When Postgres will not start
By Greg Sabino Mullane
November 24, 2014
One of the more frightening things you can run across as a DBA (whether using Postgres or a lesser system) is a crash followed by a complete failure of the database to start back up. Here’s a quick rundown of the steps one could take when this occurs.
The first step is to look at why it is not starting up by examining the logs. Check your normal Postgres logs, but also check the filename passed to the –log argument for pg_ctl, as Postgres may not have even gotten far enough to start normal logging. Most of the time these errors are not serious, are fairly self-explanatory, and can be cured easily—such as running out of disk space. When in doubt, search the web or ask in the #postgresql IRC channel and you will most likely find a solution.
Sometimes the error is more serious, or the solution is not so obvious. Consider this problem someone had in the #postgresql channel a while back:
LOG: database system was interrupted while in recovery at 2014-11-03 12:43:09 PST
HINT: This probably means that some data is corrupted and you will have to use the last backup for recovery.
LOG: database system was not properly shut down; automatic recovery in progress
LOG: …postgres
MongoDB and OpenStack — OSI Days 2014, India
By Selvakumar Arumugam
November 19, 2014
The 11th edition of Open Source India, 2014 was held at Bengaluru, India. The two day conference was filled with three parallel tech talks and workshops which was spread across various Open Source technologies.
In-depth look at Architecting and Building solutions using MongoDB
Aveekshith Bushan & Ranga Sarvabhouman from MongoDB started off the session with a comparison of the hardware cost involved with storage systems in earlier and recent days. In earlier days, the cost of storage hardware was very expensive, so the approach was to filter the data to reduce the size before storing into the database. So we were able to generate results from filtered data and we didn’t have option to process the source data. After the storage became cheap, we can now store the raw data and then we do all our filter/processing and then distribute it.
Earlier,
Filter -> Store -> Distribute
Present,
Store -> Filter -> Distribute
Here we are storing huge amount of data, so we need a processing system to handle and analyse the data in efficient manner. In current world, the data is growing like anything and 3Vs are phenomenal of growing (Big)Data. We need to handle the …
big-data cloud conference mongodb open-source
Brazilian Portuguese Liquid Galaxy website launch!
By Marco Manchego
November 17, 2014
End Point Corporation is pleased to announce the official launch of its new Brazilian Portuguese Liquid Galaxy website! The site, found at liquidgalaxy.pt.endpoint.com (now at visionport.com) officially signals the arrival of End Point’s Liquid Galaxy to Brazil, and aims to provide service to all current and future customers in what is South America’s largest and most dynamic market.
With a population over 200 million, Brazil is also a quick adopter of new technologies with sizeable industry sectors that can benefit directly from the implementation of a Liquid Galaxy. This includes a massive commodities sector, booming real estate, tourism and a vibrant media market, all of which are strong candidates for the technology.
Brazil is also a logical entry-point into the larger South American market in general. We’re confident that as we increase market penetration in Brazil, other opportunities in the region will soon follow. Dave Jenkins, our VP of Sales and Marketing, offers the following: “We’re excited to see this expansion into Brazil. I always see great things coming out of São Paulo and Rio whenever I go there for tech conferences, which are always booked to overflowing levels.” …
company visionport
Novo website do Liquid Galaxy em Português!
By Marco Manchego
November 17, 2014
End Point Corporation tem o prazer de anunciar o lançamento oficial do seu novo website em Português! O site, liquidgalaxy.pt.endpoint.com (visionport.com) oficialmente sinaliza a chegada do Liquid Galaxy da End Point ao Brasil e tem como objetivo fornecer serviço a todos os atuais e futuros clientes em um dos maiores e mais dinâmicos mercados da América do Sul.
Com uma população de mais 200 milhões, o Brasil também é um rápido adoptante de novas tecnologias com um numero considerável de líderes do setor que podem beneficiar diretamente a implementação do Liquid Galaxy. Isto inclui um setor de commodities solido, uma expansão imobiliária cresente, turismo e um mercado de mídia vibrante, todos fortes candidatos para a nova tecnologia.
