Oracle Internals

Networking is one of the most important foundations of any cloud deployment, and in Oracle Cloud Infrastructure (OCI), this foundation is built using a Virtual Cloud Network (VCN) . Whether you are deploying Oracle Databases, application servers, Kubernetes clusters, or enterprise workloads in OCI, understanding how VCN works is essential for building secure, scalable, and highly available architectures. In this article, we will explore the basics of VCN, its major components, and some best practices for designing OCI networks. What is a VCN? A Virtual Cloud Network (VCN) in OCI is a private virtual network that you create inside Oracle Cloud. It works very similarly to a traditional data center network, but without requiring physical hardware. A VCN gives you complete control over: IP address ranges Subnets Routing Security rules Internet connectivity Hybrid cloud connectivity Each VCN is logically isolated from other customer networks within OCI, ensuring security and s...

 Oracle Enterprise Manager (OEM) provides the Gold Image feature to simplify large-scale agent management and standardization. Using Gold Images, administrators can maintain a consistent agent configuration, plugin set, and patch level across multiple servers. This feature is available in OEM 13c and was also present in earlier OEM releases with similar functionality. In this article, we will walk through the process of creating, managing, and deploying a Gold Agent Image using emcli . Why Use Gold Images? Gold Images help standardize OEM agents across environments by allowing administrators to: Maintain consistent plugin versions Simplify agent patching and upgrades Reduce manual configuration drift Automate large-scale agent deployments Ensure uniform monitoring behavior Instead of patching every agent individually, administrators can prepare one reference agent and use it as the baseline for all other agents. Step 1: Login to EMCLI and Synchronize Before per...

 The Event Monitor process, commonly known as EMON , is primarily responsible for handling notifications inside the Oracle Database. One of its major use cases is supporting Database Change Notification (DCN) , where applications subscribe to database objects and receive notifications whenever changes occur. Applications often rely on these notifications to trigger downstream actions automatically. In most environments, this works seamlessly in the background. However, there are situations where EMON-related waits can become a serious performance concern. What is EMON Doing Internally? EMON works closely with Oracle Advanced Queuing (AQ). Whenever database changes occur on subscribed objects, notifications are placed into internal queues. EMON then processes these notifications and sends callbacks to the subscribed clients. Since EMON is an Oracle background process, database administrators generally do not have direct operational control over it. Oracle automatically spawns an...

 Tracing is one of the most powerful techniques available in Oracle Database for diagnosing SQL performance issues, wait events, execution behavior, and session activity. The 10046 trace event is commonly used to collect detailed SQL trace information, including: SQL execution statistics Wait events Bind variables Execution timings This article covers multiple ways to enable 10046 tracing in Oracle Database. 1. Session Level Tracing Use this method when you want to trace only the current database session. ALTER SESSION SET tracefile_identifier = '10046' ; ALTER SESSION SET timed_statistics = TRUE ; ALTER SESSION SET statistics_level = ALL ; ALTER SESSION SET max_dump_file_size = UNLIMITED; ALTER SESSION SET events '10046 trace name context forever, level 12' ; Now execute the SQL statements or operations you want to trace: SELECT * FROM dual; Disable tracing after completing the test: ALTER SESSION SET events '10046 trace...