18c

This post gives a summary of 18c new Memoptimized Rowstore feature. Feature Summary The memoptimized rowstore provides the capability of fast lookup of data for the tables that are mainly queried based on primary key columns. The memoptimized rowstore uses a memory area in the system global area (SGA) called the memoptimize pool that stores the hash indexes of the tables when enabled for fast lookup. Fast lookup is enabled by a hash index structure in the memoptimize pool that provides … [Read more...] about Oracle Database 18c New Feature – Memoptimized Rowstore

This post is a short note on merging partitions and subpartitions online. The below sample demonstration shows you how to merge partitions online while there are concurrent transactions going on. For the purpose of this post, we will create a sample table and load some sample data into it to perform the merge. 1. Create A table Let's create a sample table "onlinemergepartition" as shown below. --- Creating a table CREATE TABLE onlinemergepartition ( pid number, salesdate date, price … [Read more...] about Oracle Database 18c : How to Merge Partitions And Subpartitions Online

In the database versions before 18c, PDB could not be duplicated. Users could only duplicate CDBs. But starting with Oracle database 18c, users can now duplicate one PDB into another CDB. This post gives an example of how to do it. Example Environment Here is an example of how to duplicate PDB from one CDB to another CDB. Let's say that we have the following CDB on both source site and dest site: Source: hostname: test001.tst.com CDB: ORC181U01 PDB: pdb01 Dest: hostname: … [Read more...] about Example of PDB Level Duplication in Oracle Database 18c

Starting 18.1 database, "Scalable Sequences" have been introduced. The ability to create Scalable Sequences has been added to improve the performance of data loading into tables having sequence values as keys. This feature provides the option to add instance and session offsets to significantly reduce the possibility of sequence and index block contention when loading data across RAC instances and multiple loading processes within single instances. The new business benefit is that it further … [Read more...] about Oracle Database 18c new feature – Scalable Sequences

The idea of this post is to explain the steps to cancel a query in Oracle Database 18c. In this version, you have the option to cancel just the query instead of terminating the session. The following clauses are required in an "ALTER SYSTEM CANCEL" SQL statement: SID – Session ID SERIAL – Session serial number Here is an example: 1. Find SID and SERIAL# Let us first find the SID and SERIAL# for the query to be cancelled. ##### Session 1 ##### SQL> select sid, serial# from … [Read more...] about How To Cancel A SQL Query In Oracle Database 18c

Typically, when rolling forward a physical standby database using primary incremental backup, multiple steps are required: Identify the Start SCN on Standby for performing incremental backup on primary Perform incremental backup on primary with FROM SCN clause Move the backup-pieces from primary to standby Catalog the backup-piece on Standby Perform recovery on standby using recover database noredo Refresh standby controlfile again from primary Starting from 12.1, we could use … [Read more...] about Oracle Database 18c: Roll Forward Physical Standby Using RMAN Incremental Backup in Single Command