Brasil também é o ponto de entrada para o mercado sul-americano em geral. Estamos confiantes de que podemos aumentar a penetração no mercado Brasileiro, outras oportunidades na região irão seguir. Dave Jenkins, nosso vice-presidente de vendas e Marketing, oferece o seguinte: “nós estamos excitados para ver essa expansão no Brasil. Eu sempre vejo grandes coisas saindo de São Paulo e Rio, sempre participo das conferências tecnologicas, que estão …
company visionport
Create a sales functionality within Spree 2.3 using Spree fancy
By Bianca Rodrigues
November 14, 2014
Introduction
I recently started working with Spree and wanted to learn how to implement some basic features. I focused on one of the most common needs of any e-commerce business—adding a sale functionality to products. To get a basic understanding of what was involved, I headed straight to the Spree Developer Guides. As I was going through the directions, I realized it was intended for the older Spree version 2.1. This led to me running into a few issues as I went through it using Spree’s latest version 2.3.4. I wanted to share with you what I learned, and some tips to avoid the same mistakes I made.
Set-up
I’ll assume you have the prerequisites it lists including Rails, Bundler, ImageMagick and the Spree gem. These are the versions I’m running on my Mac OS X:
- Ruby: 2.1.2p95
- Rails: 4.1.4
- Bundler: 1.5.3
- ImageMagick: 6.8.9-1
- Spree: 2.3.4
What is Bundler? Bundler provides a consistent environment for Ruby projects by tracking and installing the exact gems and versions that are needed. You can read more about the benefits of using Bundler on their website. If you’re new to Ruby on Rails and/or Spree, you’ll quickly realize how useful Bundler is when updating your gems.
After …
ecommerce rails spree
Can we Server Name Indicate yet?
By Josh Williams
November 13, 2014
The encryption times, they are a-changin’.
Every once in a while I’ll take a look at the state of SNI, in the hopes that we’re finally ready for putting it to wide-scale use.
It started a few years back when IPv6 got a lot of attention, though in reality very few end user ISPs had IPv6 connectivity at that time. (And very few still do! But that’s another angry blog.) So, essentially, IPv4 was still the only option, and thus SNI was still important.
Then earlier this year when Microsoft dropped [public] support for Windows XP. Normally this is one of those things that would be pretty far off my radar, but Internet Explorer on XP is one of the few clients* that doesn’t support SNI. So at that time, with hope in my heart, I ran a search through the logs on a few of our more active servers, only to find that roughly 5% of the hits are MSIE on Windows XP. So much for that.
(* Android < 3.0 has the same problem, incidentally. But it in contrast constituted 0.2% of the hits. So I’m not as worried about the lack of support in that case.)
Now in fairly quick succession a couple other things have happened: SSLv3 is out, and SSL certificates with SHA-1 signatures are out. This has me …
tls sysadmin security
Dear PostgreSQL: Where are my logs?
By Josh Tolley
November 12, 2014
When debugging a problem, it’s always frustrating to get sidetracked hunting down the relevant logs. PostgreSQL users can select any of several different ways to handle database logs, or even choose a combination. But especially for new users, or those getting used to an unfamiliar system, just finding the logs can be difficult. To ease that pain, here’s a key to help dig up the correct logs.
Where are log entries sent?
First, connect to PostgreSQL with psql, pgadmin, or some other client that lets you run SQL queries, and run this:
foo=# show log_destination ;
log_destination
-----------------
stderr
(1 row)
The log_destination setting tells PostgreSQL where log entries should go. In most cases it will be one of four values, though it can also be a comma-separated list of any of those four values. We’ll discuss each in turn.
Syslog
Syslog is a complex beast, and if your logs are going here, you’ll want more than this blog post to help you. Different systems have different syslog daemons, those daemons have different capabilities and require different configurations, and we simply can’t cover them all here. Your syslog may be configured to send …
postgres logging
Finding specific Git commit at a point in time
By Greg Sabino Mullane
November 10, 2014
When using Git, being able to track down a particular version of a file is an important debugging skill. The common use case for this is when someone is reporting a bug in your project, but they do not know the exact version they are using. While normal software versioning resolves this, bug reports often come in from people using the HEAD of a project, and thus the software version number does not help. Finding the exact set of files the user has is key to being able to duplicate the bug, understand it, and then fix it.
How you get to the correct set of files (which means finding the proper Git commit) depends on what information you can tease out of the user. There are three classes of clues I have come across, each of which is solved a different way. You may be given clues about:
- Date: The date they downloaded the files (e.g. last time they ran a git pull)
- File: A specific file’s size, checksum, or even contents.
- Error: An error message that helps guide to the right version (especially by giving a line number)
Finding a Git commit by date
This is the easiest one to solve. If all you need is to see how the repository looked around a certain point in …
git