问题
I am trying to develop application using Hive as the Database, and then I also find noSQL solutions as an alternative to it.
Now decided to develop using Cassandra, my next problem is about what client should I use? which one is better, Hector -- a pure java solutions, or Kundera with JPA like development?
I prefer Hector, but I am curious about Kundera. Is there anyone using Kundera? Which is better?
I'm curious about CQL (Cassandra Query Language). Can it integrate with Hector?
回答1:
Hector is slowly moving towards CQL integration. The first steps have been made, but because of the experience of an unstable API, the developers seem to have postponed a new release. The CQL API is rather new, as it should be nearly equivalent to a SQL syntax. I made some basic steps with CRUD operations to verify that data could be written and read via CQL.
Nevertheless, the CQL JAR is not usable out of the box like a standard JDBC driver as of now, and misses some important feature aspects. Having a look at the more or less difficult to understand thrift API and the not really much simpler hector API, I am convinced that CQL will be established as the state-of-the-art access API for Cassandra in version 0.8.1 and 1.0, where thrift will remain the native, raw access for some time.
The competition between both APIs has nothing to do with the decision of Hector. Hector itself provides additional services like failure and connection handling in the cluster. These are features being addressed by neither thrift nor CQL.
I don't really believe in all other O/R mappers, or even those claiming to provide a full-fledged JPA. I cannot imagine how this should work.
回答2:
Answering your question about clients - Hector essentially provides access to the Cassandra native API (columns, column families, rows etc) whereas Kundera aims to hide these details and provide object-database mapping.
Kundera therefore probably makes it easier to quickly persist a range of Java objects into Cassandra - but may not provide an efficient mapping, perhaps losing some of the performance that noSQL approaches provide.
Hector expects you to adapt to the Cassandra data model - this will be harder work, but is likely to deliver more performance.
回答3:
There is now a new client, Astyanax, released by Netflix in January 2012.
"Astyanax is a Java Cassandra client. It borrows many concepts from Hector but diverges in the connection pool implementation as well as the client API. One of the main design considerations was to provide a clean abstraction between the connection pool and Cassandra API so that each may be customized and improved separately. Astyanax provides a fluent style API which guides the caller to narrow the query from key to column as well as providing queries for more complex use cases that we have encountered. The operational benefits of Astyanax over Hector include lower latency, reduced latency variance, and better error handling."
The source code for Astyanax is hosted at Github: https://github.com/Netflix/astyanax
回答4:
For details about using CQL with Cassandra and Hector, see: https://github.com/rantav/hector/wiki/Using-CQL
The following mail list thread is a good discussion on where we will be going with CQL as an API: http://groups.google.com/group/hector-users/browse_thread/thread/540dc9c3908fbb44/f5ee488f2178e2f4
回答5:
For the sake of completeness I think the Pelops library should be mentioned too. Hector seems to be the most used, but Pelops has a simpler API. Pelops does not support CQL.
Coming from Ruby I find both to be extremely verbose and imperative, though.
回答6:
Kundera no more relies on Solandra for indexing approach. It enables you now to use secondary indexing support provided by Cassandra and as well as it gives you a way to run jpa queries over OPP (like range queries etc). We are working to enable native CQL support.
Take a look at: http://mevivs.wordpress.com/2012/02/13/how-to-crud-and-jpa-association-handling-using-kundera/
for more details.
-Vivek
回答7:
There is no java client in the same level with hector, hector is the best and there is work in progress in hector side to support cql. I saw cql commits for hector in github this month, but doesn't know it's final state. You can ask it to hector users group http://groups.google.com/group/hector-users
Also there is a very simple object mapper in hector https://github.com/rantav/hector/wiki/Hector-Object-Mapper-%28HOM%29
My Best,
Serdar Irmak
回答8:
Kundera 2.0.4 released:
Major Changes in this release:
- Cross-datastore persistence( Easy to migerate existing mysql app over nosql)
- support for relational databases (e.g Mysql etc)
- replace solandra with lucene based indexing.
- Support added for bi-directinal associations.
- Performance improvement fixes.
We tested and 1 million inserts with proper indexing happened in 6 minutes.
Vivek
回答9:
I am yet to try Hector, but am involved in latest Kundera 2.0.1 release. I suggest you give it a try. It has gone a major change since its inception and you can see a lot of new features getting added and bugs being fixed. Currently it supports JPA 1.0 and Cassandra 0.7.6 but we are planning to add support for Cassandra 0.8 and JPA 2.0 very soon. There is a pretty good example here: https://github.com/impetus-opensource/Kundera/wiki/Getting-started that may help you get started.
回答10:
Astyanax api produces human-readable code and does include connection pooling.
回答11:
CQL support over cassandra has been integrated in kundera 2.0.6(yet to be released). It allows to execute CQL as nativequery now.
-Vivek
来源：https://stackoverflow.com/questions/6151078/about-java-cassandra-client-which-one-is-better-how-about-cql