This is mostly a question. My impression is that flushing your buffers doesn't mean that the data has been written to the storage medium. But it does mean that the data is visible to other processes. So if another process goes to run after you've flushed your buffers, that data may not be on the storage medium but the other process should end up reading your data from the OS cache.

So you can still have a problem if, for example, the power fails after you get your sequence number. But delaying the unlocking doesn't help that case anyway.

I just noticed that merlyn made a good point about the danger of your read-cache being stale, but I don't think that applies in this particular case.

So my impression is that the explicit unlock isn't actually a problem in this specific case. I agree that it is a good thing to avoid as a general principle.

So my question is "Am I missing something?" I don't want to detract from the good points made. But I'm hoping for validation or specific refutation of my understanding here.

        - tye (but my friends call me "Tye")

In reply to (tye)Re: flock - lordy me.... by tye
in thread flock - lordy me.... by agoth

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.