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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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Continue reading →: Diagnosing Parsing Issue with ASH
Parsing, especially hard parsing, are non-productive operation and can consume significant system resources, leading to library cache contention. ASH can be used to diagnose and analyze excessive parsing through its sampling mechanism. This blog explores how to effectively use ASH to identify parsing issues. Simulating a Parsing Issue First, we…
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Continue reading →: Sample-Based SQL Runtime Calculation: Deduce SQL execution time with ASH
In the realm of database performance monitoring, identifying and resolving sporadic performance issues caused by outlier SQL statements can be particularly challenging. Traditional tools often rely on periodic snapshot and averages, which average out spikes and outliers, this limitation therefore obscures the identification of transient performance anomalies. This blog is…
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Continue reading →: Script: Monitoring Running SQL in Oracle Database in Real Time
The output below is an example you can expect:
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