juliandyke.com 1 © Julian Dyke Julian Dyke Independent Consultant Is RAT Worth Catching?

juliandyke.com 2 © Julian Dyke Introduction  Real Application Testing (RAT)  Introduced in Oracle 11gR1  Also referred to as Database Replay  This presentation describes RAT in Oracle 11gR2  Separately licenced option.  Processor license *  Real Application Testing$11,500  Some comparative processor license *  Enterprise Edition$47,500  Real Application Clusters$23,000  Partitioning Option$11,500  * Source – Oracle Technology Global Price List – 08Nov12

juliandyke.com 3 © Julian Dyke Database Replay Client Oracle Database Storage Workload Capture Production Test Workload Preprocessing Workload Replay Analysis & Reporting Storage Application Tier Oracle Database Storage Replay Client

juliandyke.com 4 © Julian Dyke Prerequisites  Workload capture is supported on the following versions:  A one-off patch is required to implement workload capture in versions earlier than  Workload replay is supported in and above  Oracle requires one-off patch VersionOne-off Patch

juliandyke.com 5 © Julian Dyke Capture User  The workload can be captured by SYS  Alternatively a new user can be created to manage the workload capture. For example: CREATE USER ratuser IDENTIFIED BY ratuser DEFAULT TABLESPACE SYSAUX TEMPORARY TABLESPACE TEMP ACCOUNT UNLOCK; GRANT MGMT_USER TO ratuser; GRANT EXECUTE_CATALOG_ROLE TO ratuser GRANT SELECT_CATALOG_ROLE TO ratuser; GRANT CREATE ANY DIRECTORY TO ratuser; GRANT DROP ANY DIRECTORY TO ratuser; GRANT SELECT ON DBA_WORKLOAD_CAPTURES TO RATUSER; GRANT UNLIMITED TABLESPACE TO ratuser; GRANT SELECT ANY TABLE TO ratuser;

juliandyke.com 6 © Julian Dyke Capture Directory  Captured workload is stored in binary files in a directory tree below the capture directory  Capture will stop if capture directory is full  For RAC databases either:  Use a shared file system for workload capture  Use local file systems and subsequently merge contents  For example: $ mkdir /home/oracle/capture1 $ chmod –R 777 /home/oracle/capture1 sqlplus ratuser/ratuser SQL> CREATE OR REPLACE DIRECTORY capture1 AS ‘/home/oracle/capture1’;

juliandyke.com 7 © Julian Dyke Capture Parameters  In Oracle and below, workload capture must be enabled using the PRE_11G_ENABLE_CAPTURE parameter  In Oracle and below:  Workload capture can be enabled using :  $ORACLE_HOME/rdbms/admin/wrrenbl.sql  Workload capture can be disabled using:  $ORACLE_HOME/rdbms/admin/wrrdsbl.sql  Workload capture is enabled by default in Oracle and above  The PRE_11G_ENABLE_CAPTURE parameter is not supported  Workload capture can also be enabled using Enterprise Manager ALTER SYSTEM SET pre_11g_enable_capture=true SID=‘*’; ALTER SYSTEM SET pre_11g_enable_capture=false SID=‘*’;

juliandyke.com 8 © Julian Dyke Starting a Workload Capture  To start a workload capture use the START_CAPTURE procedure: DBMS_WORKLOAD_CAPTURE.START_CAPTURE ( name => ‘CAPTURE1’, dir => ‘CAPTURE1’, duration=> 3600 );  Duration is specified in seconds  1 hour = 3600 seconds  24 hours = seconds  While capture is enabled a temporary file is created in the capture directory.  For example:  wcr_cap_0003n.start  The file contains 0 bytes and is deleted when the capture is disabled

juliandyke.com 9 © Julian Dyke RAT Trap - Restart the Database  Oracle recommends that the database is restarted immediately before any workload capture  Ensures that any on-going transactions are completed or rolled back before the capture begins  Reduces amount of divergence  Start workload capture immediately after database restart  Restart database in RESTRICTED mode using STARTUP RESTRICT  Login as SYS and start workload capture  Instance will automatically switch to UNRESTRICTED mode  Experience suggests that the database should be also restarted before any workload replay  Changes to system clock affect AWR snapshots

juliandyke.com 10 © Julian Dyke RAT Trap – Capture Restrictions  The following types of client request are known restrictions for workload capture  Direct path load of data from external files using utilities such as SQL*Loader  Non-PL/SQL based Advanced Queuing (AQ)  Flashback queries  Oracle Call Interface (OCI) based object navigations  Non SQL-based object access  Distributed transactions  Any distributed transactions that are captured will be replayed as local transactions

