Oracle Database CPU Utilization Query

Oracle Database CPU Utilization Query is a critical tool for monitoring and optimizing the performance of Oracle databases. With organizations increasingly relying on complex database systems to store and process massive amounts of data, efficiently managing CPU utilization is essential for maintaining optimal system performance.

By analyzing and understanding CPU utilization, administrators can identify bottlenecks, optimize resource allocation, and troubleshoot performance issues. This query provides valuable insights into the usage patterns, workload distribution, and overall health of the Oracle database environment. With this information, organizations can make informed decisions to ensure efficient utilization of resources and deliver optimal user experiences.

Understanding Oracle Database CPU Utilization Query

The CPU utilization of an Oracle database is a critical metric that determines the level of system performance and resource allocation. To optimize the performance and efficiency of an Oracle database, it's essential to monitor and analyze CPU utilization. Fortunately, Oracle provides a powerful query to retrieve valuable information about CPU utilization, allowing database administrators to make informed decisions and take appropriate actions.

The V$SYSMETRIC_HISTORY View

One of the most useful views for investigating CPU utilization in Oracle Database is the V$SYSMETRIC_HISTORY view. This view provides historical information about various system metrics, including CPU utilization.

The V$SYSMETRIC_HISTORY view contains the following columns relevant to CPU utilization:

• INTSIZE_CSEC: This column represents the difference in hundredths of a second from the previous row's INTSIZE_CSEC value. It helps in calculating the time duration between metric samples.
• METRIC_ID: This column indicates the metric being monitored. In the case of CPU utilization, the metric ID is typically 232.
• INTSIZE_CAPTURE: This column represents the system change number (SCN) of the respective metric sample.
• AVERAGE: This column specifies the average value of the metric sample.

By querying the V$SYSMETRIC_HISTORY view and filtering on the metric ID of CPU utilization, database administrators can retrieve historical data to analyze and diagnose CPU-related performance issues.

Assessing CPU Utilization with the V$SYSMETRIC_HISTORY View

When analyzing CPU utilization in Oracle Database, it's essential to consider various factors and assess the metrics available through the V$SYSMETRIC_HISTORY view. Here are some key steps to assess CPU utilization:

Step 1: Identify the Relevant Metric IDs

Before querying the V$SYSMETRIC_HISTORY view for CPU utilization, it's crucial to determine the metric ID associated with CPU usage. Generally, the metric ID for CPU utilization is 232. By identifying the relevant metric ID, you can filter the data and focus on CPU-related metrics.

To find the metric ID for CPU utilization, you can execute the following query:

SELECT METRIC_NAME, METRIC_ID
FROM DBA_HIST_METRIC_NAME
WHERE METRIC_NAME LIKE 'Host CPU Utilization%';

This query retrieves the metric name and ID associated with CPU utilization from the DBA_HIST_METRIC_NAME view, allowing you to identify the relevant metric ID for CPU usage.

Step 2: Query the V$SYSMETRIC_HISTORY View

Once you've identified the metric ID for CPU utilization, you can query the V$SYSMETRIC_HISTORY view to retrieve the historical CPU utilization data. Here's a sample query:

SELECT
    TRUNC(C.RECORD_TIME, 'MI') AS "SAMPLE_TIME",
    ROUND(AVERAGE/100, 2) AS "CPU_UTILIZATION"
FROM
    V$SYSMETRIC_HISTORY C,
    DBA_HIST_METRIC_NAME D
WHERE
    C.METRIC_ID = D.METRIC_ID
    AND D.METRIC_NAME LIKE 'Host CPU Utilization%'
    AND C.INTSIZE_CAPTURE = (
        SELECT MAX(INTSIZE_CAPTURE)
        FROM V$SYSMETRIC_HISTORY
        WHERE C.METRIC_ID = METRIC_ID
    )
ORDER BY
    C.RECORD_TIME ASC;

This query retrieves the sample time and CPU utilization from the V$SYSMETRIC_HISTORY view, specifically for the metric ID associated with CPU usage. The TRUNC() function helps in rounding the sample time to the nearest minute, while the ROUND() function converts the CPU utilization from hundredths of a second to a percentage.

Step 3: Analyze the Results

Once you have retrieved the CPU utilization data from the V$SYSMETRIC_HISTORY view, you can analyze the results to identify any patterns or trends. Look for instances of high CPU utilization, spikes, or prolonged periods of high utilization.

By correlating the CPU utilization data with other system metrics, such as the number of concurrent sessions, SQL statements, or I/O activity, you can gain a comprehensive understanding of the factors impacting CPU utilization and make informed decisions to optimize performance.

Using Cursor Sharing for Efficient CPU Utilization

In addition to monitoring and analyzing CPU utilization, Oracle Database offers features that can enhance CPU efficiency. One such feature is cursor sharing, which allows the database to reuse a SQL statement's parsed execution plan to minimize the CPU resources required for subsequent executions.

