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Introduction A Refreshable Clone PDB is a special type of Pluggable Database introduced in Oracle Database 12.2 that allows you to periodically synchronize a cloned PDB with its source by applying redo data. In this article, we will configure the Refreshable Clone PDB. Refresh Mode Automatic Refresh Mode: the clone is automatically synchronized with its source PDB at fixed, predefined time intervals. The refresh occurs based on the interval specified in the REFRESH MODE EVERY n MINUTES clause during creation or modification of the clone. Manual Refresh Mode: synchronization with the source PDB occurs only when explicitly initiated by the DBA. The clone is created using the REFRESH MODE MANUAL clause and refreshed on demand using the ALTER PLUGGABLE DATABASE pdb_name REFRESH command. Note: the refreshable clone PDB must be closed (mount state) during the refresh process. It cannot be open, not even in read-only mode. This applies regardless of refresh mode. Prerequisi...

Introduction An Oracle Logical Standby database can be used for write operations if required, to run reports or test statements. However, if the same transaction is executed on the primary, it will create a conflict and SQL Apply will abort on the standby, resulting in the primary and standby falling out of sync. In this article, we will see how to resolve such an issue by skipping the transaction. Prerequisites Logical standby should be configured and in sync. Environment Used in this Guide Server Primary Standby Hostname drdb.oraeasy.com dcdb.oraeasy.com OS OEL 9 OEL 9 SID ORADBDR ORADBDC Service Name ORADBDR ORADBDC Creating and Resolving the Conflict Step by Step Step 1: Check the Sync Between Primary and Standby Before intentionally creating a conflict, confirm the standby is fully in sync. This ...

Introduction AWR (Automatic Workload Repository) is an Oracle performance monitoring feature that collects, processes, and stores database performance statistics. These statistics are used for problem diagnosis and self-tuning of the database. The collected data can be viewed through database views or generated as HTML or text reports, helping DBAs analyze the current performance state of the database in detail. Background Processes for AWR MMON : collects AWR statistics. MMNL : writes ASH and AWR data to disk. Data Collected by AWR AWR captures a wide range of performance-related metrics, including: Object statistics: access and usage statistics of database segments. Time model statistics: data from the V$SYS_TIME_MODEL and V$SESS_TIME_MODEL views. System and session statistics: selected statistics from the V$SYSSTAT and V$SESSTAT views. Active Session History (ASH) statistics. High-load SQL statements contributing significantly to database workload. Prerequ...

Introduction A switchover is a role reversal between the primary database and one of its standby databases. In this article we will see how to perform a switchover activity in a Logical Standby setup. Prerequisites Logical standby should be configured and in sync. 30 mins downtime at database end. Environment Used in this Guide Server Primary Standby Hostname dcdb.oraeasy.com drdb.oraeasy.com OS OEL 9 OEL 9 SID ORADBDC ORADBDR Service Name ORADBDC ORADBDR Switchover Activity Step by Step Step 1: Check the Sync Between Primary and Standby Confirm the logical standby is fully caught up before starting a switchover. Attempting one against a lagging standby risks data loss or an extended outage. Primary: SQL> select name,db_unique_name,database_role,open_mode from v$database; NAME DB_UNIQUE_...