ARSER">52.3.1. Parser</a></span></dt><dt><span class="sect2"><a href="parser-stage.html#PARSER-STAGE-TRANSFORMATION-PROCESS">52.3.2. Transformation Process</a></span></dt></dl></dd><dt><span class="sect1"><a href="rule-system.html">52.4. The <span class="productname">PostgreSQL</span> Rule System</a></span></dt><dt><span class="sect1"><a href="planner-optimizer.html">52.5. Planner/Optimizer</a></span></dt><dd><dl><dt><span class="sect2"><a href="planner-optimizer.html#PLANNER-OPTIMIZER-GENERATING-POSSIBLE-P