Hi Erick,
please consider this case where there is a group products that are
televisions.
Now I have only one category per product, but in same cases like the
television I could have more than one.
Some products should be available simultaneously in more categories, thats
why the field I was trying to group is a multivalue, for example:
/home-video/televisions/tv-led (516)
/home-video/televisions/tv-ultra-hd-4k (363)
/home-video/televisions/smart-tv (19)
So there can be a television that is simultaneously a TV led, a smart tv
and is ultra hd 4k.
So, for example, I should be able to submit the following query:
- fq=available:true
- fq=vertical:0
- q=television
- rows=3
- group=true
- group.field=category
- group.limit=0
So the returned groups should be something like this (this is the output I
have now for the single value field)
<lst name="grouped">
<lst name="category">
<int name="matches">51653</int>
<arr name="groups">
<lst>
<str name="groupValue">/home-video/televisions/tv-led</str>
<result name="doclist" numFound="516" start="0"
maxScore="0.6224861">
</result>
</lst>
<lst>
<str name="groupValue">/home-video/televisions/tv-ultra-hd-4k</str>
<result name="doclist" numFound="363" start="0"
maxScore="0.5923965">
</result>
</lst>
<lst>
<str name="groupValue">/home-video/televisions/smart-tv</str>
<result name="doclist" numFound="19" start="0" maxScore="0.5749302">
</result>
</lst>
</arr>
</lst>
</lst>
On Mon, Feb 26, 2018 at 4:44 PM, Erick Erickson <erickerick...@gmail.com>
wrote:
> What does "group by" mean on a field with more than one value? Say I
> have "A" and "B" in the field in a single document. What group does it
> go in, one labeld "A" or one labeled "B"?
>
> So IIUC, rather than do something which will be wrong it throws an
> error if the field is defined as multiValued. And whatever option is
> chosen (e.g. use the min or max or....) will be wrong sometime.
>
> Although admittedly the error is a bit obscure...
>
> Best,
> Erick
>
> On Mon, Feb 26, 2018 at 7:37 AM, Vincenzo D'Amore <v.dam...@gmail.com>
> wrote:
> > Hi Amrit,
> >
> > thanks for your help.
> >
> > I know that only 5/10% of documents in the collection have more than one
> > value for the field I was trying to group by.
> >
> > So there isn't a particular memory usage in this case. Do you know if
> there
> > is any other counter-indication I have to be aware of?
> >
> > I was thinking to avoid this problem hacking the source code and deploy a
> > personalised version of Solr.
> >
> > Best regards,
> > Vincenzo
> >
> >
> >
> > On Mon, Feb 26, 2018 at 3:22 PM, Amrit Sarkar <sarkaramr...@gmail.com>
> > wrote:
> >
> >> Vincenzo,
> >>
> >> As I read the source code; SchemaField.java
> >>
> >> /**
> >> * Sanity checks that the properties of this field type are plausible
> >> * for a field that may be used to get a FieldCacheSource, throwing
> >> * an appropriate exception (including the field name) if it is not.
> >> * FieldType subclasses can choose to call this method in their
> >> * getValueSource implementation
> >> * @see FieldType#getValueSource
> >> */
> >> public void checkFieldCacheSource() throws SolrException {
> >> if ( multiValued() ) {
> >> throw new SolrException(SolrException.ErrorCode.BAD_REQUEST,
> >> "can not use FieldCache on multivalued
> field: "
> >> + getName());
> >> }
> >> if (! hasDocValues() ) {
> >> if ( ! ( indexed() && null != this.type.getUninversionType(this) )
> ) {
> >> throw new SolrException(SolrException.ErrorCode.BAD_REQUEST,
> >> "can not use FieldCache on a field w/o
> >> docValues unless it is indexed and supports Uninversion: "
> >> + getName());
> >> }
> >> }
> >> }
> >>
> >> Seems like FieldCache are not allowed to un-invert values for
> >> multi-valued fields.
> >>
> >> I can suspect the reason, multiple values will eat up more memory? Not
> >> sure, someone else can weigh in.
> >>
> >>
> >>
> >> Amrit Sarkar
> >> Search Engineer
> >> Lucidworks, Inc.
> >> 415-589-9269
> >> www.lucidworks.com
> >> Twitter http://twitter.com/lucidworks
> >> LinkedIn: https://www.linkedin.com/in/sarkaramrit2
> >> Medium: https://medium.com/@sarkaramrit2
> >>
> >> On Mon, Feb 26, 2018 at 7:37 PM, Vincenzo D'Amore <v.dam...@gmail.com>
> >> wrote:
> >>
> >> > Hi,
> >> >
> >> > while trying to run a group query on a multivalue field I received
> this
> >> > error:
> >> >
> >> > can not use FieldCache on multivalued field:
> >> >
> >> > <?xml version="1.0" encoding="UTF-8"?>
> >> > <response>
> >> >
> >> > <lst name="responseHeader">
> >> > <bool name="zkConnected">true</bool>
> >> > <int name="status">400</int>
> >> > <int name="QTime">4</int>
> >> > </lst>
> >> > <lst name="error">
> >> > <lst name="metadata">
> >> > <str name="error-class">org.apache.solr.common.SolrException</
> str>
> >> > <str name="root-error-class">org.apache.solr.common.
> >> > SolrException</str>
> >> > </lst>
> >> > <str name="msg">can not use FieldCache on multivalued field:
> >> > categoryLevels</str>
> >> > <int name="code">400</int>
> >> > </lst>
> >> > </response>
> >> >
> >> > I don't understand why this is happening.
> >> >
> >> > Do you know any way to work around this problem?
> >> >
> >> > Thanks in advance,
> >> > Vincenzo
> >> >
> >> > --
> >> > Vincenzo D'Amore
> >> >
> >>
> >
> >
> >
> > --
> > Vincenzo D'Amore
>
--
Vincenzo D'Amore
