Tom Lane wrote:
FWIW, Postgres has already switched over from shipping the raw tzdb text files in our tarball to shipping tzdata.zi, precisely because it's a lot smaller and you get the same output after running it through zic.
Thanks for letting me know. I have a version-related question about that. zishrink.awk currently avoids some optimizations (and thus generates a longer file than it could) for compatibility with zic 2017b and earlier. I was thinking of enabling those optimizations in a few months, on the theory that tzdata.zi is a relatively new feature and anybody who's using it is also using a newer zic. So my question is: does "running it through zic" mean running tzdata.zi through the system zic (which is not always present, and which may predate 2017b), or does it mean running tzdata.zi through your own copy of zic? If the former, then I suppose we should wait a few years before adding those optimizations to zishrink.awk. If the latter, then I hope we can shrink tzdata.zi a bit in a few months rather than waiting until 2022.