Oracle AI Database 26ai: Redefining Operational Continuity

Oracle’s latest release, AI Database 26ai, is built around one clear promise: making enterprise database operations faster, more resilient, and easier to manage at scale. Instead of spotlighting a single headline feature, the release emphasizes a collection of practical improvements that together transform how production systems are maintained and kept online.

Key Highlights

• Fast start reconfiguration — adapts quickly to infrastructure changes.

• Fast pluggable database open — accelerates availability in multitenant setups.

• Rolling maintenance — single‑server and local rolling updates minimize disruption.

• RAC two‑stage rolling update — staged upgrades reduce operational risk.

• Smart connection rebalancing — smooth workload redistribution during topology changes.

• Faster role transitions — critical for disaster recovery and failover.

• Pluggable database recovery isolation — stronger fault containment in multitenant environments.

• Data Guard with PL/SQL — automation‑friendly administration.

• DBMS rolling upgrades — upgrades without user impact.

• Online patching support — shorter maintenance windows.

• RAFT‑based replication — stronger distributed architecture.

• Flashback time travel — enhanced recovery and historical analysis.

Why It Matters

1. Availability during change Rolling upgrades, online patching, and maintenance with minimal downtime ensure systems remain accessible even during operational work.

2. Isolation in multitenant environments Recovery and protection can now be applied at the pluggable database level, reducing the blast radius of failures.

3. Distributed resilience RAFT‑based replication and sharding enable global applications to maintain consistency and availability across geographies.

The Bigger Picture

Oracle AI Database 26ai is not just about adding intelligence—it’s about continuous operation. The release reflects a shift in database philosophy: platforms are expected to stay online while being patched, upgraded, rebalanced, and recovered.

For database administrators, platform engineers, and architects, this means:

• fewer disruptive maintenance events,

• faster recovery paths,

• smoother failover orchestration,

• stronger distributed behavior,

• and uninterrupted application continuity.

Final Thought: Oracle AI Database 26ai positions itself as a platform for operational simplicity and resilience. The future of enterprise databases lies not only in intelligence but in uninterrupted operation.

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Oracle Patching Process and Commands

Keeping Oracle database software up to date is crucial for maintaining system security, stability, and performance of the database. Below, we will see a structured approach to patching Oracle environments using OPatch, Oracle’s patching utility. Let’s break down the process and commands in detail.

Types of Oracle Patches

Patch Type	Description	Typical Use
One-Off Patch	Fixes a single issue	Urgent bug fix
PSU (Patch Set Update)	Security and bug fixes	Regular maintenance
RU (Release Update)	Security, bug, and functional fixes	Broader updates
RUR (Release Update Revision)	Smaller revision of RU	Minor improvements

 

Follow these steps for a smooth and safe patching experience in production environments:

1 .Check Current Version

SELECT * FROM v$version;

Confirms the current Oracle version before applying any patch

 

2. Plan & Take Backup

Use RMAN for database backup and copy the Oracle Home directory.

 

3. Pre-Patch Checks

Verify patch readiness, available space, and potential conflicts.

 

4. Stop Services 

Shutdown Database, Listener, and ASM if required to prevent conflicts.

 

5. Apply Patch

opatch apply

 

6. Run Datapatch

datapatch -verbose

Updates the database dictionary and applies SQL changes.

7. Start Services

Start the services, such as the database, listener, or ASM.

 

8. Verify Patch

opatch lsinventory

SELECT * FROM dba_registry_sqlpatch;

 

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Table Dropped in Oracle Database ? Worry not, we can recover it

There are a couple of options we can use to recover dropped tables in 19c Oracle database version 

Restore table from Recycle Bin (assume not purged)

To recover the table using the recycle bin method, the recycle bin should be enabled 

Check current value 

SHOW PARAMETER recyclebin;

If this is not enabled, enable it using commands below

ALTER SYSTEM SET recyclebin = ON SCOPE=SPFILE;

 

Shutdown immediate

startup

 

drop table techno_user.test_table;

Check if table exists in recyclebin after drop 

col owner for a20

col owner for a15

col object_name for a30

col ORIGINAL_NAME for a10

set line 120

SELECT owner, object_name, original_name, type, droptime

FROM dba_recyclebin WHERE original_name = 'TEST_TABLE' and owner='TECHNO_USER' ;

 

OWNER           OBJECT_NAME                    ORIGINAL_N TYPE                      DROPTIME

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

TECHNO_USER     BIN$JtPeMal0R/Wwtmwyqoos3g==$0 TEST_TABLE TABLE                     2026-01-11:11:06:16

Check if you want to recover only a row or a table

SELECT * FROM techno_user."BIN$JtPeMal0R/Wwtmwyqoos3g==$0";

Restore it to either original value or you can rename it while restoring 

SQL> FLASHBACK TABLE techno_user.test_table TO BEFORE DROP;

Flashback complete.