juliandyke.com 11 © Julian Dyke Capture Filters  By default all user sessions are recorded during workload capture  Workload filters can be configured to include or exclude sessions from the capture  Include filters specify user sessions that will be captured. Can be used to capture a subset of the workload  Exclude filters specify user sessions that will not be captured. Can be used to exclude sessions such as  Enterprise Manager Agent,  STATSPACK,  BMC Patrol  Quest Spotlight  Precise I3  etc

juliandyke.com 12 © Julian Dyke Workload Capture Directories and Files  In Oracle 11.2 and above START_CAPTURE creates subdirectories in capture directory  cap  capfiles  inst1  aa to aj  Each session stores data in a record file e.g. wcr_czq45h rec  Compressed file  XML-like format with elements and attributes  All SQL calls including  statement text  bind variables  execution time  rows returned  error code  Flushed periodically

juliandyke.com 13 © Julian Dyke Workload Capture Files  START_CAPTURE generates the following workload metadata (WMD) files automatically in the cap directory  wcr_scapture.wmd- Start capture details  wcr_fcapture.wmd- Finish capture details  In Oracle 11.2 and above START_CAPTURE automatically generates a capture report in the cap directory  wcr_cr.html- Capture report – HTML format  wcr_cr.text- Capture report – Text format

juliandyke.com 14 © Julian Dyke RAT Trap – Minimum CPU time  A replay requires a minimum of 5 minutes captured CPU time  CPU time NOT Elapsed Time  May be a problem for workloads that are:  I/O-bound  Network intensive  Application-bound  Workload capture period must be long enough to capture five minutes CPU  Can use SLEEP functions to artificially capture CPU  Does not work with PL/SQL DBMS_LOCK.SLEEP function  Works with JServer Java sleep class  Works with External C class

juliandyke.com 15 © Julian Dyke RAT Trap – Finishing Capture  Capture files are written using buffered I/O  Advantages are:  Lower overhead  Lower impact on workload  Disadvantages are:  Buffers are not flushed automatically  SQL statements can be “lost”  When capture ends or FINISH_CAPTURE is executed:  Timeout period is specified  Sessions will be informed during next database call  If sessions make a database call within timeout period  Capture file buffer will be flushed  Otherwise contents will be lost

juliandyke.com 16 © Julian Dyke Generating a Capture Report  Determine the capture ID from the capture name e.g.: SELECT id FROM dba_workload_captures WHERE name = ‘CAPTURE1’; ID 1  Generate the capture report e.g.: SET SERVEROUTPUT ON DECLARE l_clobCLOB BEGIN l_clob := dbms_workload_capture.report ( capture_id=>1, format => DBMS_WORKLOAD_CAPTURE.TYPE_TEXT ); DBMS_OUTPUT.PUT_LINE (l_clob); END; /

juliandyke.com 17 © Julian Dyke Generating a Capture Report  The capture report format can be:  DBMS_WORKLOAD_CAPTURE.TYPE_TEXT  DBMS_WORKLOAD_CAPTURE.TYPE_HTML  The capture report includes the following:  Details of workload capture including name, filters, date, time and SCN  Overall statistics including total DB time, number of logins, number of transactions  Profile of captured workload  Profile of workload not captured due to version limitations  Profile of uncaptured workload that was excluded by defined filters  Profile of uncaptured workload consisting of background process and scheduled jobs

juliandyke.com 18 © Julian Dyke Exporting the AWR  An export of the AWR is required for subsequent analysis on the replay system  To export the AWR use the EXPORT_AWR procedure. For example: BEGIN dbms_workload_capture.export_awr (capture_id=>1); END; /  This creates the following files in the capture directory:  wcr_ca.dmp – Data Pump export  wcr_ca.log – Data Pump log file  wcr_cap_uc_graph.extb – User calls graph

juliandyke.com 19 © Julian Dyke  AWR snapshots are required for subsequent reporting  Ensure that the AWR snapshots are exported before they exceed the AWR retention period and are automatically deleted RAT Trap – AWR Snapshots

juliandyke.com 20 © Julian Dyke Restore Strategy  A strategy is required to restore a pre-capture copy of the database to the replay system  One of the following methods can be used:  RMAN backup and restore  RMAN DUPLICATE command  Snapshot standby  Data Pump Import and Export  SAN replication  The database should be restored on the replay system to the point in time at the start of the capture Recommendation Enable flashback logging and test the replay before performing a recorded test

