<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE topic PUBLIC "-//OASIS//DTD DITA Composite//EN" "ditabase.dtd"><topicid="topic38"xml:lang="en"><titleid="in198679">Query Performance</title><abstract><shortdesc>Greenplum Database dynamically eliminates irrelevant partitions in a table and optimally allocates memory for different operators in a query.</shortdesc>These enhancements scan less data for a query, accelerate query processing, and support more concurrency.</abstract><body><ul><liid="in198681">Dynamic Partition Elimination<p>In Greenplum Database, values available only when a query runs are used to dynamically prune partitions, which improves query processing speed. Enable or disable dynamic partition elimination by setting the server configuration parameter <codeph>gp_dynamic_partition_pruning</codeph> to<codeph>ON</codeph> or <codeph>OFF</codeph>; it is <codeph>ON</codeph> by default.</p></li><liid="in198822">Memory Optimizations<p>Greenplum Database allocates memory optimally for different operators in a query and frees and re-allocates memory during the stages of processing a query.</p></li></ul>
<note>Greenplum Database uses GPORCA, the Greenplum next generation query optimizer, by default. GPORCA extends the planning and optimization capabilities of the Greenplum Database legacy optimizer. For information about the features and limitations of GPORCA, see <xrefhref="query-piv-opt-overview.xml"/>.</note>
