The "modify it out from under you" problem would be no worse than it is now. Right now anyone could update it in the database while you are working on it, and you won't know unless you re-fetch it. If someone modifies it in the shared cache it's the same, i.e. it won't affect the copy you're working with unless you re-fetch it from the cache (or the database). That's because what you get back from the cache is a copy, not a reference to the item in the cache.

It's possible (and already built into some modules) to use file-locking to provide exclusive access to a cache entry, but that won't really help because multiple machines are involved and the real master source is the database, not the cache.

Another angle would be node-level locks in MySQL based on the code from Apache::Session::Lock::MySQL. May not be worth the effort though.

In reply to Re: Re^6: Recent slowness and outage (IPC cache) by perrin
in thread Recent slowness and outage by tye

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.