manniwood.com

This blog is updated more than the home page might imply, but only the most intersting stuff gets posted on the home page.

Multiline copy commands in psql!

13 Nov 2021

This explores a tip I saw on another blog about how to do multiline copy commands in psql.

Fun with tmux

2 Aug 2021

I finally got around to using tmux because I had a particular use-case where I figured it would shine. Details here.

Intro to assembler!

5 Jul 2021

I thought it would be a fun to try to write a very basic intro to assembler. I didn't get very far, but I figured my first few chapters might make a nice blog entry.

Reading PostgreSQL Files with Go

21 Dec 2020

I thought it would be a fun learning exercise to try to parse a PostgreSQL table file with Go. I definitely learned a lot. :-)

AWS and aws

13 Dec 2020

Everybody's using AWS these days. I've started keeping notes on the more intersting bits. In particular, the aws command-line utility is very handy for us command-line junkies.

Here's a look at extracting secrets into AWS Fargate containers from Systems Manager / Parameter Store.

Here's a look at using SQL to query parquet files in S3 from the command-line.

Args and Env Vars in Linux/amd64 Assembler

26 Apr 2020

Want to know where your Linux process's command-line args and env vars live on process starup? And how to get them from an assembler program?

Details here.

Counting 1-bits

25 Aug 2019

The book Hacker's Delight has a pretty neat way of counting the 1-bits in an integer. But my exploration shows that modern Intel CPUs have an instruction that do that for you, and that Go's math/bits library takes advantage of that instruction. Nonetheless, I leave notes that spell out the Hacker's Delight solution as obvoiusly as I can.

Details here.

Go Channels/Select

1 Aug 2018

I've been reading parts of Katherine Cox-Buday's Concurrency in Go, and I think this incomplete list of facts about channels and select statements is useful. A full table of channel operation/state/result is on page 75; these notes are just for me and whoever else may find them useful

Channels

Select Statements

PostgreSQL autovacuum tuning

20 Aug 2017

I have completely re-worked my writeup on tuning PostgreSQL for heavily-updated tables to take into account the usefulness of autovacuum_vacuum_cost_limit.