(10393) Database Performance Tuning Hands-On Lab

Transcription

1 (10393) Database Performance Tuning Hands-On ASH Analytics Real-time ADDM SQL Performance Analyzer

2 Objective: Database Performance Hands-on The objective of this lab to provide exercises designed to showcase new database performance management and data management capabilities in Oracle Enterprise Manager Cloud Control 12c. Functional Coverage: In this lab you will go through important features in the following functional areas: A. Database Performance management A1. ASH Analytics A2. Real Time ADDM A3. SQL Performance Analyzer environment setup This lab will have a workload started for you. If you don t see a workload running, please ask the system administrator to make sure to start the workload. NOTE: The graphs you see in this workbook may not match those on your screen. Page 2 of 24

3 Estimated Time to Complete Use Case: 15 minutes A1. ASH Analytics Business Case Oracle Enterprise Manager 12c introduces ASH Analytics, a new tool to explore the ASH (Active Session History) data that allows the administrator to rollup, drilldown, and slice or dice performance data across various performance dimensions. With the ability to create filters on various dimensions, identifying performance issues has never been easier. The built-in Loadmap view allows administrators to explore performance data using predefined performance dimension hierarchies. 2. Understanding the ASH Analytics page 1.1 Log on to Enterprise Manager using login -> dbuser / oracle Navigate to prod database Ash Analytics page via menu Targets Databases Choose -> prod.oracle.com as your database. Page 3 of 24

4 Navigate to ASH Analytics page from the specific database page via Performance ASH Analytics 1.3 On the Database login page, for Credential select Named, wait for login credentials to auto-populate with Credential Name being DB-SYS-GLOBAL and click Login button. Tip: If you have already logged to this database earlier, you will not be shown this page. Page 4 of 24

5 1.4 Shown below is the ASH Analytics Home Page. Notice the following: Select the Hour Time Period for investigation: Use the slider at the top of the chart to select a time period which has a high workload. The graph below the time window is a close-up detail of the time window s time period. Click on Day or Week period to view different levels across days then choose Hour. 1.6 The detail graph s drop-down menu defaults to Wait Class. The graph s legend on the right always matches the drop-down menu on the upper left. Page 5 of 24

6 1.7 Review the different Wait Classes: In the 2 nd chart from the top, observe the detailed view of the time window that has been selected By default the wait class dimension is selected. Observe the different wait classes for the window selected (blue for USER_IO, green for CPU etc.) 1.8 Become familiar with the different dimensions: For example, change the dimension from Wait Class to SQL ID. From the drop down, choose Top Dimensions -> SQL ID. Observe the change in the chart. The use of different performance dimensions allows the user to get a perspective of what is currently running and how the system resources are being utilized. Page 6 of 24

7 1.9 Let s examine the different filtering capabilities of ASH Analytics: Select Service as the Top Dimension. From the drop down, select Top Dimensions -> Service Click on the chart for the service prod.oracle.com and set it as a filter. Note: Depending on the workload characteristics and time period chosen you might not see the exactly the same services. If you don t find prod.oracle.com then choose the service with biggest block of color in the graph. Page 7 of 24

8 1.9.3 Once the filter is set, it will be indicated next to the Filters label. This filtered view shows the wait classes view for the specified service Observe how view changes with filter. Let s see how other dimensions are affected by the same filter. With the filter enabled, change the dimension from Wait Class to Module. From the drop-down select Top Dimension Module. Page 8 of 24

9 1.9.5 Observe the breakdown of waits by module. In the table at the bottom by default you can view the SQL ID, and User Session by Average Active Session. Drilling down into the SQL ID is NOT included in this lab, although the sql details page is accessible by clicking on the sql_id (please do not click the sql_id) Remove all the filters by clicking on the icon, then select the Wait Class via drop down Top Dimension Wait Class Page 9 of 24

10 1.11 Explore the Load Map view: Click on the Load Map button Select a predefined view - Simple mode, and -> Service,Module,SQL ID. Page 10 of 24

11 1.13 Drag the slider to 3 to increase the number of visible dimensions: The SQL IDs will be added to the chart Experiment with other pre-set treemaps and add filters: Select different Load Map dimensions and change from 2 to 3 to understand how the chart changes. Page 11 of 24

12 A2. Real-Time ADDM Environment Details: The target database is running a load on the sample schema provided via the Examples (or companion) software accompanying the Oracle database software. There are other schemas created to simulate specific performance scenarios. Estimated Time to Complete Use Case: 10 minutes Business Case This use case is intended to give an idea of the basic functionality of the Real-Time ADDM (where ADDM stands for Automatic Database Diagnostics Monitor). Real-Time ADDM is an innovative way to analyze problems in extremely slow or hung databases. Real-Time ADDM runs through a set of predefined criteria to analyze the current performance and helps the DBA to resolve deadlocks, hangs, shared pool contentions and many other exception situations which force the administrator to bounce their databases today. 4. Understanding Real-Time ADDM 4.1 You should already be logged on to Enterprise Manager. If you are not, please follow the instructions detailed in earlier section of this workbook. 4.2 This exercise requires users to launch a job that causes a hung job. In order to do that, go to the Job Library page. Select Enterprise -> Job -> Library 4.3 Initiate the Real-Time ADDM Load: Select the radio button for job REAL-TIME ADDM - SETUP DATABASE HANG, and click Submit. Page 12 of 24

