About GPORCA

About GPORCA

In Greenplum Database 4.3.5.0 and later, GPORCA co-exists with the legacy query optimizer.

These sections describe GPORCA functionality and usage:

  • Overview of GPORCA
    GPORCA extends the planning and optimization capabilities of the Greenplum Database legacy optimizer.
  • Enabling GPORCA
    By default, Greenplum Database uses the legacy query planner. Server configuration parameters enable or disable GPORCA.
  • Collecting Root Partition Statistics
    For a partitioned table, GPORCA uses statistics of the table root partition to generate query plans. These statistics are used for determining the join order, for splitting and joining aggregate nodes, and for costing the query steps. This is in contrast to the legacy planner, which uses the statistics of each leaf partition. If you execute queries on partitioned tables, you must collect statistics on the root partition and periodically update those statistics to ensure that GPORCA can generate optimal query plans.
  • Considerations when Using GPORCA
    To execute queries optimally with GPORCA, query criteria to consider.
  • GPORCA Features and Enhancements
    GPORCA, the Greenplum next generation query optimizer, includes enhancements for specific types of queries and operations:
  • Changed Behavior with the GPORCA
    There are changes to Greenplum Database behavior the GPORCA optimizer is enabled.
  • GPORCA Limitations
    There are limitations in Greenplum Database 4.3.5.0 and later when GPORCA is enabled. The Pivotal Query Optimizer and the legacy query optimizer currently coexist in Greenplum Database 4.3.5.0 and later because GPORCA does not support all Greenplum Database features.
  • Determining the Query Optimizer that is Used
    When GPORCA is enabled, you can determine if Greenplum Database is using GPORCA or is falling back to the legacy query optimizer.
  • About Uniform Multi-level Partitioned Tables
Parent topic: Querying Data