ANIL VEJENDLA

  In the modern security landscape, Transparent Data Encryption (TDE) is no longer optional, it is a fundamental requirement for protecting data at rest. While the ALTER TABLESPACE command seems straightforward, the underlying mechanics of how Oracle handles online encryption especially in environments with Data Guard can be surprising. Recently, I’ve been exploring the nuances of online TDE operations. Here are the key takeaways and "gotchas" every DBA should know before hitting 'enter' on that encryption command. 1. The Power of Online Encryption Oracle allows you to encrypt an existing unencrypted tablespace while the database is open and being accessed by users. The syntax is simple: SQL ALTER TABLESPACE TEST ENCRYPTION ONLINE ENCRYPT; Pro Tip: In Oracle 19c, the default algorithm is AES128. If your security standards require AES256, you should set the parameter tablespace_encryption_default_algorithm to 'AES256' or specify it explicitly in yo...

  In an era where data is the new oil, your database is the high-security vault. But how often do you check the locks? For Oracle Database users, the Database Security Assessment Tool (DBSAT) is the essential "home inspection" kit for your data environment. Whether you're preparing for a GDPR audit or just trying to sleep better at night, DBSAT provides a fast, comprehensive way to evaluate your security posture. What is DBSAT? Oracle DBSAT is a lightweight, command-line utility that identifies security risks by analyzing database configurations, user entitlements, and sensitive data locations. It doesn’t just point out problems; it provides actionable recommendations based on CIS Benchmarks , DISA STIG , and Oracle best practices. The Three Pillars of DBSAT The tool operates through three distinct components: The Collector: Runs SQL queries and OS commands on the database server to gather raw metadata. The Reporter: Analyzes the collecte...

 In the fast-paced world of database administration and development, the pressure to get things done often collides with the need for security. How many times have you, as a DBA, succumbed to the temptation of granting SELECT ANY TABLE or DBA privileges to a developer just to bypass a perplexing ORA-00942: table or view does not exist error? We’ve all been there. It’s the "Get it Working Now, Fix it Later" approach. The problem is, "later" rarely comes, and your database becomes a Swiss cheese of excessive permissions. This is the anti-pattern of the Principle of Least Privilege (PoLP) , which dictates that a user should only have the privileges necessary to perform their specific job - no more, no less. Over-privileged users are a massive security risk, turning a single compromised account into a database-wide breach. Oracle Database 23ai changes the game. With its focus on "Security by Design," 23ai introduces features that make implementing least pri...

  What is Oracle ARS? ARS is a fully managed backup and recovery service based on the proven Zero Data Loss Recovery Appliance (ZDLRA) technology. Problem: Traditional backups can lead to data loss between scheduled intervals (RPO) and slow recovery times (RTO). Solution: ARS offers real-time transaction protection, reducing RPO to less than one second . Key Benefits (Why ARS is recommended?) Zero Data Loss: Real-time redo transport ensures even the most recent transactions are protected. Incremental Forever Strategy: Only changes are backed up after the initial full backup, reducing database overhead and network traffic. Backup Immutability: Includes a retention lock feature to protect against ransomware and accidental deletion. Cloud Simplicity: Integrated directly into the OCI Console for "one-click" enablement Prerequisites : The minimum supported Oracle Database versions for using ARS within the Or...

                                                    ADG_REDIRECT_DML Introduction Historically, Active Data Guard (ADG) was strictly read-only. If an application needed to perform even a tiny "Insert into Audit_Log," it had to connect to the Primary. The  DML Redirection  feature marks a significant shift in ADG capabilities.  ADG_REDIRECT_DML allows the standby to accept DML, transparently redirect it to the Primary, and wait for the apply service to bring the change back. This functionality effectively eliminates the 'look-but-don't-touch' limitation, providing a seamless experience for read-mostly applications that require occasional data persistence. Prerequisites & Environment Oracle Database Version: 19c or higher. License: Active Data Guard option. Mode: Standby must be in READ ONLY WITH APPLY (Active Data Guard). Primary Databa...

Unable to connect to PDB  as a system in Oracle 12.2 Issue :  When we are trying to connect as system user it is hanging forever and not allowing new connections. (No issues observed with existing application connections) Error: Errors in alert log file Errors in file /u01/app/oracle/diag/rdbms/XXXXX/XXXXX/trace/xxxxx_ora_127384.trc: ORA-04088: error during execution of trigger 'SYS.BLOCK_TOOLS_FROM_PROD' ORA-00604: error occurred at recursive SQL level 1 ORA-20000: Development tools are not allowed here. ORA-06512: at line 13 2020-06-10 12:31:44.388000 +00:00 WARNING: CLMN has failed to cleanup a dead process for 2400 attempts 2020-06-10 08:38:11.555000 +00:00 WARNING: CLMN has failed to cleanup a dead process for 1000 attempts Errors in file /u01/app/oracle/diag/rdbms/xxxxx/xxxxx/trace/xxxxx_clmn_114254.trc  (incident=8918402) (PDBNAME=CDB$ROOT): ORA-00700: soft internal error, arguments: [ksuxdl: cleanup failures], [0x351C23FC0...