Oracle Database 18C new features for DBA - 1
DBMS_SESSION.SLEEP Oracle Database 18C
In Oracle Database 18C very popular popular procedure DBMS_LOCK.SLEEP is also available in package DBMS_SESSION.
OPTIMIZER_IGNORE_HINTS Oracle Database 18C
In 18C release optimizer parameter OPTIMIZER_IGNORE_HINTS(was underscore parameter) is now documented.
If set to TRUE the optimizer ignores embedded hints. Can be changed on system or session level.
Qualified expressions for PL/SQL Oracle Database 18C
In Oracle Database 18C type initialization is simplified with qualified expressions for Record type and Associative Array Type. It can help simplify coding.
Record
rec_var := (field_name => some_value, .., field_name => some_value)
Associative Array
rec_var := (1 => some_value, .., 10 => some_value)
Private Temporary Tables Oracle Database 18C
New type of temporary tables appeared in 18C called Private Temporary Tables. They are temporary database objects that are dropped at the end of a transaction or session. Private temporary tables are stored in memory and each one is visible only to the session that created it.
CREATE PRIVATE TEMPORARY TABLE .... ON COMMIT DROP DEFINITION
or
CREATE PRIVATE TEMPORARY TABLE .... ON COMMIT PRESERVE DEFINITION
DROP DEFINITION This creates a private temporary table that is transaction specific. All data in the table is lost, and the table is dropped at the end of transaction.
PRESERVE DEFINITION This creates a private temporary table that is session specific. All data in the table is lost, and the table is dropped at the end of the session that created the table.
Schema Only Accounts Oracle Database 18C
New type of schema can be created in 18C where user has no password.
CREATE USER username NO AUTHENTICATION;
Scalable sequences Oracle Database 18C
Sequence is commonly known oracle object that is used to generate numbers in specified orders. In Oracle 18C new extra words can be defined for sequence creation:
SCALE | NOSCALE(default)
EXTEND | NOEXTEND(default)
Cancel SQL statement Oracle Database 18C
In latest version of database 18C instead of killing user session you can cancel its currently running or opened SQL statement using the ALTER SYSTEM CANCEL SQL statement.
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