vault13dweller

Tuning ZFS + Postgres to outperform EXT4 + Postgres

Please refer to ZFS 2-3x slower than EXT4 to see how ZFS defaults + Postgres defaults severely underperform EXT4 defaults + Postgres defaults (and also to know more about the system on which these benchmarks were performed). This page documents how to tune ZFS + Postgres to give better performance for the tpcb-like benchmark.

BIG FAT WARNING

Please do not copy these settings blindly because I am myself not clear on why/how these settings had the impact they did. For example, I cannot explain why full_page_writes=off independently did not give that much boost, nor did an optimized PG configuration. However, putting both of them together gave a 2-4x boost compared to baseline numbers.

Benchmark results

I've been working with Apache Kafka for over 7 years. I inevitably find myself doing the same set of activities while I'm developing or working with someone else's system. Here's a set of Kafka productivity hacks for doing a few things way faster than you're probably doing them now. 🔥

Show me all my Kafka topics and their partitions, replicas, and consumers
Show me the contents of a topic
Create a Kafka topic
Produce messages to a Kafka topic
Validate the schema of messages before producing to a topic
Do all of this at a distance

Get the tools

Rich Already Answered That!

A list of commonly asked questions, design decisions, reasons why Clojure is the way it is as they were answered directly by Rich (even when from many years ago, those answers are pretty much valid today!). Feel free to point friends and colleagues here next time they ask (again). Answers are pasted verbatim (I've made small adjustments for readibility, but never changed a sentence) from mailing lists, articles, chats.

How to use:

The link below in the summary jumps at the answer on this page.
The link on the question itself points back at the original post.

Summary

Squashing Git Commits

The easy and flexible way

This method avoids merge conflicts if you have periodically pulled master into your branch. It also gives you the opportunity to squash into more than 1 commit, or to re-arrange your code into completely different commits (e.g. if you ended up working on three different features but the commits were not consecutive).

Note: You cannot use this method if you intend to open a pull request to merge your feature branch. This method requires committing directly to master.

Switch to the master branch and make sure you are up to date:

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

Setup

git clone <repo>

clone the repository specified by ; this is similar to "checkout" in some other version control systems such as Subversion and CVS

Add colors to your ~/.gitconfig file:

	#!/usr/bin/env bash

	#! top-of-file comments can be written using more #! lines, which
	#! is a valid comment in both clojure and bash

	":";# alternately this works too

	#! The construction below uses cross-language syntactic hackery to
	#! specify the -Sdeps arg in a part of the file that's interpreted
	#! by clojure as clojure syntax (i.e., not a line comment), so it

	package org.keycloak.authentication.authenticators.browser;

	import org.keycloak.authentication.AuthenticationFlowContext;
	import org.keycloak.models.RoleModel;
	import org.keycloak.models.UserModel;

	import javax.ws.rs.core.MultivaluedMap;
	import java.util.List;
	import java.util.Map;
	import java.util.regex.Pattern;