I performed a full merge, along with Contents file and here are the
statistics I've gathered:

All python/shell processes used 4 CPU threads.
For the Contents files, memory usage can get high and we should see what
to do about it. I think it maxed out at 6GB or so of RAM usage.

Time to download entire spooldir (devuan+debian+debian-security):
advertised 100mbit connection

        total time: 964.9163410663605
        size: 2.2G

Time to merge Contents in all suites+categories+architectures (python):
didn't merge Contents-sources because i failed

        total time: 2921.5137088298798
        size: 1002M

Time to merge Contents in all suites+categories+architectures (shell script):

        real    106m50.168s
        user    388m18.720s
        sys     22m12.016s

Time to merge all repositories after that (including generation of Releases):
with Contents:

        total time: 484.9617745876312
        size (with contents): 1.4G
        size (w/o  contents): 400M

        (this size should be multiplied by 3 if we want 3-dir rotation)

Initial incremental update which also does a full rsync the first time:
3-dir rotation:

        update check (no updates): total time: 8.535353660583496
        rsync to merged-production + rsync to merged-staging:

        real    1m0.351s
        user    0m19.372s
        sys     0m11.016s

total minutes (roughly):
    16.1 (initial spool download)
    48.7 (contents.gz merge)
     8.1 (Packages merge + release generation)
     1.0 (full rsync)
    ----
    73.9

total size of the amprolla directory after this:
    6.3G

--
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