Hoss Man created SOLR-6575:
------------------------------
Summary: ValueSources/FunctionValues should be able to
(dynamically) indicate their prefered data type (propogating up)
Key: SOLR-6575
URL: https://issues.apache.org/jira/browse/SOLR-6575
Project: Solr
Issue Type: Improvement
Reporter: Hoss Man
Something i've been thinking about for a while, but SOLR-6562 recently goaded
me into opening a jira for...
The ValueSource/FunctionValues API is designed to work with different levels of
math precision (int, long, float, double, date, etc...) and the
FunctionValues.objectVal() method provides a generic way to fetch an arbitrary
type from any FunctionValues instance -- which can be in the "preferred" type
for a given ValueSource can be retrieved (ie: an "Integer" if the ValueSource
corrisponds to the DocValues of an int field).
But for ValueSources thta wrap other value sources (ie: implementing math
functions like "sum" or "product" there is no easy way at runtime to know which
of the underlying methods on the FunctionValues is the "best" one to call. It
would be helpful if FunctionValues or ValueSource had some type of method on it
(ie: "canonicalDataType()" that could return some enumeration value inidacting
which of the low level various methods (intValue(docid), floatValue(docid),
etc...) were best suited for the data it represents.
Straw man idea...
For the lowest level ValueTypes coming from DocValues, these methods could
return a constant -- but for things like "SumValueSource" "canonicalDataType()"
could be recursive -- returning the least common denominator of the
ValueSources it wraps. the corrisponding intValue() and floatValue() methods in
that class could then cast appopriately.
So even if you have SumValueSource wrapped arround several IntDocValuesSource,
SumValueSource.canonicalDataType() would return "INT" and if you called
SumValueSource's FunctionValues.intValue(docid) it would add up the results of
the intValues() methods on all of the wrapped FunctionValues -- but
floatValues(docid) would/could still add up the results of the
floatValue(docid) results from all of the wrapped FunctionValues (for people
who want to coerce float based math -- ie: SOLR-6574)
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
