See SOLR-13132

Deployment

Care must be taken in deployment to load classes from the solrplugins jar file before corresponding classes from the stock Solr jar files. This is best accomplished using Jetty's extraClasspath method to affect the load order of jar files within Jetty, adding the following child element:

  <Set name="extraClasspath">${path_to}/facet-cache-solr-7.5.0.jar</Set>

to the Solr Jetty WebAppContext configuration. The relevant config file in the standard Solr distribution is server/contexts/solr-jetty-context.xml. The path is rooted at /opt/solr/ in the stock Solr docker image.

Facet cache configuration

To configure the facetCache, add the following cache config to your solrconfig.xml:

<cache name="termFacetCache"
       class="solr.search.LRUCache"
       size="200"
       initialSize="200"
       autowarmCount="200"
       regenerator="solr.request.TermFacetCacheRegenerator" />