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
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; |
timeSpent = 0; | |
timeStarts = 0 | |
browser.tabs.onActivated.addListener((activeInfo) => { | |
browser.tabs.sendMessage( | |
activeInfo.tabId, | |
{timeSpent: timeSpent} | |
).then(response => { | |
timeStarts = (new Date).getTime(); | |
}).catch(error => { |
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; }; |
... | |
inherit (import ../servers/sql/postgresql-default.nix pkgs super) | |
postgresql | |
postgresqlPackages | |
postgresql_9_4 | |
postgresql_9_5 | |
postgresql_9_6 | |
postgresql_10 | |
postgresql_11 |
#!/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 |
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
# First add this module to your /etc/nixos/configuration.nix | |
# ... | |
# imports = [ /path/to/iphone.nix ]; | |
# iphone.enable = true; | |
# iphone.user = "yourusername"; | |
# ... | |
# Then rebuild system. Attach iPhone via cable, open terminal and run command `iphone` | |
# It will fail, but there will occure a dialog on your iPhone to "trust this computer" | |
# Press OK there and run `iphone` again. If it succeeds it will open a freshly mounted folder |
Цей список складений з технологій (утиліт Linux), які я використаю для однієї життєвої ситуації - пошуку аренди квартири по риночній ціні.
Знайомим з поняттям "скрейпінг" мабуть уже зрозуміло, про що буде пост. Тим не менше, запрошую під кат.
OLX є, здається, найактивнішою площадкою для пошуку аренди квартири у Києві. Але просто зайти на OLX, задати фільтри (район, кількість кімнат) недостатньо. Справа в тім, що є 3 типи аренд:
with import <nixpkgs> { }; | |
runCommand "some-test" { | |
buildInputs = [ postgresql ]; | |
preCheck = '' | |
set -e | |
export PGDATA=$TMP/db | |
export PGHOST=$TMP/socketdir | |
mkdir $PGDATA $PGHOST | |
pg_ctl initdb | |
echo "unix_socket_directories = '$PGHOST'" >> $PGDATA/postgresql.conf |