In 9.1:
regression=# select pg_size_pretty(8*1024*1024);
pg_size_pretty
----------------
8192 kB
(1 row)
In HEAD:
regression=# select pg_size_pretty(8*1024*1024);
ERROR: function pg_size_pretty(integer) is not unique
LINE 1: select pg_size_pretty(8*1024*1024);
^
HINT: Could not choose a best candidate function. You might need to add explicit type casts.
The argument for adding pg_size_pretty(numeric) was pretty darn thin in
the first place, IMHO; it does not seem to me that it justified this
loss of usability.
regards, tom lane