Question

Can a unique key in Solr/Lucene schema be text_general instead? I have tried that but Solr doesn’t overwrite the data, it simply adds another row hence duplicating the data.

I have commented out following from solrconfig.xml

<searchComponent name="elevator" class="solr.QueryElevationComponent" >
<!-- pick a fieldType to analyze queries -->
<str name="queryFieldType">string</str>
<str name="config-file">elevate.xml</str>
</searchComponent>

My schema.xml has

<uniqueKey>_id</uniqueKey>
<field name="_id" type="text_general" indexed="true" stored="true" default="NEW"/>

Any help would be greatly appreciated.

Answer 1

You can use whatever type you want for the uniqueKey field. As you can read from the documentation:

The declaration can be used to inform Solr that there is a
field in your index which should be unique for all documents. If a
document is added that contains the same value for this field as an
existing document, the old document will be deleted.

It is not mandatory for a schema to have a uniqueKey field.

Note that if you have enabled the QueryElevationComponent in
solrconfig.xml it requires the schema to have a uniqueKey of type
StrField. It cannot be, for example, an int field.

What’s important is that your uniqueKey field is unique, meaning that the same document has the same identifier. Only that way the replace if existing mechanism can work. Using an uuid field type you’d never replace a document because you would have a different id for each one, automatically.