use Devel::Peek;

my $n = 1_000_000;

my @q;
for ( 1 .. $n ) {
   push @q, undef;
   shift @q;
}

Dump( @q );

##</code><code>##

SV = PVAV(0x5588bbfb50c0) at 0x5588bbfe31b8
  REFCNT = 1
  FLAGS = ()
  ARRAY = 0x5588bbfee1d0 (offset=4)
  ALLOC = 0x5588bbfee1b0
  FILL = -1
  MAX = -1
  FLAGS = (REAL)