Sodeso

Apache Cassandra version 0.6.3 has been released and this release contains some very nice fixes. The download can be found at the following location:

http://cassandra.apache.org/download/

The following is a complete listing of all the changes in this release (i have added URL’s to the Jira issues so you can easily look them up for details):

• retry to make streaming connections up to 8 times. (CASSANDRA-1019)
• reject describe_ring() calls on invalid keyspaces (CASSANDRA-1111)
• fix cache size calculation for size of 100% (CASSANDRA-1129)
• fix cache capacity only being recalculated once (CASSANDRA-1129)
• remove hourly scan of all hints on the off chance that the gossiper missed a status change; instead, expose deliverHintsToEndpoint to

… Read more >

Importing and exporting data from a database is something important, it keeps you save when hardware / software fails and adds the ability to perform common database administration tasks. If something goes wrong you can just recover an earlier made backup.

Cassandra support two different ways of backing up data. The first way is by using the nodetool in combination with the snapshot argument, this creates a complete dump of the data. Before you start using the snapshot tool to create a backup read the documentation online, there are some playing rules involved.

However, in this topic i will discuss the second method. Cassandra provides two applications for exporting and importing data, sstable2json and json2sstable. Like the name suggests, an export is stored in a JSON style formatting, if you want to know more about the JSON data structures i suggest you head over to the following website:

http://www.json.org/… Read more >

In part three of Installing and using Apache Cassandra With Java we already talked about sorting and the various sorting types that are available by default. this time we are going to have a look as to what is needed to create your very own sorting type. In this example we will create a sorting type which will sort the data as if they are dates. Now to clarify already, i use the european notation style (dd-MM-yyyy) so don’t get confused by that.

Also what is very important to know, the sorting types are used when you are storing data (i mentioned this in part three), however, the sorting types are also used when you are using the get_slice method of the Cassandra Client.

As i mentioned in part three Cassandra provides us with an abstract class org.apache.cassandra.db.marshal.AbstractType which we must extend to define our sorting behavior. When… Read more >

Lets continue where we left off with part four, last time we handled the storing, mutating, deleting and searching of data for a standard ColumnFamily. This time we will do the same but then we are going to look at how it is done for the SuperColumnFamily. We will also have a look at how to create a sort of index. Last time we handled everything for an Author, this time… Read more >