Rename LOB Segments, partitions, sub partitions in Oracle 23ai

From Oracle 23ai, you can rename LOB (Large Object) segments, partitions and sub partitions using “ALTER TABLE RENAME LOG” statement. In previous versions of the database to rename LOB segment you need to move it using “ALTER TABLE MOVE” statement.

When renaming a segment make sure the segment is unique within the database, in case of any conflicts you will receive ORA-64233 or ORA-63223 error messages. To make sure segment available in the database you can query ALL_LOBS, ALL_PARTITIONS, ALL_LOG_SUBPARTITIONS.

You can use below syntax/example to rename LOB segment

ALTER TABLE <TABLE_NAME> RENAME LOB (<column_name>) <segment_name> to <new_segment_name>;

SQL> SELECT TABLE_NAME, COLUMN_NAME, SEGMENT_NAME FROM USER_LOBS WHERE TABLE_NAME = 'LOB_TAB1’;

TABLE_NAME COLUMN_NAME SEGMENT_NAME
-------------------- ----------------------- -------------------------
LOB_TAB1        LOB_COL1            LOB_SEG1

SQL> ALTER TABLE lob_tab1 RENAME LOB (lob_col1) log_seg1 TO log_seg1_new;

SQL> SELECT TABLE_NAME, COLUMN_NAME, SEGMENT_NAME FROM USER_LOBS WHERE TABLE_NAME = 'LOB_TAB1’;

TABLE_NAME COLUMN_NAME SEGMENT_NAME
-------------------- ----------------------- --------------------
LOB_TAB1        LOB_COL1            LOB_SEG1_NEW


You can also rename partition, sub partition segments using below examples

For Partition,
ALTER TABLE lob_tab2 RENAME LOB(lob_col2) PARTITION lob_seg2 TO lob_seg2_new;

For Sub partition,
ALTER TABLE lob_tab3 RENAME LOB(LOB_COL3) SUBPARTITION lob_seg3 TO lob_seg3_new;

The new capabilities simplify the management of LOBs, partitions by reducing the overhead in the Oracle Database.

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Webinar: Unlocking Oracle Database 23c’s Advanced Security Features

 Join this webinar to learn about Oracle Database 23c's most recent security improvements. We'll go over new features including enhanced authentication techniques and encryption, demonstrating how they help safeguard your data and bolster security against changing threats. This webinar is Ideal for database administrators and IT specialists wishing to increase database security.

Date and time: Dec 13th 2024, 8:00am-9:00am
Pacific Daylight Time (San Francisco, GMT-07:00)

This Webinar covers following Topics.

• SQL Firewall
• Audit
• Authentication
• Authorization
• Encryption
• Autonomous Database
• Other

To register for this Webinar, please send an email to SatishbabuGunukula@gmail.com
Here is the Webinar Meeting Link

Click here to view the Presentation

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ORA-04031: unable to allocate 12312 bytes of shared memory ("shared pool","unknown object","KKSSP^212","kglseshtTable")

We recently encountered the following error in 19c, which typically occurs when the database needs additional shared memory. In most of the cases setting MAX_SGA_SIZE to a higher value will resolve the issue.

Below are some possible cause

•  Insufficient memory allocated via initialization parameters
•  Fragmentation in app design
•  Auto tuning issues
•  A Bug causing the issue
•  Memory leaks

ORA-04031: unable to allocate 12312 bytes of shared memory ("shared pool","unknown object","KKSSP^334","kglseshtTable")
< ORA-00604: error occurred at recursive SQL level 1 < ORA-04031: unable to allocate 40 bytes of shared memory ("shared pool","unknown object","KGLH0^f185eace","kglHeapInitialize:temp")
< ORA-04031: unable to allocate 12312 bytes of shared memory ("shared pool","unknown object","KKSSP^394","kglseshtTable")


The error message will provide the amount of memory unavailable, memory pool facing the issue and failed allocation details

 

I would highly suggest running below query to get the optimal value for SGA_TARGET
Select * from V$SGA_TARGET_ADVICE

Note that in order to initialization parameters to take into effect we need to bounce the instance.

AGLT>oerr ora 04031
04031, 00000, "unable to allocate %s bytes of shared memory (\"%s\",\"%s\",\"%s\",\"%s\")"
// *Cause: More shared memory is needed than was allocated in the shared
// pool or Streams pool.
// *Action: If the shared pool is out of memory, either use the
// DBMS_SHARED_POOL package to pin large packages,
// reduce your use of shared memory, or increase the amount of
// available shared memory by increasing the value of the
// initialization parameters SHARED_POOL_RESERVED_SIZE and
// SHARED_POOL_SIZE.
// If the large pool is out of memory, increase the initialization
// parameter LARGE_POOL_SIZE.
// If the error is issued from an Oracle Streams or XStream process,
// increase the initialization parameter STREAMS_POOL_SIZE or increase
// the capture or apply parameter MAX_SGA_SIZE.
// parameter MAX_SGA_SIZE.

Refer below links for Oracle support notes

• This Oracle support note provides information about ORA-04031 related bugs and which release they were fixed

OERR: ORA-4031 "unable to allocate %s bytes of shared memory ("%s","%s","%s")" (Doc ID 4031.1)

• This Oracle note provides detailed troubleshooting and diagnosing details

Troubleshooting and Diagnosing ORA-4031 Error [Video] (Doc ID 396940.1)

• This Oracle note provides detailed understanding and tuning of the of the shared pool

NOTE:62143.1 - Troubleshooting: Understanding and Tuning the Shared Pool

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Annotations in Oracle 23ai

Oracle Database23ai introduced new feature annotations, using this feature user can add additional comments to objects and allow storing database object metadata. It helps to share the metadata across applications.

