$a=[@$a] can be used to shrink the array. (Well, create a new one the minimal size.) 

$ perl -MDevel::Peek -e'push @$a, $_ for qw( a b c d e ); Dump($a,1); 
+$a=[@$a]; Dump($a,1);'
SV = IV(0x817bc44) at 0x817bc48
  REFCNT = 1
  FLAGS = (ROK)
  RV = 0x816c158
  SV = PVAV(0x816d1c8) at 0x816c158
    REFCNT = 1
    FLAGS = ()
    ARRAY = 0x8177928
    FILL = 4                       <-----  5 visible elements
    MAX = 11                       <----- 12 elements allocated
    ARYLEN = 0x0
    FLAGS = (REAL)
SV = IV(0x817bc44) at 0x817bc48
  REFCNT = 1
  FLAGS = (ROK)
  RV = 0x816cea8
  SV = PVAV(0x816d1dc) at 0x816cea8
    REFCNT = 1
    FLAGS = ()
    ARRAY = 0x8183cb8
    FILL = 4                       <-----  5 visible elements
    MAX = 4                        <-----  5 elements allocated
    ARYLEN = 0x0
    FLAGS = (REAL)

[download]

But you might only end up fragmenting your memory, leaving less usable free memory behind.

In reply to Re: array overhead by ikegami
in thread array overhead by Anonymous Monk

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