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Continue reading →: Simulating Oracle Performance Hub with Text-Based ASH Visualizations
The Performance Hub in Oracle Enterprise Manager Cloud Control is an integrated dashboard for performance monitoring and diagnostics. However, this useful graphical tools may not always be available due to access limitations or licensing restrictions. Fortunately, all graphical representations are inherently supported by underlying commands. Specifically, the Performance Hub is…
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Continue reading →: Monitoring SQL Execution Plan Changes
If a SQL statement’s performance suddenly degrades, one possible cause could be a change in its execution plan. The following query can be used to identify when and how the execution plan has changed: The commented line in the SQL query serves as an optional filter condition. If uncommented, it…
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Continue reading →: Should Database be Blamed for Slow Response?
When an end user experiences a slow response from an application, it can sometimes be difficult to determine whether the issue is caused by the application layer (middleware) or the database layer. This often leads to discussions (and sometimes arguments) between the application developer and the database administrator (DBA) as…
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Continue reading →: Monitoring and Investigating Logon Storms in Oracle Databases
A logon storm refers to a situation where there are an unusually high number of logins within a short period of time, which can lead to serious performance issues or even denial of service. While logging into an Oracle database is expensive, an often overlooked fact is that logging off…
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Continue reading →: Identify the Slowest Step in a SQL Execution Plan with ASH
You may wonder which step of a SQL execution plan is the slowest. To answer this question, You have several options: SQL Monitor: This feature shows information either for long-running queries which consumes at least 5 seconds of CPU or I/O, or for all parallel queries. However, it does not…
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Continue reading →: Troubleshooting MySQL Server Startup Issues Without Error Log
When MySQL server goes wrong, your first instinct maybe check the error log file. However, if the server fails to start due to incorrect options, you might not find any messages in the error log file, as even the option to specify the error file might not have worked. Here…
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Continue reading →: Installing Oracle 19c on Linux 9: Overcoming Compatibility Issues (INS-08101)
Oracle Database 19c base release (19.3) was introduced before the release of Linux 9, leading to certain compatibility issues during installation. This guide will help you navigate and resolve these issues The Oracle 19.3 installer does not recognize Linux 9. To bypass this, set the CV_ASSUME_DISTID environment variable to simulate…
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Continue reading →: Script: Generating Focused AWR Reports
Analyzing Oracle AWR reports from my clients is one of my daily tasks. A common challenge is that these reports often cover too broad a timeframe, diluting the severity of performance issues. To address this, I developed the following script that automates AWR reports generation with a narrow focus. When…
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Continue reading →: Transporting AWR Data Using Oracle’ Built-in scripts: awrextr.sql and awrload.sql
The Automatic Workload Repository (AWR) holds valuable data for Oracle DBAs to analyze database performance. However, accessing and analyzing this data can be time-consuming and resource-intensive. To overcome these challenges, Oracle offers tools to transport AWR data to a separate environment for analysis. This approach enables technicians to perform diagnostics…
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Continue reading →: TroubleShooting Oracle Database Connection Failure (ORA-12514 or TNS-12514)
The ORA-12514 (or TNS-12514) error is a common issue encountered by many newcomers when connecting to an Oracle database. It generally indicates that the connection to the database instance can’t be established. In this article, I’ll guide you through troubleshooting this error. Symptoms When attempting to connect to an Oracle…
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