This is an option consistent with what the other tools of src/bin/
(pg_checksums, pg_dump, pg_rewind and pg_basebackup) provide which is
useful for leveraging the I/O effort when testing things. This is not
to be used in a production environment.
All the regression tests of pg_upgrade are updated to use this new
option. This happens to cut at most a couple of seconds in environments
constrained on I/O, by avoiding a flush of data folder for the new
cluster upgraded.
Author: Michael Paquier
Reviewed-by: Peter Eisentraut
Discussion: https://postgr.es/m/YbrhzuBmBxS/DkfX@paquier.xyz
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