Hi all,
I was recently writing a log parser and discoverd a large memory leak in my code. When I found the problem I was rather surprised. Hopefully someone can explain the details to me.
Here's where the leak was:
while (my $line = <FILE>) { ... }
I fixed it with the following:
while (<FILE>) { my $line = $_; ... }
Apparently in the first example a new block of memory was being allocated to each $line, but was never reclaimed. I was unable to determine whether perl ever reclaimed the memory, reclaimed after the end of the loop, or at the end ot the process. According to top (on FreeBSD) the memory was never reclaimed, but that could just be a peculiarity of how top reports memory usage.
I always thought the above two lines were functionally and lexically identical. Can anyone explain why they behave differently?
Thanks,
-M
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.
|