As of today when we run an update to blazegraph we only extract the total number of mutations performed.
But the current update process runs between 5 and 7 update queries in one request. Having numbers about how each query performed might be interesting, esp. to answer some of the question asked in T239687.
The goal is to make org.wikidata.query.rdf.tool.rdf.RdfRepository#syncFromChangesNonMerging reports all the known metrics for all the individual update requests we send in this batch.
Because blazegraph only reports HTML for update response something similar to org.wikidata.query.rdf.tool.rdf.client.UpdateCountResponse will have to be added.