juliandyke.com 21 © Julian Dyke Replay Preparation  Restore pre-capture database to new home ALTER DATABASE OPEN RESETLOGS;  Modify archive log destination ALTER SYSTEM SET log_archive_dest_1 = ‘LOCATION=/11/oradata/ /arch MANDATORY REOPEN=300’;  Run standard upgrade ALTER SYSTEM SET compatibility = ’ ’ SCOPE = SPFILE; ALTER SYSTEM SET optimizer_features_enable = ’ ’ SCOPE = SPFILE;  Update COMPATIBILITY and OPTIMIZER_FEATURES_ENABLE parameters  Ensure replay database parameters have equivalent values to capture database parameters

juliandyke.com 22 © Julian Dyke Replay User  Replay can be performed by SYS user  Alternatively create a dedicated replay user e.g. RATUSER. $ sqlplus / as sysdba SQL> GRANT DBA TO ratuser;

juliandyke.com 23 © Julian Dyke Replay Directory  The contents of the capture directory should be copied across to the replay server.  It will be necessary to recreate the Oracle directory object: $ sqlplus ratuser/ratuser SQL> CREATE OR REPLACE DIRECTORY capture1 AS ‘/home/oracle/capture1’;

juliandyke.com 24 © Julian Dyke Replay Preprocessing  Pre-process the capture for replay.  For example: BEGIN dbms_workload_replay.process_capture ( capture_dir => ‘CAPTURE1’ ); END; /  Analyses the workload capture found in the CAPTURE_DIR  Creates workload replay metadata files required to replay the given workload capture  Can be run multiple times on same capture directory  Must be run in same database version as replay  Can run multiple replays following execution of PROCESS_CAPTURE

juliandyke.com 25 © Julian Dyke Replay Pre-processing  In Oracle the PROCESS_CAPTURE procedure creates a new subdirectory called pp in the capture directory containing the following files:  wcr_calibrate.html  wcr_commits.extb  wcr_conn_data.extb  wcr_data.extb  wcr_dep_graph.extb  wcr_login.pp  wcr_process.wmd  wcr_references.extb  wcr_scn_order.extb  wcr_seq_data.extb

juliandyke.com 26 © Julian Dyke Replay Preprocessing  To determine how long pre-processing will take use: SELECT dbms_workload_replay.process_capture_remaining_time FROM dual;  Returns an estimate of remaining capture time in minutes  An accurate estimate of remaining processing time cannot be determined during the first minute  Function returns NULL if invoked within first minute of capture pre- processing  To determine what percentage of capture pre-processing is complete use: SELECT dbms_workload_replay.process_capture_completion FROM dual;  Returns percentage of capture files that have already been processed  Percentage is updated every 60 seconds

juliandyke.com 27 © Julian Dyke Workload Analyzer  Workload Analyzer  Available in and above  Java program that analyses a workload capture directory  Identifies parts of captured workload that may not replay accurately e.g.  Insufficient data  Errors occurring during workload capture  Usage features not supported by Database Replay  Results are stored in capture directory in the following files:  wcr_cap_analysis.html  wcr_cap_analysis.xml  Executed automatically by Enterprise Manager during capture pre-processing  Must be invoked manually otherwise  Requires :  $ORACLE_HOME/jdbc/lib/dbranalyzer.jar  $ORACLE_HOME/jdbc/lib/dbrparser.jar  Java 1.5 or above

juliandyke.com 28 © Julian Dyke Workload Analyzer  Syntax is java –classpath \ $ORACLE_HOME/jdbc/lib/ojdbc5.jar:\ $ORACLE_HOME/rdbms/jlib/dbrparser.jar:\ $ORACLE_HOME/rdbms/jlib/dbranalyzer.jar \ oracle.dbreplay.workload.checker/CaptureChecker  - operating system path of the capture directory  - connection string of Oracle database (11.1 and above)  e.g.  In Oracle this utility only works with JDBC thin client  JDBC thick client (OCI) fails  Tested successfully with Java 1.6 and ojdbc6.jar  Analyzer will prompt for username/password of database user e.g. ratuser

juliandyke.com 29 © Julian Dyke RAT Trap - System Clock  Reset the system clock on the replay system to the start time of the capture  Ensure NTP daemon is disabled on replay server  Restart all database instances after resetting the system clock  Consider generating a new ID for the database to ensure AWR snapshots can still be created automatically after the system clock is reset

juliandyke.com 30 © Julian Dyke RAT Trap – External References  Reconfigure references to external systems to avoid impact on production systems during replay  References that should be resolved include:  Database Links  External Tables  Directory Objects  URLs  servers

