This could all be a single scalding job eventually.

First, run matchcrossref and dumpfilemeta, and copy the output down to an SSD
somewhere.

    bnewbold@ia601101$ zcat 2018-09-14-0559.05-dumpfilemeta.tsv.gz | wc -l
    30728100

Reduce down the scored matches to just {sha1, dois}, sorted:

    zcat 2018-08-27-2352.17-matchcrossref.tsv.gz | ./filter_scored_matches.py | pv -l | sort > 2018-08-27-2352.17-matchcrossref.filtered.tsv
    # 5.79M 0:18:54 [5.11k/s]

Join/merge the output:

    zcat 2018-09-14-0559.05-dumpfilemeta.tsv.gz | LC_ALL=C join -t$'\t' 2018-08-27-2352.17-matchcrossref.filtered.tsv - | pv -l | ./enrich_scored_matches.py | gzip > 2018-08-27-2352.17-matchcrossref.insertable.json.gz
    # 5.79M 0:09:09 [10.5k/s]