The "Fulltext Ngram" fieldtype available in the Drupal 8 module Search API Solr (which enables partial-word matching) does not seem to work with an Acquia Search backend.
Pick the Solr configuration file set for your Acquia Search Solr cores that is compatible with Search API Solr:
- Log into the Acquia Cloud UI
- Go to Applications > [your application name] > Acquia Search > "Edit"
- Under "Acquia Search configuration set", pick the one compatible with Search API Solr 8.x-1.x. Screenshot below:
- Do wait a few minutes for changes to be deployed into the Acquia Search Solr instance.
- From your Drupal site, trigger a full reindex, and after finishing, do wait a few more minutes (3-5) for the index changes to become available in queries.
- Clear your Drupal caches. Clearing your Varnish cache is also recommended.
Additionally, remember that any Drupal View that tries to query this "Fulltext NGram" fieldtype should have this setting within any Fulltext Search filter:
Previously-available Solr configuration files crafted by the Drupal community did not properly implement NGram fields. See Drupal.org issue #2896432.