Oracle Database 19c Features

 Oracle Database 19c Features

Introduction

Oracle Database 19c is the long term release of the Oracle Database 12c and 18c family of products,it is available on all platformsWindows,Linux,Solaris,HP/UX and AIX as well as the Oracle cloud. Oracle Database 19c offers customers the best performance,scalibility,reliability, and security for all their operational and analytical workloads

Installation

Rpm based Installation install oracle 19c datbase using RPM method

Simlified image based installation of client as well

Upgrades

Auto Upgrade Utility for oracle Database

Docker Container for oracle 19c

Dryrun mode for Gridsetup in clusterware installation

General

Clear Flashback logs from time to time

Passwords removed from user accounts (default accounts)

Flush Metadata Cache for passwords

Multi-model partitioning with hybrid partioning allowing some partitions in database and some as external partitions even in HDFS

New ALTER SYSTEM  statement clause FLUSH PASSWORDFILE_METADATA_CACHE

Hybrid  Partitioned tables - to integerate internal partitions and external partitions  into a single partition table. partitions to reside in both oracle database segments and in external files and sources

Schema-only accounts -Passwords Removed from oracle database accounts  

Database Performance

SQL Quarantine - using Oracle's Resource manager tool is a great way to make sure SQL statements dont become resource hogs and slow down database performance everyone,if a system asks for more system resorces than the DBA allows ,Resources manager kills it,However in existing versions of oracle database,nothing stops users from executing problematic SQL statements again. In oracle 19C ,Resource manager can automatically quarantine the statements, user try to issue once again it wont be run at all

Automatic Indexing

This new feature puts oarcale automation capabilities to work.if oracle 19c thinks a database table would be benifit from an index,the system will automatically create the index and initially mark it as invisible so it cant be used .oracle 19c will then run SQL statements  from your application to see if the index improves query execution you can control this feature  with DBMS_AUTO_INDEX< a new PL?SQL package that's included in 19c

SQL Statement Diagnosability 

SQL Statement Diagnosability with SQL Advisor repair and SQL Test case for procedures

Automatic Database Diagnostic Monitor(ADDM)

ADDM supports for pluggable Database (PDB'S)

Realtime  Statastics For DML Operations

Oracle database 19c intoduces real time statastics which extend online support to conventional DML statements

Automatic Flashback of Standby Database

in prior versions DBA's wanted touse oracle flashback features to return  aprimary database to previous state,In oracle 19c ,a DBA can put the standby database in MOUNT mode with no managed recovery and then flashback the primary one ,the standby will aslo be reverted,thus keeping it in sync with the primary Statistics Collection on custom frequency automatically From 19c database onwards ,High frequency automatic optimizer statastics collection complements the standard statasticscollection job

DataPump

Oracle data pump test mode for transportable tablespace(TTS)

Oracle data pump allows tablespace to stay read -only during TTS import

Oracle data pump import supports more object store credentials

Oracle data pump ability to exclude ENCRYPTION clause on import-new transform  parameter OMIT_ENCRYPTION_CLAUSE

Oracle data pump support for resource usage limitations_new parameter MAX_DATAPUMP_PARALLEL_PER_JOB

Oracle data pump prevents inadvertent use of protected roles-new ENABLE_SECURE_ROLES parameter is available

Oracle data pump loads partitioned table data one operation-GROUP_PARTITION_TABLE_DATA,  new value for the import DATA_OPTIONS Command line paramaeter

Pluggable Databases

Create Duplicate of an oracle database create duplicatedb command , in DBCA silent mode

Ability to relocate a PDB to another CDB using DBCA in silent mode

Create a PDB by cloning a remote PDB using DBCA in silent mode

ADDM Analysis at PDB level

Data Guard

Replicate Restore points from primary to standby

Dynamically change  fast-start- failover (FSFO) target standby database to another standby database in the target list without disabling FSFO

Re-creation of broker configuration

Propagate restore points from primary to standby site

DML redirect to standby/ADG for read mostly applications

Simplified Dataguard broker parameter configurations

Observe only mode for data guard broker fast-satrt failover (FSFO)

Oracle dataguard multi-instance redo apply works with the in-memory column store

Finer granularity supplemental logging for logical standby databases

New Initialization Parameters in Oracle Database 19c 

"-optimizer_gather_stats_on_conventional_dml" and " _optimizer_use_stats_on_conventional_dml" which are true by default

-optimer_stats_on_conventional_dml_sample_rate(at 100%)

DATA_GUARD_MAX_IO_TIME

DATA_GUARD_MAX_LONGIO_TIME

MAX_DATAPUMP_JOBS_PER_PDB

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Flashback technology Recover a Dropped User in Oracle

Flashback technology  Recover a dropped user in oracle

Introduction

Using Flashback Technology  we can restore the dropped user in oracle we will flashback the database to past when the user is available at the time of dropped before,

Then take the export dump of the schema and restore the database to same current state once database is up we can import the dump file  

Prerequisites

1. Database must be Archivelog mode

2.Flash back must be enable for the database

3.All the flashback log and  Archive log should be available from the time the user is dropped 

Let us start the process

1.Make sure flashback and archive mode is enable.