juliandyke.com 31 © Julian Dyke Initialize Replay  After workload capture has been pre-processed, replay data can be initialized  Loads necessary metadata required by workload replay into tables  captured connection strings are loaded into a table where they can be remapped for replay  For example: BEGIN dbms_workload_replay.initialize_replay ( replay_name => ‘CAPTURE1_REPLAY1’, replay_dir => ‘CAPTURE1’ ); END; /  Known to populate the following base tables:  WRR$_REPLAYS  WRR$_CONNECTION_MAP

juliandyke.com 32 © Julian Dyke Remap Connections  During capture, connection strings used to connect to production system are captured  Connection strings must be remapped to replay system SELECT ‘EXEC dbms_workload_replay.remap_connection (‘||a.conn_id||’,’’(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP) (HOST= )(PORT= )) (CONNECT_DATA=(SID= )))’’);’ FROM dba_workload_connection_map a, dba_workload_replays b WHERE a.replay_id = b.id AND b.status = ‘INITIALIZED’ ORDER BY a.conn_id; Note that the TNS address is enclosed by a pair of two single quotes, NOT a pair of double quotes

juliandyke.com 33 © Julian Dyke RAT Trap – Remap Connections  Ensure that connections are remapped from the capture database to the replay database  If connections are not remapped, workload may be replayed against production database

juliandyke.com 34 © Julian Dyke Prepare Replay  Specify parameters for workload replay using the PREPARE_REPLAY procedure  For example:  PREPARE_REPLAY parameters include:  SYNCHRONIZATION – Determines how replay will be synchronized. Options are:  SCN – COMMIT order in captured workload is preserved during replay  OBJECT_ID – COMMIT order is maintained for relevant objects only. Relevant objects are objects referenced within current action  OFF – replay is unsynchronized  CONNECT_TIME_SCALE – Scales elapsed time from start of workload capture to time when session connects. Can be used to increase or decrease concurrency. Default is 100% EXECUTE dbms_workload_replay.prepare_replay (synchronization => TRUE);

juliandyke.com 35 © Julian Dyke Prepare Replay  PREPARE_REPLAY parameters (continued):  THINK_TIME_SCALE – Scales elapsed time between successive user calls from same session. Default is 100%. If 0 then no delays between user calls  THINK_TIME_AUTO_CORRECT – Automatically correct think time between calls when user calls take longer to complete during replay than capture  SCALE_UP_MULTIPLIER – Defines number of times workload is scaled up during replay  Each captured session will be replayed number of times specified by this parameter  Only one session in each set will execute both queries and updates  Remaining sessions in set will only execute queries  CAPTURE_STS – specifies whether or not to capture a SQL tuning set in parallel with workload replay  STS_CAP_INTERVAL – specifies duration of SQL tuning set capture from cursor cache in seconds

juliandyke.com 36 © Julian Dyke RAT Trap - Synchronization  Most workloads require full synchronization  Failure to synchronize will increase amount of divergence  Potentially invalidates results  Object synchronization may be useful for a limited range of workloads

juliandyke.com 37 © Julian Dyke Synchronization INSERT INTO t ROWS SELECT FROM t ROWS UPDATE t ROWS DELETE FROM t ROWS A B C D 14:3014:4515:0015:1515:30 Capture – Table t contains 0 rows at end of capture Sessions

juliandyke.com 38 © Julian Dyke Synchronization INSERT INTO t ROWS SELECT FROM t 0 ROWS UPDATE t 0 ROWS DELETE FROM t 0 ROWS A B C D 14:3014:4515:0015:1515:30 Replay without synchronization In this example table t contains rows at end of replay Sessions

juliandyke.com 39 © Julian Dyke RAT Trap – Connect and Think Times  Changing connect times and/or think times  Can introduce or alleviate contention  May not be representative of workload  No granularity  Connect / think times must be changed for entire workload  For example cannot distinguish between OLTP and batch within workload  Beware of  Time dependent workload e.g. feeds from other systems  External schedulers e.g. Control M  Application server bottlenecks e.g. Java

juliandyke.com 40 © Julian Dyke Timing A B C D BATCH OLTP 14:3014:4515:0015:1515:30 Sessions Capture – OLTP sessions run at 14:30 and complete by 14:45 Batch runs at 15:00

juliandyke.com 41 © Julian Dyke Timing A B C D BATCH OLTP 14:3014:4515:0015:1515:30 Sessions Replay with connect time set to 0% Batch and OLTP all start at 14:30 – may result in resource contention

juliandyke.com 42 © Julian Dyke RAT Trap – Scaling  RAT offers limited scaling of workloads  For a specific session  SELECT statements can be scaled to multiple sessions  DML statements are only executed in one session  Therefore scaling can only be considered appropriate for read-only workloads  For all other workloads,  Further analysis will be required  Scaling may not be appropriate

