In HAWQ, you can use GPORCA or the legacy query optimizer.
Note: To use the GPORCA query optimizer, you must be running a version of HAWQ built with GPORCA, and GPORCA must be enabled in your HAWQ deployment.
These sections describe GPORCA functionality and usage:
GPORCA extends the planning and optimization capabilities of the HAWQ legacy optimizer.
GPORCA includes enhancements for specific types of queries and operations:
Precompiled versions of HAWQ that include the GPORCA query optimizer enable it by default, no additional configuration is required. To use the GPORCA query optimizer in a HAWQ built from source, your build must include GPORCA. You must also enable specific HAWQ server configuration parameters at or after install time:
To execute queries optimally with GPORCA, consider certain criteria for the query.
When GPORCA is enabled, you can determine if HAWQ is using GPORCA or is falling back to the legacy query optimizer.
When GPORCA is enabled, HAWQ’s behavior changes. This topic describes these changes.
There are limitations in HAWQ when GPORCA is enabled. GPORCA and the legacy query optimizer currently coexist in HAWQ because GPORCA does not support all HAWQ features.