SQL> FLASHBACK TABLE techno_user.test_table TO BEFORE DROP RENAME TO TEST_TABLE_BKP ;

Flashback complete.

 

 

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PostgreSQL : Tablespaces

PostgreSQL stores all the data under its data directory(PGDATA), but that does not mean that data cannot be stored outside the data directory. Most of the database administrators make use of the default tablespace and overlook the powerful features of tablespaces. 

Meaning of tablespace in Postgres

A tablespace in PostgreSQL is simply a location on disk where the database can store data files. By default, PostgreSQL stores all data inside the PGDATA directory. However, in real-world scenarios, you might want to spread data across multiple storage devices or different drives or folders to better performance

• Performance – by distributing I/O load across different storage devices
• Scalability – by placing large tables or indexes on faster storage disks.
• Storage Management – by using cheaper storage for less critical data and high-performance SSDs for frequently accessed data.

Command to check tablespaces in PostgreSQL

\db or \db+

Creating a new tablespace (user-defined)

 

postgres=# CREATE TABLESPACE technodb LOCATION 'C:\Program Files\PostgreSQL\pg_technodb';

CREATE TABLESPACE

postgres=# \db+

                          List of tablespaces

  Name    |  Owner   |Location           | Access privileges | Options |  Size   | Description

------------+----------+----------------+-------------------+---------+---------+--

 pg_default | postgres |                 |                   |         | 29 MB   |

 pg_global  | postgres |                 |                   |         | 534 kB  |

 technodb   | postgres | C:\Program Files\PostgreSQL\pg_technodb |     | 0 bytes |

(3 rows)

 

postgres=# 

 

To create a tablespace, a physical directory should be present before creating the tablespace.

we can assign tablespaces to individual databases, tables, or indexes. 

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Oracle Active Data Guard Features and Benefits

Oracle Active Data Guard enhances the performance of production databases by offloading resource-consuming operations to one or more standby databases. This protects interactive users and critical business tasks from the impact of long-running operations. 

Active Data Guard enables a physical standby database to be used for real-time reporting with minimal latency. Compared to traditional replication methods, it is simple to use and has very good performance.

Oracle Active Data Guard enables read-only access to a physical standby database for queries, sorting, reporting, web-based access, etc., while continuously applying changes or archived logs received from the production database.

Active Data Guard also enables fast incremental backups when offloading backups to a standby database, and can provide additional benefits of high availability and disaster protection against planned or unplanned outages at the production site.

Features

• Physical Standby with Real-Time Query
• Fast Incremental Backup on Physical Standby

Benefits

• Increase performance– Offload unpredictable workloads to an up-to-date replica of the production database
• Simplify operations– Eliminate management complexity that accompanies traditional replication solutions
• Eliminate compromise– The reporting replica is up to date and online at all times, which is not possible with traditional storage mirroring technology
• Reduce cost– An Oracle Active Data Guard physical standby database can also provide disaster recovery and/or serve as a test database – no additional storage or servers required
• Enables a standby database for use in real-time for reporting
• Offloads backup operations
• Insulates critical operations from unexpected system impacts
• Provides high availability and disaster protection

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Oracle 23ai : The all new Hybrid Read-Only for pluggable databases (PDBs)

 

The latest Oracle database version, Oracle 23ai, introduced a new open mode called Hybrid Read-Only for pluggable databases (PDBs). Local users can only connect with read-only access when a PDB is set to this new mode. However, common users are not restricted and can still perform write operations.

Command to convert to this mode

SQL> ALTER PLUGGABLE DATABASE TECHNOPDB OPEN HYBRID READ ONLY;
Pluggable database altered.

SQL> show pdbs;
    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 TECHNOPDB                      READ WRITE NO

Testing Write Access with common user - SYS

Now, we connect to TECHNOPDB as the SYS user and test write operations:

sqlplus "sys/sys@target:1521/TECHNOPDB as sysdba"

SQL> show user;
USER is "SYS"

SQL> select OPEN_MODE from v$pdbs;
OPEN_MODE
----------
READ WRITE

SQL> create table tech_user.test_tab(id number);
Table created.

As we can see, the SYS user sees the OPEN_MODE as READ WRITE, even though the PDB was opened in HYBRID READ ONLY mode.

