[SOLR-16588] solr.DenseVectorField fieldType without a knnAlgorithm parameter results in error

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 9.1
• Fix Version/s: 9.1.1
• Labels: vector-based-search
• Assignee: Alessandro Benedetti
• Reporter: Alastair Porter
• Created: 14/Dec/22 09:40
• Updated: 21/Feb/23 10:05
• Resolved: 12/Jan/23 19:01

Description

Following the Dense Vector Search documentation at https://solr.apache.org/guide/solr/latest/query-guide/dense-vector-search.html

 

Using a field definition of 

 

  <fieldType name="knn_vector" class="solr.DenseVectorField" vectorDimension="4" similarityFunction="euclidean"/>
  <field name="vector" type="knn_vector" multiValued="false" stored="true"/>

And then trying to index a document results in an error in solr:

 

 

2022-12-13 19:10:08.763 ERROR (qtp3540494-54) [ x:fsnn] o.a.s.s.HttpSolrCall org.apache.solr.common.SolrException: null KNN algorithm is not supported => org.apache.solr.common.SolrException: null KNN algorithm is not supported
at org.apache.solr.core.SchemaCodecFactory$1.getKnnVectorsFormatForField(SchemaCodecFactory.java:134)
org.apache.solr.common.SolrException: null KNN algorithm is not supported
at org.apache.solr.core.SchemaCodecFactory$1.getKnnVectorsFormatForField(SchemaCodecFactory.java:134) ~[?:?]
at org.apache.lucene.codecs.lucene92.Lucene92Codec$3.getKnnVectorsFormatForField(Lucene92Codec.java:101) ~[?:?]
at org.apache.lucene.codecs.perfield.PerFieldKnnVectorsFormat$FieldsWriter.getInstance(PerFieldKnnVectorsFormat.java:148) ~[?:?]
at org.apache.lucene.codecs.perfield.PerFieldKnnVectorsFormat$FieldsWriter.writeField(PerFieldKnnVectorsFormat.java:107) ~[?:?]
at org.apache.lucene.index.VectorValuesWriter.flush(VectorValuesWriter.java:145) ~[?:?]
at org.apache.lucene.index.IndexingChain.writeVectors(IndexingChain.java:461) ~[?:?] 

This appears to be related to the changes introduced in SOLR-16245

 

Adding a parameter knnAlgorithm="hnsw" to the fieldType definition causes the indexing process to work as expected

Issue Links

• links to: GitHub Pull Request #1255