Posts about NoSQL databases and Polyglot persistence from Monday, 9 August 2010
CouchDB 1.0: Critical Bug Found, Fix Available
Simply put, you may lose your data. Fortunately there’s a very detailed solution for it:
If you are using CouchDB 1.0.0 and have the default setting for ‘delayed_commits’ (true) then you are affected by this data loss bug.
[…]
For current users, these instructions will ensure your data is safe. First: do not restart your CouchDB!
The bug doesn’t affect previous CouchDB releases.
CouchDB 1.0: Critical Bug Found, Fix Available originally posted on the NoSQL blog: myNoSQL
NoSQL Databases Aren't Hierarchical
Unfortunately based on a wrong hypothesis:
However most of the NoSQL tools seem to be NoRelational. As I see it, many of these tools map closely to the model that the relational model replaced.. the hierarchical model. Some describe themselves as hierarchical.
While not sure what NoSQL databases the author is referring, from my point of view the common denominator of column stores, document databases and key-value stores is the key-value model which is not hierarchical. On the other hand, graph databases are using the graph model at their core which is again different from the hierarchical model. The Java Content Repository implementations (e.g. Jackrabbit) are the only systems I’m aware of being hierarchical, so the hypothesis doesn’t apply.
NoSQL Databases Aren’t Hierarchical originally posted on the NoSQL blog: myNoSQL
via: http://ramthemdown.wordpress.com/2010/08/07/a-historical-perspective-on-nosql/
Quick Guide for Riak with Clojure
From installation to using the Clojure library for Riak ☞ clj-riak including MapReduce with Riak:
This brief introduction leaves many aspects of Riak unaddressed. For example, we have not looked at throughput, scalability, fault tolerance, conflict resolution, or production operations – all critical to a complete understanding of the datastore.
Quick Guide for Riak with Clojure originally posted on the NoSQL blog: myNoSQL
sones GraphDB available on Microsoft Windows Azure
sones GraphDB available in the Microsoft cloud:
The sones GraphDB is the first graph database which is available on Microsoft Windows Azure. Since the sones GraphDB is written in C# and based upon Microsoft .NET it can run as an Azure Service in it’s natural environment. No Wrapping, no glue-code. It’s the performance and scalability a customer can get from a on-premise hosted solution paired with the elasticity of a cloud platform.
You can read a bit more about it ☞ here.
In case you’ve picked other graph database, you can probably set it up with one of the cloud providing Infrastructure-as-a-Service.
sones GraphDB available on Microsoft Windows Azure originally posted on the NoSQL blog: myNoSQL
Microsoft Azure and NoSQL Databases: MongoDB, sones GraphDB, and RavenDB
Looks like today is the day of the NoSQL databases in the Microsoft cloud. After covering how to run MongoDB on Azure and today’s guide to running sones GraphDB on Azure, the third one joining the party is RavenDB:
The short answer was, with the current build, no. RavenDB uses the .NET HttpListener class internally, and apparently that class will not work on worker roles, which are restricted to listening on TCP only.
[…]
I have to sign a contribution agreement, and do some more extensive testing, but I hope that Ayende is going to pull my TCP changes into the RavenDB trunk so that this deployment model is supported by the official releases.
So, two document stores and a graph database are already available for Microsoft Azure. Which one is next?
Microsoft Azure and NoSQL Databases: MongoDB, sones GraphDB, and RavenDB originally posted on the NoSQL blog: myNoSQL
via: http://blog.markrendle.net/2010/08/running-ravendb-on-azure.html
NoSQL Databases and Data Warehousing
I didn’t know data warehousing strictly imposes a relational model:
From a philosophical standpoint, my largest problem with NoSQL databases is that they don’t respect relational theory. In short, they aren’t meant to deal with sets of data, but lists. Relational algebra was created to deal with the large sets of data and have them interact. Reporting and analytics rely on that.
I’d bet people building and using Hive, Pig, Flume and other data warehousing tools would disagree with Eric Hewitt.
NoSQL Databases and Data Warehousing originally posted on the NoSQL blog: myNoSQL
CouchDB with a Riak Backend
Pure awesomeness:
To make CouchDB store documents remotely, we only have to replace the implementation of the two functions listed above. For our remote storage let’s use Riak as our Key-Value store (because it’s awesome). CouchDB persists Erlang terms to disk and Riak persists Erlang terms to disk. We get to remove redundant code from CouchDB since Riak is converting terms for us. Riak also automatically replicates everything we store, easily handles adding more machines to increase capacity, and deals with failures transparently.
Not only has Matt seen seen the connection between CouchDB and Riak, but he made it ☞ work.
CouchDB with a Riak Backend originally posted on the NoSQL blog: myNoSQL
via: http://matt.io/technobabble/The_Key-Value_Wars_of_the_Early_21st_Century/ui