You can do this by combining the builtin update processors.
Add this to your solrconfig:
<updateRequestProcessorChain name="composite-id">
<processor class="solr.CloneFieldUpdateProcessorFactory">
<str name="source">docid_s</str>
<str name="source">userid_s</str>
<str name="dest">id</str>
</processor>
<processor class="solr.ConcatFieldUpdateProcessorFactory">
<str name="fieldName">id</str>
<str name="delimiter">--</str>
</processor>
<processor class="solr.LogUpdateProcessorFactory" />
<processor class="solr.RunUpdateProcessorFactory" />
</updateRequestProcessorChain>
Add documents such as:
curl
"http://localhost:8983/solr/update?commit=true&update.chain=composite-id"; \
-H 'Content-type:application/json' -d '
[{"title": "Hello World",
"docid_s": "doc-1",
"userid_s": "user-1",
"comments_ss": ["Easy", "Fast"]}]'
And get results like:
"title":["Hello World"],
"docid_s":"doc-1",
"userid_s":"user-1",
"comments_ss":["Easy",
"Fast"],
"id":"doc-1--user-1",
Add as many fields in whatever order you want using "source" in the clone
update processor, and pick your composite key field name as well. And set
the delimiter string as well in the concat update processor.
I managed to reverse the field order from what you requested (userid,
docid).
I used the standard Solr example schema, so I used dynamic fields for the
two ids, but use your own field names.
-- Jack Krupansky
-----Original Message-----
From: Rishi Easwaran
Sent: Tuesday, May 28, 2013 11:12 AM
To: solr-user@lucene.apache.org
Subject: Solr Composite Unique key from existing fields in schema
Hi All,
Historically we have used a single field in our schema as a uniqueKey.
<field name="docid" type="string" indexed="true" stored="true"
multiValued="false" required="true"/>
<field name="userid" type="string" indexed="true" stored="true"
multiValued="false" required="true"/>
<uniqueKey>docid</uniqueKey>
Wanted to change this to a composite key something like
<uniqueKey>userid-docid</uniqueKey>.
I know I can auto generate compositekey at document insert time, using
custom code to generate a new field, but wanted to know if there was an
inbuilt SOLR mechanism of doing this. That would prevent us from creating
and storing an extra field.
Thanks,
Rishi.
