title: Am I using plyr right? I seem to be using way too much memory
body: <p>I have the following, somewhat large dataset:</p>
  
  <pre><code> &gt; dim(dset)
   [1] 422105     25
   &gt; class(dset)
   [1] "data.frame"
   &gt; 
  </code></pre>
  
  <p>Without doing anything, the R process seems to take about 1GB of RAM. </p>
  
  <p>I am trying to run the following code:</p>
  
  <pre><code>  dset &lt;- ddply(dset, .(tic), transform,
                  date.min &lt;- min(date),
                  date.max &lt;- max(date),
                  daterange &lt;- max(date) - min(date),
                  .parallel = TRUE)
  </code></pre>
  
  <p>Running that code, RAM usage skyrockets. It completely saturated 60GB's of RAM, running on a 32 core machine. What am I doing wrong?</p>