Picking up on point 2 in combination with 12.2, Franck Pachot blogged about a
notable change in behaviour a couple of days ago:
12.2 may not run (the expected) login.sql from SQL*Plus
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> on behalf
of Mark W. Farnham <mwf@xxxxxxxx>
Sent: 18 April 2017 08:18
To: gogala.mladen@xxxxxxxxx; 'Sandra Becker'
Subject: RE: SQL result formatting on TO_CHAR different in 12c
1) Put user defined views casting the columns to your desired widths (a
bunch of objects at 30 instead of new larger sizes)
2) Put column definitions for sqlplus in your glogin.sql or login.sql for
all the columns you care about
#1 would require you to reference your user views.
#2 should be pretty much transparent unless your new column formats conflict
with what you have already defined. In that case YOUR behavior would be
preserved by leaving incumbent column format definitions in place.