Pnnn—the Parallel Query process
Parallel Query processes are responsible for executing SQL statements to perform the following actions:
Parallel query
Parallel index creation
Parallel data loading
Parallel CREATE TABLE AS SELECT...
When the Oracle instance is started, the number of Parallel Query processes specified by the INIT.ORA parameter PARALLEL_MIN_SERVERS will be started. If the volume of SQL statements being processed requires additional Pnnn processes, they will be created up to the value of the INIT.ORA parameter PARALLEL_MAX_SERVERS. As Pnnn processes become idle for the period of time specified by the INIT.ORA parameter PARALLEL_SERVER_IDLE_TIME, they will be terminated until only PARALLEL_MIN_SERVERS processes remain. If no additional Pnnn processes can be created because PARALLEL_MAX_SERVERS has been reached, then additional queries will be processed in non-parallel (sequential) mode.
Get Oracle Database Administration: The Essential Refe now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
