sedusedan,

I didn't previously think about the consequences of slide #4, but it probably is why I don't 'flock' the actual file. I use a dummy file called ".../LOCK", that I use 'flock' to lock/unlock. This file is alway of length '0', so that allows the actual file that I'm writing/reading to continue to be buffered. You have to use it the exact same way. ('LOCK_EX' for write, 'LOCK_SH' for read.)

As long as you're preventing the race condition by always 'flock'ing the dummy file, you will not get into trouble. Early on I found problems with 'flock'ing the actual file, which may be why 'flock' was fixed to eliminate the problem described in slide #4. But buffering is good!

I looked at your benchmark, and noticed that you don't delete the file each time your script is entered and before you start the benchmark. Even though you're 'open'ing the file with append, you may distort the results due to more disk head activity by having a larger and larger file with each additional call. I adjusted your script and did a comparison to 'syslog' and found that 'syslog' was about twice as slow. I'm guessing that is the socket activity between different processes.

Anyway, looks like you have a plan.

Good Luck...Ed

"Well done is better than well said." - Benjamin Franklin

In reply to Re^3: Safe to open+close for every write, with locking? by flexvault
in thread Safe to open+close for every write, without locking? by sedusedan

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.