I know that HiveServer doesnot support multi-client concurrency and authentication and is handled in HiveServer2.
I want to know how this is handled in HiveServer2 and why it doesnot support in HiveServer.
Thanks,
Sree
The answer for this question is simple, which I got to know few days ago.
Each and every client has to be connected through THRIFT API in hiveserver or hiveserver2 which in turn launches the process to convert the client code to hive understandable code by launching language specific class libraries.
As everyone is aware, a process can be single or multi threaded. In hiveserver1, the process launched is single threaded as the class libraries doesnot support multi threads. In hiveserver2, these have been upgraded to multi thread class libraries and thus supports multiple sessions.
Related to security, please refer the link below
http://blog.cloudera.com/blog/2013/07/how-hiveserver2-brings-security-and-concurrency-to-apache-hive/
Thanks,
Sree
Related
I have scyllaDB installed in cloud. I want to run queries and check the data. Is there any way to access it by any desktop UI client or does by default it provides any web UI to access it
Thanks
The typical interface with ScyllaDB is cqlsh which is command line. Documentation is at https://docs.scylladb.com/getting-started/cqlsh/
There are a few GUIs that claim to be front-ends for Cassandra. These should work for Scylla, but I've never used them.
I'm looking into Rhino Service Bus for a project instead of using commercial NServiceBus (which I know from my workplace).
In NServiceBus there's the concept of a distributor, which load balances tasks between server automatically to allow scale up. I searched and found a similar question about RSB, but with no example on how to actually implement it. RSB is a bit short in documentation (they have example projects on GitHub, but non with such example).
Does anyone know how to implement load balancing in RSB? or have any link to an article about it?
Thanks
I want to monitor JVM performance on my production environment. I have installed only JRE, not JDK, Hence i can't use jstat, jconsole etc. to monitor the JVM performance.
Can somebody please help to understand how can i monitor JVM performance in this scenario?
Is there any way to achieve this?
(please note that i don't want to monitor it remotely through JMX or something else. i would like to install local agent in each machine which will send the metrics to server at the interval of 1 minute.)
Thanks,
KS
If you manage to get JMX up and running on your VM (from the comment), you can then use jmxterm or jmxfetch to push these JMX metrics into a metrics system (like graphite or Datadog).
If you have enough patience and time to write, you can probably have a look at JVMTI. You can write your code in C/C++ and run it along your Java Process and you can gather information about the JVM without affecting it.
Another simple and naive way is to start your VM with a javaagent written in java but JVMTI is even better than that. The most crucial difference between the javaagent and JVMTI app is derived from the loading mechanics. While the agents are loaded inside the heap, they are governed by the same JVM. Whereas the JVMTI agents are not governed by the JVM rules and are thus not affected by the JVM internals such as the GC or runtime error handling.
You can even give Java Mission Control a try if you're using JDK7 or above :)
Jolokia is a java agent you can use to expose JMX as http. Run jmx2graphite and get those metrics into Graphite. The link includes instructions on Graphite installation (10 minutes)
I am looking for a tool capable of generating multiple Xmpp connections to load-test a XMPP server with a secure connection, especially starttls.
For a xmpp plain text authentication I had used jab_simul(followed this tutorial) and tsung both with success.
But I was unable to use the tolls above for the starttls,I peeked into the code of both tools and tried different configurations of the tools.
Another option I am pondering is using a xmpp library like eXmpp and make a specific load-testing tool myself with, instead of altering jab_simul (C software with comments in language i do not understand) or altering tsung(all purpose load-testing tool, so lots of place where you can go wrong).
short-story - I am looking for a tool or advice to stress-testing/load-testing a xmpp server.
We are facing exactly the same challenge right now. After deep consideration we found out that only especially build software can deliver the load we want to test. (Remember, you can configure ejabberd to something very specific :-)
For that we developed a small library called xmpp_talker https://github.com/burinov/xmpp_talker (Apache Licence) which is a kind of xmpp client made as a gen_server. I find it is a very nice starting point to build any kind of load simulation software. There is also echo_worker example included. So, you have good base to start. At the moment xmpp_talker is suited for exmpp 0.9.7. As far as I know in a few days will be out version 1.0.0. (or 0.9.9?) There are many bug fixes (trust me you don't want to know about them). On monday I will release xmpp_talker for exmpp 0.9.8 with proper service interruption handling.
In case you deside to go the same way xmpp_talker could be useful for you.
Added: Here is also great article that is realted to the topic: https://support.process-one.net/doc/display/EXMPP/Scalable+XMPP+bots+with+erlang+and+exmpp
There's also the recently started XMPP benchmarking project called xmppench which aims to be a high-performance benchmarking tool simulating some reasonable use cases of XMPP servers. It's written in C++, based on Swiften and boost.
I am working with an electronics appliance manufacturer to embed LAN based control systems into the products. The idea is to serve up a system configuration/control interface through a web browser so clients never need to install software. We can communicate with the appliance by sending and receiving serial data through the embedded module. Since the appliance can also be controlled from a front panel UI, it creates a challenge to keep a remote web interface in sync with very low latency. It seems like websockets or some sort of Push is what we need for handling real time events from the server to clients.
I am using a Lantronix Mathport AR embedded device server. Out of the box the unit will serve up any custom HTML and java servlets/applets. We have the option to install a lightweight Linux distro if we need more flexibility. I am not sure how to implement any server side apps since the device is not running standard Apache. I believe it is using Boa.
Can anyone guide me in the right direction of how to do this?
Some general info...The WebSocket protocol (draft spec here) is a simple layer on top of TCP. What this means is that, if you already have a TCP server for your platform, implementing the WebSocket is just a matter of hours. The protocol specifies a handshake and two ways of sending data frames.
I strongly suggest you start by reading the 39 pages spec.
As Tihauan already mentioned, start by reading the spec, and also note that there are still some changes ongoing, although websockets is now more stable than it was 1 year ago.
Key point for me was the requirement that websocket data is entirely UTF-8 text, which lends itself nicely to JSON based message definitions.
Our system uses a form of embedded linux, so we then added and made use of the following libraries:
"libwebsockets" from:
http://git.warmcat.com/cgi-bin/cgit/libwebsockets/
"jansson" from:
http://www.digip.org/jansson/
Using the above as support libraries, we created an internal lightweight "client/server" that allowed our other software modules to register for certain, applicable, websocket messages, and respond as needed. Worked great.
Good luck and best regards,
I'm a bit late, but Mozilla posted a guide entitled "Writing WebSocket servers", which literally guides you through writing a websocket server.
You will need to already know how HTTP works and have medium programming experience. Depending on language support, knowledge of TCP sockets may be required. The scope of this guide is to present the minimum knowledge you need to write a WebSocket server.
https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_servers