edwinlab

-- show running queries (pre 9.2)
SELECT procpid, age(query_start, clock_timestamp()), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(query_start, clock_timestamp()), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

edwinlab

module ActiveRecord::UnionScope
  def self.included(base)
    base.send :extend, ClassMethods
  end
  
  module ClassMethods
    def union_scope(*scopes)
      id_column = "#{table_name}.#{primary_key}"
      sub_query = scopes.map { |s| s.select(id_column).to_sql }.join(" UNION ")
      where "#{id_column} IN (#{sub_query})"

edwinlab

package main

import (
	"fmt"
	"io"
	"os"
)

var path = "/Users/novalagung/Documents/temp/test.txt"

edwinlab

Working with time in Go is pretty straightforward.

Times

Get the current local time:

now := time.Now()                                   // 02 Apr 15 14:03

Construct a time with Date(y, m, d, h, m, s, ns, loc):

edwinlab

ISO - 25010 standard for product quality Quality Attributes in Software Architecture

edwinlab

The problem

In some cases, it is possible that PostgreSQL tables get corrupted. This can happen in case of hardware failures (e.g. hard disk drives with write-back cache enabled, RAID controllers with faulty/worn out battery backup, etc.), as clearly reported in this wiki page. Furthermore, it can happen in case of incorrect setup, as well.

One of the symptoms of such corruptions is the following message:

ERROR: missing chunk number 0 for toast value 123456 in pg_toast_45678

This almost surely indicates that a corrupted chunk is present within a table file. But there is a good way to get rid of it.

edwinlab

package main

import (
	"bytes"
	"crypto/aes"
	"crypto/cipher"
	"encoding/hex"
	"fmt"
)