ORACLE TUNING - IDENTIFYING LONG RUNNING SQL FOR A TIME PERIOD

Methods for Monitoring Long-Running SQL Queries :
Several methods can be employed to monitor long-running SQL queries in Oracle :
Monitoring long-running SQL queries is an essential aspect of Oracle database tuning. Long-running queries can impact the overall performance of the database, and identifying and optimizing them can lead to significant improvements.

Here are some steps and tools you can use to monitor and tune long-running SQL queries in Oracle:
  1. V$SESSION_LONGOPS View : This view provides information about currently running SQL statements that have exceeded a specified duration. You can query this view to identify queries that are taking longer than expected.

  2. AWR (Automatic Workload Repository) : AWR collects performance statistics over time, including information about long-running SQL queries. You can analyze AWR reports to identify historical long-running queries and trends in query execution time.

  3. STATSPACK : STATSPACK is another tool that collects performance statistics, including information about long-running SQL queries. STATSPACK snapshots can be used to compare query performance over time and identify potential issues.

  4. Oracle Enterprise Manager : Oracle Enterprise Manager provides a comprehensive monitoring solution that includes the ability to identify long-running SQL queries. You can use Enterprise Manager to set alerts for long-running queries and investigate them in detail.

  5. Real-Time SQL Monitoring : Real-time SQL monitoring tools provide a dynamic view of currently executing SQL statements, including information about their execution time and resource consumption. This allows you to identify long-running queries as they are happening and take immediate action if necessary.

  6. Oracle Enterprise Manager (OEM): Performance Pages: OEM provides a set of performance monitoring pages where you can view and analyze SQL statements, including their execution plans, resource usage, and historical performance metrics.

  7. SQL Tuning Advisor : Use SQL Tuning Advisor to analyze high-load SQL statements and receive recommendations for improving their performance.

  8. Automatic Workload Repository (AWR) : AWR collects and stores performance statistics for the database. You can use the AWR reports to identify the top SQL statements consuming resources.Generate an AWR report to analyze the historical performance of SQL statements.

  9. Oracle SQL Developer : SQL Developer provides a SQL Tuning Advisor that can analyze SQL statements and suggest recommendations for performance improvement. You can also use the "Autotrace" feature to get execution plans and statistics for SQL queries.

  10. V$ Views : Utilize various dynamic performance views (V$ views) to query information about SQL execution, waits, and other performance-related details. Examples include V$SQL, V$SQLSTATS, and V$SESSION.

  11. Oracle Trace : Use Oracle Trace to trace the execution of specific SQL statements. Tracing can provide detailed information about the execution plan and resource usage. You can enable SQL trace for a session using the DBMS_MONITOR package.

  12. Custom Scripts : Develop custom scripts to monitor and log long-running queries based on criteria such as execution time, CPU usage, and I/O. Use tools like EXPLAIN PLAN to analyze the execution plan of SQL statements.

  13. Identifying Top SQL Statements : Identify the SQL statements with high resource consumption using AWR reports or by querying relevant V$ views. Focus on queries with high CPU time, I/O waits, and elapsed time.

  14. Indexing and Query Optimization : Analyze the execution plans of long-running queries and consider creating or modifying indexes to improve performance. Rewrite or optimize SQL queries for better performance.

  15. Regular Performance Monitoring : Set up regular performance monitoring and alerting to identify long-running queries in real-time. Establish baseline performance metrics and compare them with the current performance.


(Oracle Tuning - What is Expected for Tuning)