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https://issues.apache.org/jira/browse/SOLR-8220?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15013633#comment-15013633
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Ishan Chattopadhyaya commented on SOLR-8220:
--------------------------------------------

{quote}
{noformat}
fl=myfield  // returns from either stored or docValues
fl=*_i         // returns all stored or docValues fields ending in _i
fl=*            // returns all stored fields and all docValues fields that are 
not stored
{noformat}
{quote}
This is a TODO. Also, need to add more tests around multivalued fields (here 
and in SOLR-8276).
As for LazyFields for non stored docvalues, I think it is an optimization that 
we can deal with later in a separate issue. Doing what we have in this patch 
itself is progress. If some committer can please take this forward, can we get 
this in for 5.4?
Keith, do you wish to tackle the above TODO (and other todo items)? If so, I 
will focus on SOLR-5944 for now.

> Read field from docValues for non stored fields
> -----------------------------------------------
>
>                 Key: SOLR-8220
>                 URL: https://issues.apache.org/jira/browse/SOLR-8220
>             Project: Solr
>          Issue Type: Improvement
>            Reporter: Keith Laban
>         Attachments: SOLR-8220-ishan.patch, SOLR-8220-ishan.patch, 
> SOLR-8220-ishan.patch, SOLR-8220-ishan.patch, SOLR-8220.patch, 
> SOLR-8220.patch, SOLR-8220.patch, SOLR-8220.patch, SOLR-8220.patch
>
>
> Many times a value will be both stored="true" and docValues="true" which 
> requires redundant data to be stored on disk. Since reading from docValues is 
> both efficient and a common practice (facets, analytics, streaming, etc), 
> reading values from docValues when a stored version of the field does not 
> exist would be a valuable disk usage optimization.
> The only caveat with this that I can see would be for multiValued fields as 
> they would always be returned sorted in the docValues approach. I believe 
> this is a fair compromise.
> I've done a rough implementation for this as a field transform, but I think 
> it should live closer to where stored fields are loaded in the 
> SolrIndexSearcher.
> Two open questions/observations:
> 1) There doesn't seem to be a standard way to read values for docValues, 
> facets, analytics, streaming, etc, all seem to be doing their own ways, 
> perhaps some of this logic should be centralized.
> 2) What will the API behavior be? (Below is my proposed implementation)
> Parameters for fl:
> - fl="docValueField"
>   -- return field from docValue if the field is not stored and in docValues, 
> if the field is stored return it from stored fields
> - fl="*"
>   -- return only stored fields
> - fl="+"
>    -- return stored fields and docValue fields
> 2a - would be easiest implementation and might be sufficient for a first 
> pass. 2b - is current behavior



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