Testing Write Access as any Local User

Now, let us repeat the test with a local user named VAHID:

sqlplus "tech_local/test123@target:1521/TECHNOPDB"

SQL> show user;
USER is "tech_local"

SQL> select OPEN_MODE from v$pdbs;
OPEN_MODE
----------
READ ONLY

SQL> create table tech_user.test_tab(id number);
ORA-16000: Attempting to modify database or pluggable database that is open for read-only access.

As expected, the local user (TECH_LOCAL) is not allowed to perform write operations.

Checking Hybrid Read-Only Mode Status

The view V$CONTAINER_TOPOLOGY can help to check the HYBRID READ ONLY mode:

SQL> select IS_HYBRID_READ_ONLY, CON_NAME, OPEN_MODE from V$CONTAINER_TOPOLOGY;

IS_HYBRID_READ_ONLY  CON_NAME   OPEN_MODE
-------------------- ---------- ----------
YES                  ORCLORPDB  READ WRITE

 

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Oracle Dataguard Broker Configuration (DGMGRL)

Data Guard Broker is a command-line interface that makes managing primary and standby databases easy. DBA can use a single command to switch from primary and standby and vice versa.

Several pre-defined commands can be used to manage Data Guard. Data guard configuration is one of the steps in the primary and standby database setup.

 

The steps below will describe the configuration and other uses

 

Step 1: Add the configuration file to both the databases (primary/standby)

 

Configuration files save the status of the primary and standby database

 

SQL> show parameter DG_BROKER_START

 

NAME                                 TYPE        VALUE

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

dg_broker_start                      boolean     TRUE

 

SQL> ALTER SYSTEM SET DG_BROKER_START=FALSE;

 

System altered.

 

SQL> alter system set dg_broker_config_file1='/u01/oracle/prim_db/dguard/dg1_prim_db.cfg' scope=both;

 

System altered.

 

SQL> alter system set dg_broker_config_file2='/u01/oracle/prim_db/dguard/dg2_prim_db.cfg' scope=both;

 

System altered.

 

Perform similar steps on the Standby side as well

 

Step 2: Set up of DG_BROKER_START parameter on the primary and standby databases

 

SQL> ALTER SYSTEM SET DG_BROKER_START=TRUE SCOPE=BOTH;

 

System altered.

 

SQL> show parameter DG_BROKER_START

 

NAME                                 TYPE        VALUE

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

dg_broker_start                      boolean     TRUE

 

Step 3: Set up local listener parameters on the primary and the standby.

 

Primary-> alter system set local_listener='(ADDRESS = (PROTOCOL = TCP)(HOST =prim_server.pfizer.com)(PORT = 1522))' scope=both;

 

Standby-> alter system set local_listener='(ADDRESS = (PROTOCOL = TCP)(HOST =standby_server.pfizer.com)(PORT = 1522))' scope=both;

 

Step 4: DGMGRL configuration

 

Connect to primary db through dgmgrl

 

prim_server.pfizer.com-prim_db $ dgmgrl /

DGMGRL for Linux: Release 19.20.0.0.0 - Production on Wed Apr 09 04:52:13 2025

 

Copyright (c) 1982, 2023, Oracle and/or its affiliates.  All rights reserved.

 

Welcome to DGMGRL, type "help" for information.

Connected to "prim_db"

Connected as SYSDG.

DGMGRL> create configuration prim_db_conf as Primary Database is 'prim_db' connect identifier is prim_db.pfizer.com;

Configuration "prim_db_conf" created with primary database "prim_db"

DGMGRL>

DGMGRL> ADD DATABASE 'standby_db' AS CONNECT IDENTIFIER IS standby_db.pfizer.com MAINTAINED AS PHYSICAL;

Database "standby_db" added

DGMGRL>

DGMGRL> enable configuration;

Enabled.

DGMGRL> show configuration;

 

Configuration - prim_db_conf

 

  Protection Mode: MaxPerformance

  Members:

  prim_db - Primary database

  standby_db - Physical standby database

 

Fast-Start Failover: DISABLED

 

Configuration Status:

SUCCESS   (status updated 4 seconds ago)

 

Output should be SUCCESS; if not, we need to rectify the issues.

 

 

Step 5:  Monitor and manage and Data Guard Broker configuration

 

Check configuration status:

DGMGRL> show configuration;

 

Check configuration details of each database

DGMGRL> show database 'prim_db';

DGMGRL> show database 'standby_db';

 

Enable or Disable configuration for individual database

DGMGRL> enable database 'prim_db';

DGMGRL> disable database 'standby_db';

 

Useful Commands in DGMGRL

 

CREATE CONFIGURATION

ADD DATABASE

EDIT DATABASE

SHOW DATABASE

ENABLE CONFIGURATION

SWITCHOVER TO

FAILOVER TO

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