5.2.2.6 Managing Fast File Creation

Oracle Exadata System Software features fast file creation, allowing accelerated initialization of data files.

This feature automatically runs whenever you create a new tablespace, add a data file to an existing tablespace, or autoextend an existing tablespace. Oracle Exadata System Software can initialize files very quickly because it issues many concurrent I/O requests. However, these concurrent I/O requests create a heavy load that can interfere with performance-critical queries.

Using I/O Resource Management (IORM), you can control the priority of fast file creations for creating a new tablespace or adding a data file to an existing tablespace. These operations are run under the FASTFILECRE function. By default, the FASTFILECRE function is mapped to a hidden consumer group that has lower priority than all consumer group and background I/Os. If you choose to increase the priority, and thereby performance, of file creations, add a mapping rule based on the mapping attribute DBMS_RESOUCRE_MANAGER.ORACLE_FUNCTION, and mapping value FASTFILECRE.

Because autoextending an existing tablespace is a brief and often time-critical operation, you cannot modify its priority using IORM.

Example 5-7 Managing Fast File Creation

This example shows how to run fast file creations in the MAINTENANCE_GROUP consumer group.

BEGIN
DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
DBMS_RESOURCE_MANAGER.CREATE_CONSUMER_GROUP('MAINTENANCE_GROUP', 'Maintenance
activity');
DBMS_RESOURCE_MANAGER.SET_CONSUMER_GROUP_MAPPING(DBMS_RESOURCE_MANAGER.ORACLE_
FUNCTION, 'FASTFILECRE', 'MAINTENANCE_GROUP');
DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
END;
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