LISTSERV mailing list manager LISTSERV 16.5

Help for CODE4LIB Archives


CODE4LIB Archives

CODE4LIB Archives


CODE4LIB@LISTS.CLIR.ORG


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

CODE4LIB Home

CODE4LIB Home

CODE4LIB  March 2010

CODE4LIB March 2010

Subject:

Re: Q: XML2JSON converter

From:

"Houghton,Andrew" <[log in to unmask]>

Reply-To:

Code for Libraries <[log in to unmask]>

Date:

Fri, 5 Mar 2010 18:25:23 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (98 lines)

> From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of
> Bill Dueber
> Sent: Friday, March 05, 2010 05:22 PM
> To: [log in to unmask]
> Subject: Re: [CODE4LIB] Q: XML2JSON converter
> 
> This is my central point. I'm actually saying that JSON streaming is
> painful
> and rare enough that it should be avoided as a requirement for working
> with
> any new format.

OK, in principle we are in agreement here.

> I guess, in sum, I'm making the following assertions:
> 
> 1. Streaming APIs for JSON, where they exist, are a pain in the ass.
> And
> they don't exist everywhere. Without a JSON streaming parser, you have
> to
> pull the whole array of documents up into memory, which may be
> impossible.
> This is the crux of my argument -- if you disagree with it, then I
> would
> assume you disagree with the other points as well.

Agree with streaming APIs for JSON are a pain and not universal across all clients.

Agree that without a streaming API you are limited by memory constraints on the client. 

> 2. Many people -- and I don't think I'm exaggerating here, honestly --
> really don't like using MARC-XML but have to because of the length
> restrictions on MARC-binary. A useful alternative, based on dead-easy
> parsing and production, is very appealing.

Cannot address this concern.  MARC (ISO 2709) and MARC-XML are library community standards.  Doesn't matter whether I like them or not, or you like them or not.  This is what the library community has agreed to as a communications format between systems for interoperability.

> 2.5 Having to deal with a streaming API takes away the "dead-easy"
> part.

My assumption is that 2.5 is dealing with using a streaming API with MARC-XML.  I agree that using SAX in XML on MARC-XML is a pain, but that's an issue with dealing with large XML datasets, in general, and has nothing to do with MARC-21.  In general, when processing large MARC-XML I use SAX to get me a complete record and process at the record level, that isn't too bad, but I'll concede it's still a pain.  Usually, I break up large datasets into 10,000 record chunks and process them that way since most XML and XSLT tools cannot effectively deal with documents that are 100MB or larger, so I rarely ever use SAX anymore.

> 3. If you accept my assertions about streaming parsers, then dealing
> with
> the format you've proposed for large sets is either painful (with a
> streaming API) or impossible (where such an API doesn't exist) due to
> memory
> constraints.

Large datasets, period, are a pain to deal with.  I deal with them all day long and have to deal with tool issues, disk space, processing times, etc.
I don't disagree with you here in principle, but as I previously point out this is an API issue.

If your API never allows you to return a collection of more than 10 records which is less than 1MB, you are not dealing with large datasets.  If your API is returning a large collection of records that is 100MB or larger, then you got problems and need to rethink your API.

This is no different than a large MARC-XML collection.  The entire LC authority dataset, names and subjects, is 8GB of MARC-XML.  Do I process that as 8GB of MARC-XML, heck no!!  I break it up into smaller chunks and process the chunks.  This allows me to take those chunks and run parallel algorithms on them or throw the chunks at our cluster and get the results back quicker.

It's the size of the data that is the crux of your argument not the format of the data, e.g., XML, JSON, CSV, etc.

> 4. Streaming JSON writer APIs are also painful; everything that applies
> to
> reading applies to writing. Sans a streaming writer, trying to *write*
> a
> large JSON document also results in you having to have the whole thing
> in
> memory.

No disagreement here.
 
> 5. People are going to want to deal with this format, because of its
> benefits over marc21 (record length) and marc-xml (ease of processing),
> which means we're going to want to deal with big sets of data and/or
> dump batches of it to a file. Which brings us back to #1, the pain or
> absence of streaming apis.

So we are back to the general argument that large datasets, regardless of format, are a pain to deal with, and that tool sets have issues dealing with large datasets.  I don't disagree with these statements and run into these issues on a daily basis whether dealing with MARC datasets or other large datasets.  A solution to this issue is to create batches of stuff that can be processed in parallel, ever heard of Google and map-reduce :)

> "Write a better JSON parser/writer" or "use a different language" seem
> like
> bad solutions to me, especially when a (potentially) useful alternative
> exists.

OK, I will bite, you stated:

1. That large datasets are a problem.
2. That streaming APIs are a pain to deal with.
3. That tool sets have memory constraints.

So how do you propose to process large JSON datasets that:

1. Comply with the JSON specification.
2. Can be read by any JavaScript/JSON processor.
3. Do not require the use of streaming API.
4. Do not exceed the memory limitations of current JSON processors.

I'm open to any suggestions that comply with standards or work within a standard's extension framework. 


Andy.

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

March 2024
February 2024
January 2024
December 2023
November 2023
October 2023
September 2023
August 2023
July 2023
June 2023
May 2023
April 2023
March 2023
February 2023
January 2023
December 2022
November 2022
October 2022
September 2022
August 2022
July 2022
June 2022
May 2022
April 2022
March 2022
February 2022
January 2022
December 2021
November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003

ATOM RSS1 RSS2



LISTS.CLIR.ORG

CataList Email List Search Powered by the LISTSERV Email List Manager