januszm

class Array
  def to_csv(csv_filename="hash.csv")
    require 'csv'
    CSV.open(csv_filename, "wb") do |csv|
      csv << first.keys # adds the attributes name on the first line
      self.each do |hash|
        csv << hash.values
      end
    end
  end

januszm

```ruby
record = Model.where("data->'$.somearray[0].email' = ?", email).first
```

januszm

SELECT
  TABLE_NAME AS `Table`,
  ROUND((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024) AS `Size (MB)`
FROM
  information_schema.TABLES
WHERE
  TABLE_SCHEMA = "mydatabase"
ORDER BY
  (DATA_LENGTH + INDEX_LENGTH)
DESC;

januszm

DROP extension postgis CASCADE;
/*
drop cascades to column shape of table MYTABLE_points
drop cascades to column shape of table MYTABLE_areas
*/

/* Upgrade PostgreSQL */

CREATE extension postgis;

januszm

SELECT 
    TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME, COLUMN_DEFAULT
FROM
    INFORMATION_SCHEMA.COLUMNS
WHERE
    TABLE_NAME='Xxx';

januszm

#!/bin/bash

# -d for no data, just structure
# -t for no create, just data
# --ignore-table=name1 --ignore-table=name2
# --skip-comments
# include table names after DATABASE
mysqldump -u USER -h HOST -p DATABASE | gzip > DATABASE.sql.gz

# load

januszm

rails_version = '6.1.3'
# Include rails specific gems
# We need this until https://github.com/rails/rails/issues/41750 is resolved
gem 'actioncable', rails_version
gem 'actionmailer', rails_version
gem 'actionpack', rails_version
gem 'actionview', rails_version
gem 'activejob', rails_version
gem 'activemodel', rails_version
gem 'activerecord', rails_version

januszm

# first, backup running config
docker exec -it -u 0 grafana bash
cat /etc/grafana/grafana.ini
# copy output and paste to backup file somewhere or use docker cp
docker cp grafana:/etc/grafana/grafana.ini grafana.ini.bak

docker pull grafana/grafana:latest
docker stop grafana
docker rm grafana
docker run --name grafana --detach=true --publish 80:3000 --link graphite:graphite --volumes-from grafana-storage grafana/grafana

januszm

# as root or with sudo

swapoff -a
sysctl -w vm.swappiness=1
sysctl -w fs.file-max=262144
sysctl -w vm.max_map_count=262144

yum install https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm
yum install mysql-devel redis-devel
amazon-linux-extras install redis4.0

januszm

# env - run a program in a modified environment
# envirotnment is read from crontab file, usually it's below and nothing else:
# SHELL=/bin/sh
# PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
env - `cat /etc/crontab | grep -v "#" | grep -v "^$" | grep -v /etc/cron` my_script.sh