[SOLR-8001] Using value sources on a multi-valued field can result in an exception if no data

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 5.3
• Fix Version/s: 5.4
• Assignee: Chris M. Hostetter
• Reporter: David Smiley
• Created: 01/Sep/15 20:31
• Updated: 15/Dec/15 13:55
• Resolved: 03/Sep/15 18:13

Description

SOLR-2522 Introduced the ability to reference a multi-valued field with doc values in a function query (value source) such as like this (an example using it for sorting): sort=field(myMultiValField,min) asc. In the event that the document has no values for this field, this feature behaves nicely in the aforementioned example. And it does if you reference in a 'fl' (as a DocTransformer): fl=id,myMultiValField:field(myMultiValField,min). In that case, the returned document simply doesn't have a name-value pair. But, if you sort on a more complex function that incorporates this, then you get an ArrayIndexOutOfBoundsException. Such as this:
sort=sum(otherField,field(myMultiValField,min)) asc There may be other conditions where this same exception will be thrown; not sure.

The root cause can either be considered one of two things (or both) I think:

• The longVal, intVal, etc. methods on FunctionValues need to be prepared for the possibility that the document has no data, in which case it should return a default value. This means TrieLongField (& friends) are erroneous.
• ValueSource.ValueSourceComparator could/should call exists before calling doubleVal in the various methods where it does.

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A workarround for Solr 5.3 users that should work in any situation is to wrap the field function in a def function since that forces an existence check before attempting to access the value (ie: use sort=def(field(mult_field,min),0)+asc instead of sort=field(mult_field,min)+asc)

Issue Links

• is related to: SOLR-8005 when some docs have no values, sorting on field(multivalued_field,min/max) has inconsistent ordering compared to sorting on same effective values in a single valued field
• is related to: SOLR-2522 add syntax for selecting the min or max of a multivalued field in value source functions