<div><h2 class="title" style="clear: both">52.5. Planner/Optimizer <a href="#PLANNER-OPTIMIZER" class="id_link">#</a></h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="planner-optimizer.html#PLANNER-OPTIMIZER-GENERATING-POSSIBLE-PLANS">52.5.1. Generating Possible Plans</a></span></dt></dl></div><p>
    The task of the <em class="firstterm">planner/optimizer</em> is to
    create an optimal execution plan. A given SQL query (and hence, a
    query tree) can be actually 