Investigate why reading the journal of the content table takes so long
When running the last dataset export, the directory table was read from the journal reasonably fast, but the content table had a gigantic ETA. This is especially strange because the content exporter does almost nothing (single write per node).
We should find out if that always happens, even with a dummy exporter that does nothing. If it does, then it's likely a problem in the journal.
Migrated from T3021 (view on Phabricator)