Enabling cursor sharing can significantly reduce CPU usage in environments where multiple similar SQL statements are executed repeatedly. The cursor sharing mode can be set to one of the following values:

• EXACT: This mode ensures the parsed execution plan is shared only if the SQL statements are identical in every aspect.
• SIMILAR: This mode allows the parsed execution plan to be shared for SQL statements with similar structures, even if there are differences in literal values.

By leveraging cursor sharing, Oracle Database optimizes CPU utilization by reducing the parsing overhead for similar SQL statements, resulting in improved performance and resource efficiency.

Monitoring CPU Utilization using Oracle Enterprise Manager

Oracle Enterprise Manager (OEM) provides a comprehensive solution for monitoring and managing Oracle Databases, including CPU utilization. Within OEM, the "Performance" tab offers various CPU-related metrics and graphs to monitor system performance.

Using OEM, you can view real-time CPU utilization, historical trends, and statistical data to gain insights into the overall system health and identify any potential bottlenecks. The intuitive interface and interactive dashboards make it easier for database administrators to monitor and analyze CPU utilization, ensuring optimal performance and resource utilization.

Integrating OEM Metrics with V$SYSMETRIC_HISTORY View

In addition to utilizing OEM's monitoring capabilities, you can also integrate the metrics provided by OEM with the data from the V$SYSMETRIC_HISTORY view. This integration allows for a more comprehensive analysis of CPU utilization, combining real-time and historical data for deeper insights.

By leveraging both OEM and the V$SYSMETRIC_HISTORY view, database administrators can monitor CPU utilization in real-time, track historical trends, and identify any abnormal patterns or performance issues that require attention.

Exploring Different Dimensions of Oracle Database CPU Utilization Query

In addition to the V$SYSMETRIC_HISTORY view and cursor sharing, there are other aspects to consider when exploring Oracle Database CPU utilization query. Let's delve into these dimensions:

The V$SYSSTAT View

Another valuable view for monitoring CPU utilization in Oracle Database is the V$SYSSTAT view. This view provides statistics accumulated since the database instance started, including CPU-related statistics.

The V$SYSSTAT view contains a wide range of statistics, and some important ones related to CPU utilization are:

• CPU used by this session: This statistic represents the CPU time (in hundredths of a second) used by the current session since its start.
• background cpu time: This statistic indicates the amount of CPU time (in hundredths of a second) utilized by background processes since the database instance started.
• parse time elapsed: This statistic represents the elapsed parse time (in hundredths of a second) since database instance start.
• hard parse elapsed time: This statistic indicates the total elapsed time (in hundredths of a second) for hard parses since the instance started.

By querying the V$SYSSTAT view and filtering on the relevant statistics, you can gather additional insights into CPU utilization and its distribution across various sessions and background processes.

The DBA_HIST_ACTIVE_SESS_HISTORY View

The DBA_HIST_ACTIVE_SESS_HISTORY view provides historical session-level details, including CPU utilization, for a specified time interval. It can be a valuable resource for analyzing CPU-intensive sessions and identifying resource-consuming queries.

The DBA_HIST_ACTIVE_SESS_HISTORY view contains relevant columns such as:

• SESSION_ID: This column represents the unique identifier for each session.
• CPU_WAIT_TIME: This column indicates the CPU wait time (in hundredths of a second) for each session.
• CPU_WAITS: This column specifies the number of times a session has waited for CPU resources.
• SQL_ID: This column represents the SQL statement ID associated with the session.

By combining the information from the DBA_HIST_ACTIVE_SESS_HISTORY view with other relevant views and queries, you can gain a deeper understanding of CPU utilization patterns, identify resource-intensive queries, and improve overall database performance.

Using AWR Reports for CPU Utilization Analysis

The Automatic Workload Repository (AWR) in Oracle Database captures and stores performance-related data for further analysis. AWR reports provide detailed insights into CPU utilization, allowing database administrators to identify potential bottlenecks and make performance optimizations.

To generate an AWR report, you can use the DBMS_WORKLOAD_REPOSITORY package. Here's an example of generating an AWR report for a specific time interval:

DECLARE
    dbid        NUMBER;
    inst_num    NUMBER;
    begin_snap  NUMBER;
    end_snap    NUMBER;
    report_type VARCHAR2(30) := 'html';
BEGIN
    SELECT DBID, INSTANCE_NUMBER
    INTO dbid, inst_num
    FROM V$DATABASE;

    SELECT MIN(SNAP_ID)
    INTO begin_snap
    FROM DBA_HIST_SNAPSHOT
    WHERE BEGIN_INTERVAL_TIME BETWEEN TO_TIMESTAMP('2022-01-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS') 
                                AND TO_TIMESTAMP('2022-01-02 23:59:59', 'YYYY-MM-DD HH24:MI:SS')
                                AND INSTANCE_NUMBER = inst_num;

