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Above we said "don't use Solr itself as a datasource" ... but one way to deal with data availability problems is to set up a completely separate Solr install with a config designed for ONLY data storage, not searching. The schema would have stored="true", indexed="false", and docValues="false" for all fields, and would only use basic types like int, long, date, uuid, and string. It would not have any copyFields. You would need to make sure that the separate Solr install receives all new documents and changes that are applied to your primary Solr installation.
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