You can add annotations to any supported schema objects with CREATE privilege and you can add or drop annotations using ALTER privilege, the object can have more than one annotation as well. The supported schema objects include tables, indexes, views, materialized views. An annotation will consist of a name and an optional value, which can be entered as freeform text fields.

You can drop the annotations, or it will be dropped when a schema object is dropped. You can query USER|ALL|DBA_ANNOTATIONS_USAGE to view annotations for an object.

Annotation has three clauses i.e ADD, DROP or REPLACE

ADD – create annotations for an existing object.
DROP – removes the annotation from an object.
REPLACE – change annotation_value. This clause used with ALTER statements.

In below example, we’re adding annotation both table and columns

CREATE TABLE emp (
emp_id number ANNOTATIONS (ColumnInfo ‘Employee ID’),
emp_name varchar2(30) ANNOTATIONS (ColumInfo ‘Employee Name’),
dept varchar2(20) )
ANNOTATIONS ( TableInfo ‘Employee Table’);

SQL> SELECT ANNOTATION_NAME, ANNOTATION_VALUE from USER_ANNOTATIONS_USAGE WHERE Object_Name ='EMP' AND Object_Type = 'TABLE' AND Column_Name IS NULL;

ANNOTATION_NAME ANNOTATION_VALUE
-------------------- --------------------
TABLEINFO Employee Table

You can drop annotation from an existing table using below example
SQL> ALTER TABLE emp ANNOTATIONS (DROP TableInfo);

You can add annotation to the table using below example, note that ADD keyword is optional.
SQL> ALTER TABLE emp ANNOTATIONS (ADD TableInfo ‘Employee Table’);

SQL> SELECT ANNOTATION_NAME, ANNOTATION_VALUE from USER_ANNOTATIONS_USAGE WHERE Object_Name ='EMP' AND Object_Type = 'TABLE' AND Column_Name IS NOT NULL;

ANNOTATION_NAME ANNOTATION_VALUE
-------------------- --------------------
EMP_ID Employee ID
EMP_NAME Employee Name

In below example you can add, replace and drop annotations at column level. Note that ADD keyword is optional.

SQL> ALTER TABLE EMP modify dept ANNOTATIONS (ADD ColumnInfo ‘Dept Name’);
SQL> ALTER TABLE EMP modify dept ANNOTATIONS (REPLACE ColumnInfo ‘Deptartment Name’);
SQL> ALTER TABLE EMP modify dept ANNOTATIONS (DROP ColumnInfo);

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Authentication enhancements in Oracle 23c

Oracle 23c offers longer passwords improved security in authentication now supports up to 1024 bytes

• Oracle Data pump Export and import support longer encryption passwords up to 2024 bytes long

• Oracle Call interface (OCI) and Oracle C++ Call interface support up to 1024 bytes long password for user authentication.
• JDBC think driver support up to 1024 characters for password
• Oracle Database (including Autonomous) and clients supports password up to 1024 bytes

You can login into Oracle Database using Microsoft Azure Active Directory single sing-on OAuth2 access token. Multicloud feature integrates Oracle Database and Azure AD and you can perform this integration on

• Oracle 19.16 and later (Back ported) but not for Oracle 21c.
• Oracle Autonomous Database on Dedicated/Shared Exadata Infrastructure
• Oracle Exadata Clod Service
• Oracle Base Database Service

You can map AD users to Oracle Database schema and roles and also you can login ODP.NET can login into Oracle Database Using Microsoft Azure Active Directory. The UTL_HTTP support SHA-256/512 and XDB HTTP supports SHA512, authentication and updated Kerberos Library support.

The password length helps accommodating Oracle Identity Access management (IAM) and Identity Cloud service (IDCS) and helps enabling uniform password rules.

Oracle 23c offers many Improvements in Kerberos security and MIT Kerberos version 1.20.1 supports cross domain, windows credential guard and multiple principals.

KERBEROS5_CC_NAME and KERBEROS5_PRINCIPAL can be specified in tnsnames.ora and the values must match for user authentication.

kuser =
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=orahost)(PORT=1521)) (CONNECT_DATA=(SERVICE_NAME=ORCL))
(SECURITY=(KERBEROS5_CC_NAME = /tmp/kuser/krb.cc) (KERBEROS5_PRINCIPAL = kprinc)))

Kerberos parameters can be specified in Sqlnet.ora file but note that some parameters you can set at server level, and some are at client level and few you can set on both.

You can set below parameters on both client and server

SQLNET.AUTHENTICATION_SERVICES=(KERBEROS5)

SQLNET.AUTHENTICATION_KERBEROS5_SERVICE=oracle

SQLNET.KERBEROS5_CONF=<Kerberos_configfile_path >

SQLNET.KERBEROS5_CONF_MIT=(TRUE)

SQLNET.FALLBACK_AUTHENTICATION=FALSE

SQLNET.KERBEROS5_CLOCKSKEW=1200

The below parameter is not required on the server, but in case if your client in Microsoft Windows then you may want to consider setting OSMSFT:// or MSLSA

SQLNET.KERBEROS5_CC_NAME= <Kerberos_CC_name_withpath>

This setting is not usually required for the client or the server.

SQLNET.KERBEROS5_REALMS=<Kerberos_realms_path >

Only set this parameter on the server

SQLNET.KERBEROS5_KEYTAB=<Kerberos_keytab_path > 

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