Oracle Performance Insights A Blog By Kamlesh Ambre

  Introduction Oracle Database 23ai introduced a powerful new diagnostic capability through the DBMS_SQLDIAG.REPORT_SQL function, which generates comprehensive HTML diagnostic reports for SQL statements. The great news for Oracle 19c users is that this feature has been backported to Oracle Database 19.28 , allowing you to leverage advanced SQL analysis without upgrading to 23ai. Before this feature, DBAs typically relied on the awrsqrpt.sql script to analyze SQL execution plans and performance metrics. The new REPORT_SQL function provides a more comprehensive, graphical HTML report with deeper performance insights. What Does SQL Diagnostic Report Provide? The REPORT_SQL function generates a comprehensive HTML diagnostic report that includes: Execution Plan History - Track how execution plans have evolved over time Cursor Sharing Information - Understand cursor behavior and sharing patterns Optimizer Statistics History - View changes in optimizer statistics Index ...

In large-scale enterprise environments, managing databases and their infrastructure can quickly become a time-consuming and error-prone process — especially when done manually. Oracle Enterprise Manager (OEM) already provides a strong foundation for monitoring databases, operating systems, WebLogic servers, and more. But its real strength unfolds when combined with Database Lifecycle Management (DBLM) — a powerful extension that brings automation, compliance, and control to your database environment.   In this blog, we’ll explore why adopting DBLM features is a strategic move for organizations looking to boost operational efficiency, minimize risks, and reduce human intervention.     🌟  Why DBLM?   Database Lifecycle Management (DBLM) is an advanced management pack that enhances OEM by automating critical aspects of database operations, enabling IT teams to focus on strategic initiatives rather than repetitive maintenance tasks.   Here are the key features...

Recently, one of our valued customers experienced a significant downtime event when their complete 6-node RAC cluster fell into a hang state due to a massive pile-up of sessions, exceeding 6000. The gravity of the situation was immediately apparent as the downtime persisted intermittently for nearly four hours, from 2:10 PM to 5:30 PM, impacting critical transactions and leading to declines. Upon their reaching out to us for assistance, our troubleshooting journey commenced, aiming to uncover the root cause and provide recommendations to rectify the issue. Problem Statement: The 6-node cluster entered a hang state despite attempted reboots, resulting in a prolonged outage with severe implications for transaction processing. Unraveling the Culprit: The issue presented itself as a perplexing anomaly, requiring thorough analysis of diagnostic data within the live system. Initial investigations revealed a high occurrence of GC and logfile sync wait events amidst other contention factors. N...

  Introduction:   A recent upgrade from version 19.21 left a customer grappling with a perplexing performance decline, marked by a surge in "free buffer waits." Tasks that once took a manageable two hours were suddenly stretching beyond the tolerable 10-hour mark, prompting a closer examination of the underlying issues. The customer had implemented a multi-tenant architecture utilizing a single Pluggable Database (PDB).   Unveiling the Culprit:   The initial investigation pinpointed a conspicuous increase in "free buffer waits," casting a shadow on system efficiency and causing disruptions in the normal flow of operations. Recognizing the critical nature of this bottleneck, the focus shifted to conducting a thorough hanganalyze to unravel the intricacies of the problem. Chains most likely to have caused the hang:   [a] Chain 1 Signature: 'rdbms ipc message'<='free buffer waits'       Chain 1 Signature Hash: 0x8e1d98d...

In today's rapidly evolving digital landscape, developers are in constant pursuit of tools that make application development faster, simpler, and more versatile. Oracle Database 23c emerges as a game-changer, delivering a comprehensive and user-friendly converged database for developers seeking to craft a wide array of applications, including microservices, graph-based solutions, document management, and relational databases. In this blog, we'll provide an overview of some of the exciting features and improvements introduced in Oracle Database 23c. In subsequent blogs, we will delve deeper into each of these topics to help you unlock the full potential of this cutting-edge database release. Many Datatype and SQL Enhancements😊 Oracle Database 23c introduces a host of enhancements in terms of datatypes and SQL capabilities. These improvements include: - Boolean Datatype: Simplify logical expressions and improve data accuracy. - Direct Joins for Update: Streamline update operatio...

Introduction Oracle Database's SQL Monitor is a powerful tool that provides deep insights into the execution of SQL statements, offering DBAs and developers crucial information for optimizing query performance. In this guide, we will delve into the various aspects of SQL Monitor, from understanding its default behavior to generating real-time and historical reports. Whether you're new to SQL Monitor or a seasoned user, this guide aims to provide valuable insights for effectively utilizing this tool. Default Behavior and Forcing Monitoring SQL Monitor automatically tracks SQL statements that run in parallel or consume at least 5 seconds of combined CPU and I/O time during a single execution. However, if you want to monitor specific SQL statements, you can include the `MONITOR` hint within the statement itself. For instance: SQL SELECT /*+ MONITOR */ count(*) from table you can force monitoring by setting the event "sql_monitor" at the system level: SQL ALTER SYSTEM SET...