Hm, none of the answers so far have gone into detail pedantically enough for me tonight. Here's an gutsier explanation that is mostly true.

It depends on whether that's a global variable or a lexical variable. Perl doesn't optimize away any used variable names completely, but it does only store a single copy of lexical variable names in the appropriate lexical pad. All lexical variable accesses involve indexed lookups into the appropriate lexical value pad.

Global symbols are different, and the appropriate op in the optree keeps around the name of the symbol for a runtime lookup. That means if you refer to a global variable three times in your program, you'll have at least three more copies of its name in memory.

In reply to Re: Does the size of a variable's name affect memory? by chromatic
in thread Does the size of a variable's name affect memory? by nmerriweather

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.