    SELECT MAX(SNAP_ID)
    INTO end_snap
    FROM DBA_HIST_SNAPSHOT
    WHERE BEGIN_INTERVAL_TIME BETWEEN TO_TIMESTAMP('2022-01-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS') 
                                AND TO_TIMESTAMP('2022-01-02 23:59:59', 'YYYY-MM-DD HH24:MI:SS')
                                AND INSTANCE_NUMBER = inst_num;

    DBMS_WORKLOAD_REPOSITORY.AWR_REPORT_HTML(
        dbid          => dbid,
        instance_number => inst_num,
        begin_snap    => begin_snap,
        end_snap      => end_snap,
        report_type   => report_type
    );
END;
/

This PL/SQL block generates an AWR report in HTML format for a specific time interval. You need to specify the desired date range by modifying the TO_TIMESTAMP() function parameters. The report provides detailed information on CPU utilization, including top SQL statements, CPU wait events, and CPU usage distribution.

Conclusion

The utilization of CPU resources in an Oracle database plays a pivotal role in determining the overall system performance and efficiency. By leveraging the insights gained from querying the V$SYSMETRIC_HISTORY, V$SYSSTAT, DBA_HIST_ACTIVE_SESS_HISTORY, and A

Oracle Database CPU Utilization Query

In Oracle Database, CPU utilization is an important metric to monitor the performance of the system. It helps in ensuring that the CPU resources are efficiently utilized and not overburdened. To query the CPU utilization in Oracle Database, the following steps can be followed:

• Connect to the Oracle Database using SQL*Plus or any other database management tool.
• Execute the query: SELECT ROUND((cpu_usage * 100 / total_cpu), 2) AS cpu_utilization FROM v$sysmetric WHERE metric_name = 'Host CPU Utilization (%)';
• This query fetches the CPU utilization percentage from the system metrics view (v$sysmetric) and calculates the utilization ratio.
• The result will show the current CPU utilization percentage for the Oracle Database.

Monitoring CPU utilization in Oracle Database helps in identifying any performance bottlenecks and allows for proactive optimization measures to be taken. It is recommended to regularly monitor CPU utilization to ensure optimal system performance.

Frequently Asked Questions

In this section, we will answer some frequently asked questions about Oracle Database CPU Utilization Query.

1. How can I monitor the CPU utilization of my Oracle Database?

To monitor the CPU utilization of your Oracle Database, you can use the following query:

SELECT ROUND(100 * (cpu_busy_time / (elapsed_time * processor_count)), 2) as cpu_utilization
FROM v$sysstat
WHERE name = 'CPU used by this session';

This query calculates the CPU utilization percentage by dividing the total CPU busy time by the elapsed time multiplied by the number of processors. It provides you with valuable insights into the CPU usage of your Oracle Database.

2. What should I consider a high CPU utilization percentage for my Oracle Database?

The ideal CPU utilization percentage for an Oracle Database can vary depending on factors such as the hardware configuration, workload, and performance objectives. However, as a general guideline, a CPU utilization percentage above 80% is considered high and may indicate a need for optimization or capacity upgrades.

3. How can I identify the top CPU-consuming SQL statements in my Oracle Database?

To identify the top CPU-consuming SQL statements in your Oracle Database, you can use the following query:

SELECT sql_id, elapsed_time, cpu_time, executions, sql_text
FROM v$sqlarea
ORDER BY cpu_time DESC;

This query retrieves the SQL statements from the shared pool and sorts them based on their CPU time. The SQL statement with the highest CPU time indicates the one consuming the most CPU resources.

4. Can I limit the CPU utilization of specific SQL statements in my Oracle Database?

Yes, you can limit the CPU utilization of specific SQL statements in your Oracle Database using Resource Manager. Resource Manager allows you to prioritize and allocate CPU resources to different database operations based on predefined resource plans.

5. How can I optimize the CPU utilization of my Oracle Database?

To optimize the CPU utilization of your Oracle Database, you can follow these best practices:

• Identify and tune poorly performing SQL statements
• Optimize database schema and indexes
• Implement connection pooling
• Regularly monitor and analyze CPU utilization
• Consider hardware upgrades if necessary

In summary, the Oracle Database CPU Utilization query is a powerful tool for monitoring and optimizing the performance of your Oracle database. By analyzing the CPU utilization metrics, you can identify bottlenecks, tune your queries, and improve overall system efficiency.

With this query, you can track the CPU usage over time, pinpoint high-consuming sessions or SQL statements, and take appropriate actions to optimize resource utilization. It provides valuable insights into the workload patterns and helps you make informed decisions to enhance the database performance and ensure efficient utilization of system resources.