This is somewhat similar to what I would suggest, except that instead of marking certain records as having been deleted, I'd keep two pointers into the file, one for read and one for write, then go through the entire file line by line reading and writing, but just not writing if I find one of the unwanted serial numbers. This approach will involve reading the whole file (but only a line at a time, so won't need much memory) and writing the whole file, so will take just as much time as writing the wanted lines to a new file and then renaming it, but it won't require 380GB of intermediate storage.

Don't forget to truncate() the file when you've finished writing the last record, or you'll end up with rubbish tacked onto the end.

In reply to Re^2: 15 billion row text file and row deletes - Best Practice? by DrHyde
in thread 15 billion row text file and row deletes - Best Practice? by awohld

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.