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Solr Indexing And The Unique Key Field

If you encounter problems with Solr indexing and inconsistencies in the actual indexing - you might have a problem with the Solr unique key field.

If you index items that may have the same id, and this id is used as the unique key in Solr - then you have a problem. Items with the same id's will simply not be tolerated in the Solr index, thus the latter item overwrites the former when indexing. Of course, this is a default and correct behaviour from Solr.

However - this is easy to solve. You just have to use the UUID (Universal Unique Identifier) field type in Solr.

In schema.config in your Solr conf folder (normally C:/solr/conf or similar), add the UUID type, like this:

<fieldType name="uuid" class="solr.UUIDField" indexed="true" />

Then, add a field of this type (still in schema.config):

 <field name="uid" type="uuid" indexed="true" stored="true"
	default="NEW" />

Finally, make sure to point out this field as the unique key, in schema.config:


All done! Now all your indexed items will have a unique ID.

Here's more documentation on Solr and the UniqueKey field.


Thanks for the post. But when I tried this I am getting configuration error that QueryElevationComponent requires the schema to have a uniqueKeyField implemented using StrField .I am using solr 1.4

Please help

at the moment QueryElevationComponent requires a string unique key. This limitation is documented in the Solr wiki.

see :

Is it possible to make a field unique key without it being a 'uuid' and just text_general?

Juzer Ali: As long as it's truly unique it should work, I think.

As your tutorial

Solr apach exception error: uniqueKey field (null) can not be configured with a default value (NEW)

same error with me like Panpic

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