13 4.4 When the job screen opens, click submit again. You will see a Confirmation message with the Job Name in it. Click on that job name. Now make sure the job Status says Running. If the Status column says Scheduled (1) then click the Refresh icon (2) until the Status column says Running. Then go to the next step below. The job will run for 10 minutes the duration of the exercise. Page 13 of 24

14 4.5 Log out of Enterprise Manager Cloud Control (and all objects you are connected to if logging out gives you that choice). Then log back in as dbuser / oracle Go to Targets -> Databases. 4.7 Select the database -> prod.oracle.com Page 14 of 24

15 4.8 Given that the job that we just launched put the database in a hung state, you might receive messages that it is Trying to connect to the database, or that it failed to connect. This is expected. NOTE: DON T WAIT for the connection to happen (because the database is hung), just proceed to the next step. 4.9 From the Database Home Page, select target menu Performance -> Real-Time ADDM On the Database login page, select Named Credentials, wait for login credentials to auto-populate as DB- SYS-GLOBAL and click Submit button. Tip: If you had stayed logged into the database instead of logging out, you may not have seen this page. Page 15 of 24

16 4.11 When the Real-Time ADDM page opens, you will see two sections - the graphical section on top, and the Details section on the bottom. Real-time ADDM is able to access the database even though it s hung In the Details section, click on the Start button. Because the database is hung: 1. Observe the Normal Connections window will not be populated, but instead will continue spinning 2. When the Number of Findings turns to 1 3. Then click on the Findings tab. Page 16 of 24

17 4.13 Click on the Findings tab. Here you will see the offending process id. Make note of the operating system process id. In this particular example, there is only one offending OS process. Note: Depending on the load characteristics, you might see two processes instead of one. In that case please kill both the processes in the next step. To kill the process, you ll need to connect to the VM. You can either use VNC viewer (VNC Viewer, Tight VNC) or PuTTY. VNC server name : <em12.oracle.com:1 or whatever the instructor says> VNC and OS Passwords : oracle To open a terminal session in the VNC, right click on desktop and click Open Terminal. Page 17 of 24

18 4.15 To kill the OS process, execute kill -9 <process id> in the command window. The <process id> should be the same one(s) you saw in the Findings tab in step In this lab book example, process id is -> Return to the Real Time ADDM page. Click on the Progress tab. Page 18 of 24

19 The page might take seconds to refresh itself, but once it does, it should show status as (1) FINISHED reflecting that the database is no longer in a hung state. Click on the (2) Hang Data tab. The OS process ID is the same one we just killed. This screen shows the database was hung and also shows the sessions, modules and users affected This completes the Real Time ADDM exercise. Please close your VNC terminal and window. Page 19 of 24

20 Estimated Time to Complete Use Case: 8 minutes A3. SQL Performance Analyzer Business Case SQL Performance Analyzer (SPA), introduced in Oracle Database 11g, can help predict and prevent SQL execution performance problems caused by system changes. SQL Performance Analyzer provides a granular view of the impact of changes on SQL execution plans and execution statistics by running the SQL statements in isolation before and after a change. In this lab we will use SQL Performance Analyzer to simulate the improvement in interconnect IO that can be seen by moving from legacy hardware to the Oracle Exadata Database Machine. 2. Understanding SQL Performance Analyzer 3.1 You should already be logged on to Enterprise Manager as dbuser / oracle12. If you are not, please follow the instructions detailed in earlier section of this workbook. Go to Targets -> Databases and select prod.oracle.com as your database. Now choose Performance -> SQL -> SQL Performance Analyzer. Page 20 of 24

21 3.2 Select Named Credential (it should auto-populate as DB-SYS-GLOBAL) and click Login. 3.3 Click on Exadata Simulation as the workflow. 2.1 Now, let s select a job and compare its current performance to its estimated performance on Exadata. 1. Type in a Task Name. 2. Click on the SQL Tuning Set search icon then 3. Choose TPCH and 4. click Select. Page 21 of 24

22 3.4 The SQL Tuning Set name will auto-fill, then click on Submit to submit the job. 3.5 You ll see a Confirmation that the job has been created. If the Last Run Status says Processing, then click the Refresh button until the status says Completed. 3.6 Once the job is Completed, click on View Latest Report for a rich summary report of the job s run. Page 22 of 24

23 3.7 SQL Performance Analyzer shows us the order of magnitude improvement in for I/O Interconnect Bytes when using Exadata compared to traditional solutions. SQL Performance Analyzer estimates a 91% improvement overall. It also provides us estimated improvement for each SQL in the SQL Tuning Set. Click on a SQL statement that shows the highest degree of improvement. 3.8 We see a summary of useful pertinent metrics, all of which show dramatic improvement in SQL Trial 2, which was simulating Exadata s impressive interconnect performance. Scroll down the page for more explanation, a quite striking explanation: Page 23 of 24

24 Here we see the execution plans for the two runs of the query. As we can see, in SQL Trial 2 Exadata s predicate push-down capability pushed the most expensive predicate down to the Exadata storage servers. We can even see the precise predicate that got pushed down. This ends the lab work on Enterprise Manager Cloud Control 12c. Hope you enjoyed the lab! Comments and feedback are welcome. Send comments and feedback to: Robert Ash <robert.ash@oracle.com> Page 24 of 24