I guess you refer to this post?
http://1opensourcelover.wordpress.com/2013/07/02/solr-external-file-fields/
If so .. he already provides at least one possible use case:
*snip*
We use Solr to serve our company’s browse pages. Our browse pages are similar
to how a typical Stackoverflow tag page looks. That “browse” page has the
question title (which links to the actual page that contains the question,
comments and replies), view count, snippet of the question text, questioner’s
profile info, tags and time information. One thing that can change quite
frequently on such a page is the view count. I believe Stackoverflow uses Redis
to keep track of the view counts, but we have to currently manage this in Solr,
since Solr is our only datastore to serve these browse pages.
The problem before Solr 4.0 was that you could not update a single field in a
document. You have to form the entire document first (either by querying Solr
or using an alternate data source which contains all the info), update the view
count and then post the entire document to Solr. With Solr 4+, you can do
atomic update of a single field – the Solr server internally handles fetching
the entire document, updating the field and updating its index. But atomic
update comes with some caveats – you must store all your Solr fields (other
than copyFields), which can increase your storage space and enable updateLog,
which can slow down Solr start-up.
For this specific problem of updating a field more frequently than the rest of
the document, external file fields (EFFs) can come in quite handy. They have
one main restriction though – you cannot use them in your queries directly i.e.
they cannot be used in the q parameter directly. But we will see how we can
circumvent this problem at least partially using function query hacks.
*/snip*
another case, out of my head, might be product pricing or updates on stock
count.
- Stefan
On Thursday, December 5, 2013 at 11:11 PM, yriveiro wrote:
Hi,
I read this post http://1opensourcelover.wordpress.com/ about EEF's and I
found very interesting.
Can someone give me more use cases about the utility of EEF's?
/Yago
-
Best regards
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