For a list implementation of event items I thought it handy to use the Examine ExternalIndexSet and an ExternalSearcher in order to speedily fetch lists of events. the index configuration looks like:

<ExamineIndexProviders>
 <!-- default external indexer, which excludes protected and unpublished pages-->
    <add name="ExternalIndexer" type="UmbracoExamine.UmbracoContentIndexer, UmbracoExamine"
        enableDefaultEventHandler="true"
        supportUnpublished="false"
        supportProtected="false"
    />

</providers>
 </ExamineIndexProviders>
 <ExamineSearchProviders defaultProvider="ExternalSearcher">
 <providers>
   <add name="ExternalSearcher" type="UmbracoExamine.UmbracoExamineSearcher, UmbracoExamine" 
   indexSet="ExternalIndexSet" />
</ExamineSearchProviders>

This is working perfectly, but with one big issue: whenever a node is unpublished, the Searcher keeps giving it back until the web app is restarted!

After some investigation, I see that the node which is unpublished, is actually trying to get processed in the Examine index:

INFO  Umbraco.Core.Publishing.PublishingStrategy - Content 'blabla' with Id '14384' has been unpublished.
DEBUG Umbraco.Core.Sync.ServerMessengerBase - Invoking refresher Umbraco.Web.Cache.PageCacheRefresher on local server for message type RemoveByInstance
DEBUG Umbraco.Web.PublishedCache.XmlPublishedCache.XmlCacheFilePersister - Touched, was released...
DEBUG Umbraco.Web.PublishedCache.XmlPublishedCache.XmlCacheFilePersister - Create new...
DEBUG Umbraco.Web.Scheduling.BackgroundTaskRunner - [XmlCacheFilePersister] Task added Umbraco.Web.PublishedCache.XmlPublishedCache.XmlCacheFilePersister
DEBUG Umbraco.Web.PublishedCache.XmlPublishedCache.XmlCacheFilePersister - Created, save in 4000ms.
DEBUG UmbracoExamine.DataServices.UmbracoLogService - DeleteFromIndex with query: __Path:\-1\,*14384\,* (found 0 results), Provider=ExternalIndexer, NodeId=14384
DEBUG UmbracoExamine.DataServices.UmbracoLogService - Index deleted for term: __NodeId with value 14384, Provider=ExternalIndexer, NodeId=-1
DEBUG UmbracoExamine.DataServices.UmbracoLogService - ReIndexNode with type: content, Provider=InternalIndexer, NodeId=14384
DEBUG UmbracoExamine.DataServices.UmbracoLogService - AddSingleNodeToIndex with type: content, Provider=InternalIndexer, NodeId=14384
DEBUG UmbracoExamine.DataServices.UmbracoLogService - Index created for node 14384, Provider=InternalIndexer, NodeId=14384
DEBUG Umbraco.Web.PublishedCache.XmlPublishedCache.XmlCacheFilePersister - Timer: release.
DEBUG Umbraco.Web.PublishedCache.XmlPublishedCache.XmlCacheFilePersister - Run now (sync).
umbraco.content - Save Xml to file...
umbraco.content - Saved Xml to file.
Umbraco.Web.Scheduling.ScheduledTasks - Scheduled tasks executing
DEBUG Umbraco.Web.Scheduling.KeepAlive - Keep alive executing
DEBUG Umbraco.Web.Scheduling.ScheduledTasks - Scheduled tasks complete (took 0ms)

As you can see, a delete is triggered, so that appears fine. What I do see in the backend is that when I go to the Examine Management section and to the specific index, I see that Has Deletions? is set to true and then the number of deleted nodes are next to it.

These deletions are then set to 0 when I click Optimize Index. However - even after optimizing, the node is still present in the search results until I restart the web app or rebuild the index!

Then I checked my code and I do something very simple:

var externalSearcher =
        ExamineManager.Instance.SearchProviderCollection["ExternalSearcher"];

        var criteria = externalSearcher.CreateSearchCriteria();


        var query = olderOrNewer.Equals("older")
            ? criteria.NodeTypeAlias("agendaItem").And().Range("eventSortDate", DateTime.MinValue, fromDateTime)
                .And()
                .OrderByDescending("eventSortDate")
            : criteria.NodeTypeAlias("agendaItem").And().Range("eventSortDate", fromDateTime, DateTime.MaxValue).And().OrderBy("eventSortDate");

        var searchResults = externalSearcher.Search(query.Compile(), maxItems);

As far as I know, I'm not holding any reference to a search collection.

Can anyone tell me what I'm doing wrong?