6) Possibly relevant is that this module is running in multiple processes, potentially at the same time. But simultaneous reads should not be a problem....

Oh, to further clarify, checking seek() return should be on the all the seeks, the "dummy seek to the same position" shouldn't fail. Of course "shouldn't" doesn't mean that it couldn't! Normally tell() should do same "under the covers" thing and yield the current byte position to check against "legal byte positions". You can put an "or die "xxxx" " on all seek(),tell()'s. I was mainly concerned that sometimes perhaps you seek past EOF or before BOF and all sorts of "bad" things could happen, some of them non-obvious.

With a failure 1/1,000 operations, this is seldom enough that there isn't some super obvious thing, but it is often enough to be able to re-create the problem in some "reasonable time frame". I presume some hours or even minutes.

One question I have is: Are you able to recreate the problem with only one process running? An overnight run with many thousand's queries without errors with one process might be a clue.

I have certainly opened the same file from multiple process and used read sequential many times...a normal sort of thing to do. I am wondering if somehow on your system, somehow the seeks() are causing problems. I suppose that it is possible that your code is fine and the OS and its file system occasionally goofs.

I have done what you are trying to do, but my thing that did the seeking, reading, writing was just a single process.

In reply to Re^3: Buffered IO and un-intended slurping by Marshall
in thread Buffered IO and un-intended slurping by Wiggins

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.