danbst

Pure Nix Minecraft launchers

1. Download .nix file

2. Run:

   $ nix run -f all-minecrafts.nix versions.v1_8_9.client -c minecraft

3. Enjoy (…​power of fixed-output derivations)!

danbst

Hey let’s start a list:

1. Yeah, all good.

   a bit of code.
   Oh wow, it is indented compared to markdown!

   A bit of text. Wow, it is indeted as well!

danbst

I use separate Firefox profiles for work and personal stuff. To distinguish those I place them on different workspaces.

• Workspace 0: firefox --no-remote -P MyJob
• Workspace 1: firefox --no-remote -P default

I have also company Slack on Workspace 0. Which usually contains links to some work stuff.

The problem

danbst

create extension "uuid-ossp";
-- https://www.postgresql.org/docs/current/bloom.html
create extension bloom;

CREATE or replace FUNCTION hashuuid(u uuid) RETURNS integer AS $$
DECLARE
   a bytea := uuid_send(u);
BEGIN
   RETURN (get_byte(a, 3) << 24) + (get_byte(a, 2) << 16) + (get_byte(a, 1) << 8) + get_byte(a, 0);
END;

danbst

timeSpent = 0;
timeStarts = 0

browser.tabs.onActivated.addListener((activeInfo) => {
    browser.tabs.sendMessage(
        activeInfo.tabId,
        {timeSpent: timeSpent}
    ).then(response => {
        timeStarts = (new Date).getTime();
    }).catch(error => {

danbst

let
  sub = { config, lib, parentConfig, ...}: {
      options.foo = lib.mkOption {
          type = lib.types.bool;
          default = parentConfig.bar;
      };
  };

in { config, lib, ...}: {
    options.bar = lib.mkOption { type = lib.types.bool; default = true; };

danbst

...

 inherit (import ../servers/sql/postgresql-default.nix pkgs super)
    postgresql
    postgresqlPackages
    postgresql_9_4
    postgresql_9_5
    postgresql_9_6
    postgresql_10
    postgresql_11

danbst

nixos executable

Basic features:

• installable as package, even on non-nixos
• is named nixos
• is written in C++ and binds to Nix C++ library (or maybe Haskell? Nodejs? What you think?)
• autocomplete, ncurses, Nix 2.0
• commit to Git by default on each rebuild

Subcommands

danbst

#!/usr/bin/env bash
statefile=~/.config/nixpkgs/declarative

action="$1"
package="$2"

mkdir -p $(dirname "$statefile")
touch "$statefile"
function update {
  envExpr=~/.config/nixpkgs/declarative-env.nix

danbst

VACUUM FREEZE

Our database has fast rate of transactions. I did think, that such rate is impossible, until I've seen it with my eyes. I've been instinctively insisting on fixing code to reduce number of transactions (sometimes successful), but never checked what are consequences for database.

One of consequences is fast rate of autovacuum VACUUM FREEZE.

VACUUM is essential for Postgresql to mark non-visible rows (those which were normal rows, but became invisible because of update or delete) as visible to PG. Note, that they become visible only to PG, previously PG didn't know they are free for use, and thus had allocated extra buffers in the end of a table for any new rows (inserts or updates). PG not knowing which rows are free for use is another problem, which causes table bloat, which deserves another post.

VACUUM FREEZE is special kind of VACUUM. From resource usage perspective, it differs from VACUUM by that it has to scan full table (normal VACUUM processes only buffers known to contain at