Notes from Sangam18

What is new with Oracle 18C:

ATP:

Oracle Autonomous Transaction Processing database<read more>

Single database instance on server  is most efficient and multi-instance on single server is in-efficient model of database build.

Row format storage is ideal for OLTP and column format storage is for analytics.

18c is essentially 12.2.0.2.

Polymorphic Table Functions in Oracle Database 18c:

The return type of a Polymorphic Table Function (PTF) can be determined by input parameters. This differs from conventional table functions, where the output table type is fixed at compile time.

Qualified Expressions in PL/SQL in Oracle Database 18c

Qualified expressions provide and alternative way to define the value of complex objects, which in some cases can make the code look neater.

Scalable Sequences in Oracle Database 18c

Scalable sequences are designed to reduce problems with hot index blocks during large scale data loads into tables with sequence generated primary keys on single instance and RAC databases.

Scalable sequences have been available since the first release of Oracle 12c, but they were not documented and therefore not supported. They are included in the documentation for the first time in Oracle 18c, so they are now a supported feature.

Introduction to In-Memory External Tables in 18c:

approximate Top-N Query Processing (APPROX_RANK, APPROX_SUM, APPROX_COUNT) In Oracle Database 18c

The APPROX_RANK, APPROX_SUM and APPROX_COUNT functions were introduced in Oracle 18c to allow approximate top-n query processing. This extends the approximate query processing that was introduced in the previous two releases (12cR1 and 12cR2)

ALTER SYSTEM CANCEL SQL : Cancel a SQL Statement in a Session in Oracle Database 18c

The basic syntax of the ALTER SYSTEM CANCEL SQL statement is show below.

ALTER SYSTEM CANCEL SQL 'SID, SERIAL[, @INST_ID][, SQL_ID]';

If the INST_ID is omitted, it is assumed you mean the current instance. If the SQL_ID is omitted, it is assumed you mean the SQL that is currently running in the specified session.

Multithreaded Model using THREADED_EXECUTION in Oracle Database 12c Release 1 (12.1)