Solr checks if the index is up to date at each startup but it does the indexing only once. I see in your log that it’s indexing " 2804 documents added, 2801 deleted and 2 updated during the synchronization of the Solr index.". That’s ok and not a lot and shouldn’t take long. If it takes long there’s a problem on your system. Also, once it’s done they won’t be reindexed.