Of course, 'sort' has to either read everything in before producing any output (since the last line read could sort to the front), or do a bunch of seeking around and re-reading. Even if sort reads everything into mem, you probably still win because the perl scalars were bigger than the lines sort was holding in memory.

But the real issue is: "Why use a disk-based hash store when you need to process the keys in sorted order?" (Do you need to process them in sorted order?)

If your keys are sequential, a simple fixed-length record file allows very good performance (you can add new keys to the end, and read a value with a single seek+read).

If your keys are more complex, I'd bring in an external indexing engine in the form of a db such as SQLite (or mysql, or postgres, or...).

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.