SQL> select flashback_on,log_mode from v$database;

 

FLASHBACK_ON       LOG_MODE

------------------ -------------------------------

YES                                 ARCHIVELOG

2. lets drop the user and test the scenarios

04:47:15 SQL> select table_name from Chaitu_table where owner='CHAITANYA';

 

TABLE_NAME

----------------------------------------------------------------------------

ACCTTABLE1

MASTERTABLE2

 

 

04:47:33 SQL> drop user CHAITANYA cascade;

 

User dropped.

3.Flashback the database past when the user was available at that time

04:52:15 SQL> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

04:52:50 SQL> startup mount;

ORACLE instance started.

 

Total System Global Area 1.1107E+10 bytes

Fixed Size                  7644464 bytes

Variable Size            9294584528 bytes

Database Buffers         1711276032 bytes

Redo Buffers               93011968 bytes

Database mounted.

 

04:53:08 SQL> flashback database to timestamp to_date('20-AUG-2020 04:47:33','DD-MON-YYYY HH24:MI:SS');

 

Flashback complete.

4. Open the database in readonly mode

04:55:13 SQL> ALTER DATABASE OPEN READ ONLY;

 

Database altered.

 

04:55:31 SQL>  select table_name from chaitu_tables where owner='CHAITANYA';

 

TABLE_NAME

--------------------------------------------------------------

ACCTTABLE1

MASTERTABLE2

we can see the tables are available now

5. Take export backup of the schema CHAITANYA

# exp owner=CHAITANYA file=chaitanya.dmp

 

Export: Release 12.1.0.2.0 - Production on Tue Aug 20 05:17:45 2020

 

Copyright (c) 1982, 2014, Oracle and/or its affiliates.  All rights reserved.

 

 

Username: / as sysdba

 

Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production

With the Partitioning, OLAP, Advanced Analytics, Real Application Testing

and Unified Auditing options

Export done in US7ASCII character set and AL16UTF16 NCHAR character set

server uses AL32UTF8 character set (possible charset conversion)

 

About to export specified users ...

. exporting pre-schema procedural objects and actions

. exporting foreign function library names for user CHAITANYA

. exporting PUBLIC type synonyms

. exporting private type synonyms

. exporting object type definitions for user CHAITANYA

About to export CHAITANYA's objects ...

. exporting database links

. exporting sequence numbers

. exporting cluster definitions

. about to export CHAITANYA's tables via Conventional Path ...

. . exporting table                           ACCTTABLE1     75341 rows exported

EXP-00091: Exporting questionable statistics.

. . exporting table                          MASTERTABLE2        44 rows exported

EXP-00091: Exporting questionable statistics.

. exporting synonyms

. exporting views

. exporting stored procedures

. exporting operators

. exporting referential integrity constraints

. exporting triggers

. exporting indextypes

. exporting bitmap, functional and extensible indexes

. exporting posttables actions

. exporting materialized views

. exporting snapshot logs

. exporting job queues

. exporting refresh groups and children

. exporting dimensions

. exporting post-schema procedural objects and actions

. exporting statistics

Export terminated successfully with warnings.

6. Now restore the database to current state

SQL> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup mount

ORACLE instance started.

 

Total System Global Area 1.1107E+10 bytes

Fixed Size                  7644464 bytes

Variable Size            9294584528 bytes

Database Buffers         1711276032 bytes

Redo Buffers               93011968 bytes

Database mounted.

 

SQL> recover database;

Media recovery complete.

 

SQL> alter database open;

 

Database altered.

7. create the empty user and import the dumpfile

SQL> create user chaitanya identified by chaitanya;

 

User created.

 

SQL> grant connect,resource to chaitanya;

 

Grant succeeded.

 

# imp file=chaitanya.dmp fromuser=CHAITANYA TOUSER=CHAITANYA

 

Import: Release 12.1.0.2.0 - Production on Tue Aug 20 05:23:59 2020

 

Copyright (c) 1982, 2014, Oracle and/or its affiliates.  All rights reserved.

 

Username: / as sysdba

 

Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production

With the Partitioning, OLAP, Advanced Analytics, Real Application Testing

and Unified Auditing options

 

Export file created by EXPORT:V12.01.00 via conventional path

import done in US7ASCII character set and AL16UTF16 NCHAR character set

import server uses AL32UTF8 character set (possible charset conversion)

. importing DBACLASS's objects into DBACLASS

. . importing table                        " ACCTTABLE1 "      75341 rows  imported

. . importing table                        "MASTERTABLE2"          44 rows imported

 we can restore the schema user chaitanya by using flashback technology

Note : Info on Flashback technology it may be differ in your environment like production,testing ,development and naming conventions 

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