Ya, I like this idea.
Adding a "meta" field is OK, but it may just be kicking the can. Also
implementation wise, it works well when you have a SolrDocument, but
when directly using DocList, it gets a bit messy.
https://issues.apache.org/jira/browse/SOLR-705
Also with adding a "meta" field, I'm not sure I like that it is a
double object like:
doc.get( "_meta_" ).get( "distance")
It would be nicer if the user does not have any idea if it is a pseudo-
field or "real" field. (by "user" I mean how you consume the
response, not how you construct the URL)
The SQL "as" command comes to mind:
SELECT name, count(xxx) as cnt
ryan
On Aug 17, 2009, at 6:00 PM, Grant Ingersoll wrote:
I'm looking a little bit at https://issues.apache.org/jira/browse/SOLR-1298
and some of the other "pseudo-field" capabilities and am curious
how the various Response Writers are handling writing out the Docs.
The XMLWriter seems to have a very different approach from the
others when it comes to dealing with multi-valued fields (it sorts
first, the others don't.) Does anyone know the history here?
Also, I'm thinking about having a real simple interface that would
allow for, when materializing the Fields, to pass in something like
a DocumentModifier, which would basically get the document right
before it is to be returned (possibly inside the SolrIndexReader,
but maybe this even belongs at the Lucene level similar to the
FieldSelector, although it is likely too late for 2.9.) Through
this DocModifier, one could easily add fields, etc.
Part of what I think needs to be addressed here is that currently,
in order to add fields, for instance, LocalSolr does this, one needs
to iterate over the DocList (or SolrDocList) multiple times.
SolrPluginUtils.docListtoSolrDocList attempts to help, but it still
requires a double loop. The tricky part here is that one often
needs to have context when modifying the Document that the Response
Writer's simply do not have, so you end up writing a SearchComponent
to do it and thus iterating multiple times.
I know this is a bit stream of conscience, but thought I would get
it out there a little bit to see what others thought.
-Grant
