta is a “datafied” web stack, built entirely in PostgreSQL. The structure of a typical web framework is represented in Aquameta as big database schema with 6 postgreSQL schemas containing ~60 tables, ~50 views and ~90 stored procedures. Apps developed in Aquameta are represented entirely as relational data, and all development, at an atomic level, is some form of data manipulation. Also in theory. And mostly in practice.

This is super experimental, but what a cool idea. Eric Hanson’s been at it it off-and-on for 20 years now…

PostgreSQL blog.couchbase.com

Comparing Postgres JSONB with NoSQL

The Couchbase team did a great job putting together this fairly-reasoned analysis. It gives side-by-side comparisons of Postgres’ JSON query syntax and SQL++/N1QL, which is the query language used in Couchbase. It touches on indexes, performance, ergonomics, and finally where each is a good fit.

I’ve personally found that Postgres’ JSON data types provide just enough document-orientation that I can sprinkle in where it makes sense in our data models. But, as with all things in developer-land, YMMV!

Michael Malis YouTube

Writing an interpreter in SQL for fun and no profit!

Michael Malis at !!Con 2019:

Writing SQL can be hard. SQL code is a bizarre combination of yelling and relational algebra. How can we make writing SQL easier? By embedding our own programming language in our SQL queries of course! In this talk, we’ll take a look at how you use a combination of various Postgres features to build a programming language out of SQL.

PostgreSQL rob.conery.io

PostgreSQL tools for the visually inclined

jumping from SQL Server to PostgreSQL is much more than changing a tool. PostgreSQL was built on Unix, with Unix in mind as the platform of choice, and typically runs best when it’s sitting on some type of Unix box. The Unix world has a pretty specific idiom for how to go about things and it certainly isn’t visual!

Rob Conery with a deep dive into psql and what makes it awesome.

PostgreSQL tools for the visually inclined

Amazon Web Services enterprisedb.com

Is Amazon’s new MongoDB-compatible DBMS really PostgreSQL under the covers?

This is a nice rundown of the technical clues indicating that DocumentDB might be powered by Postgres.

PostgreSQL isn’t the only DBMS that scales writes vertically and reads horizontally via replication, but when you add this all up, especially some of the specific limitations, I think it makes a pretty compelling argument that PostgreSQL is the engine powering AWS DocumentDB.

Craig Kerstiens craigkerstiens.com

The best Postgres feature you're not using

Craig Kerstiens on why common table expressions (CTEs) are so cool:

For some reason most people throw out principles we follow in other languages such as commenting and composability just for SQL. … [CTEs] actually makes SQL both readable and composable, and even for my own queries capable of coming back to them months later and understanding them, where previously they would not be.

Click through for examples of these in use.

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