Thread:Extension talk:SolrStore/Probe connectivity to the Solr host/reply (2)

Actually for the case above, Solr was not available because the server was restarted. Not sure about the inner working of Solr but certainly their must be method to check if Solr is ready to receive index values and in case it is not return true for the hook and marked the document as non-indexed.

Normally for any indexing services, you would have to have a status table on which one can track the current status of those documents, while I'm sure you don't want to introduce any special handling nor create a additional status table you could instead trace the status by creating a meta-subobject (with a special property) which is created and annotated to an entity (page) in case the status returns with anything other than successful. So either one can run a #ask query to find those subobjects or a special status page can pick those, display and allow for a mass re-index because running Special:SWMAdmin is not alwasy the best option (in our case we have around 1.1M triples which makes every Special:SWMAdmin run very costly).