-CHAN (Comprehensive Hive Archive Network) (Was Re: Using Reflect: A thread for ideas)
Robin Morris 2013-02-14, 06:59
I think we need to think a little bigger than this.
Recently I've been thinking that what would be most useful to the Hive user community would be a CHAN – Comprehensive Hive Archive Network, (analogous to CPAN, CRAN, CTAN etc.). A central place where user-contributed UD[A,T]Fs could be uploaded and made available to the wider community.
Is there interest in the user community for something like this?
From: John Omernik <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
Reply-To: "[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>" <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
Date: Wednesday, February 13, 2013 8:38 PM
To: "[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>" <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
Subject: Using Reflect: A thread for ideas
I stumbled across the little documented reflect function today. I've always known about it, but java scares me if it's not in a cup so I didn't dig. Well today I dug, and found an awesome use case for reflect (for me) and wanted to share. I also thought it would be nice to validate some thoughts I had on reflect, and how we could possibly share ideas on reflect so that folks could get more use out of this great feature of hive.
Here's my example: A simple URL decode function:
select url, reflect('java.net.URLDecoder', 'decode', url, 'utf-8') as decoded_url from logs
Basically I am using the decode function of the java.net.URLDecoder class. Pretty awesome, works great, no files to distribute either. Even works through JDBC!
Ok that being said, I realized now that the function I am trying to call has to return data in a simple data type. For example, I struggle to come up with a simple reflect() for making an Hex MD5 out of a string because the built in function return an object, which have methods that can return what I am looking for. Which is great, but then I have to compile java code, distribute a jar, and then run the code. I am looking for simple like the URLDecoding function.
I love this reflect feature, but I think it's probably underutilized due to the perceived usability issues for beginners. So that leads me to my next thought. What if we brain storm here handy functions in Java that are not included in the standard hive language, that make the transition to hive well using the reflect function and the show an example of it's use? I went first with my URLDecode, and obviously will be looking for more, but have you seen some examples that we neat and worked well for you? Can you share?
Perhaps if we get enough examples we could roll some of these into a wiki page on the hive wiki that folks can use to get over the "perceived" complexity of using java reflect?
Thanks to those who have worked hard to implement features like this, it is truly awesome.
Connell, Chuck 2013-02-14, 13:58
Patrick D'Souza 2013-02-14, 16:30
John Omernik 2013-02-14, 12:45