juliandyke.com 43 © Julian Dyke Workload Replay Client  Replay client is a multi-threaded program called wrc located in $ORACLE_HOME/bin  Included in Oracle and above client  Each thread submits a workload from a captured session  Database will wait for replay clients to connect before replay begins  Replay clients should run on separate hardware to database  Replay clients must have access to replay directory  Replay directory should contain pre-processed workload capture  Replay directory should be in different file system to database files  Replay client must specify username/password  user must have DBA role  user cannot be SYS

juliandyke.com 44 © Julian Dyke Workload Replay Client - Calibration  Run calibration to determine how many replay clients are required to support the replay workload  For example: wrc ratuser/ratuser MODE=calibrate REPLAYDIR=‘/home/oracle/capture1’;  Advanced parameters are:  PROCESS_PER_CPU - Maximum number of client process than can be run per CPU (Default: 4)  THREADS_PER_PROCESS - Maximum number of threads than can be run within a client process (Default: 50)

juliandyke.com 45 © Julian Dyke Workload Replay Client - Calibration  Sample output: Workload Replay Client: Release Production on Thu May 24 20:01: Report for Workload in: /home/oracle/rat/capture31 Recommendation: Consider using at least 2 clients divided among 1 CPU(s) You will need at least 135 MB of memory per client process. If your machine(s) cannot match that number, consider using more clients. Workload Characteristics: - max concurrency: 71 sessions - total number of sessions: Assumptions: - 1 client process per 50 concurrent session - 4 client process per CPU KB of memory cache per concurrent session - think time scale = connect time scale = synchronization = TRUE

juliandyke.com 46 © Julian Dyke Workload Replay Client - Replay  To replay the workload specify the REPLAY mode  For example: wrc ratuser/ratuser MODE=replay REPLAYDIR=‘/home/oracle/capture1’  Options include:  WORKDIR – directory for trace files  DEBUG – ON or OFF (Default : OFF)  CONNECTION_OVERRIDE – If TRUE the ignore replay connections specified in DBA_WORKLOAD_CONNECTION_MAP. If FALSE (default) use replay connections in DBA_WORKLOAD_CONNECTION_MAP  SERIALIZE_CONNECTS – if TRUE all replay threads will connect to database serially (one after another). Recommended for clients using bequeath protocol. If FALSE (default) replay threads will connect to database concurrently  DSCN_OFF – If TRUE then ignore all dependencies due to block contention during capture when synchronizing replay. If FALSE (default) honour all captured dependencies

juliandyke.com 47 © Julian Dyke Starting a Workload Replay  After the replay clients have been started, the replay must be started on the database BEGIN dbms_workload_replay.start_replay; END;  The START_REPLAY procedure does not take any arguments  When executed within SQL*Plus,  session returns to the prompt after replay has been started  replay continues to execute in background

juliandyke.com 48 © Julian Dyke Workload Replay Directories  The replay creates a new replay directory within the capture directory  For example if the capture directory is /home/oracle/rat/capture31:  /home/oracle/rat/capture31/rep  The replay directory name includes the REPLAY_DIR_NUMBER which is reported in DBA_WORKLOAD_REPLAYS SELECT replay_dir_number FROM dba_workload_replays WHERE id = 31; REPLAY_DIR_NUMBER  The workload replay creates several files within the replay directory:  wcr_replay.wmd- Replay workload metadata  wcr_rep_uc_graph_ extb- Replay user calls graph  wcr_rr_ xml- Replay report – XML format

juliandyke.com 49 © Julian Dyke Managing a Workload Replay  To pause a workload replay use: EXECUTE dbms_workload_replay.pause_replay;  To resume a paused workload replay use: EXECUTE dbms_workload_replay.resume_replay;  To check if a replay is paused use: SELECT dbms_workload_replay.is_replay_paused FROM dual;  To cancel a workload replay use: EXECUTE dbms_workload_replay.cancel_replay;

juliandyke.com 50 © Julian Dyke Exporting AWR Data  AWR data  can be exported to provide detailed workload analysis  is also required for AWR Compare Period report  To export AWR use the EXPORT_AWR procedure e.g: EXECUTE dbms_workload_replay.export_awr (replay_id=>107);/ AWR snapshots are required for subsequent reporting Ensure that the AWR snapshots are exported before they exceed the AWR retention period and are automatically deleted  Replay AWR data is exported into the replay directory, for example:  /home/oracle/rat/capture31/rep  The export files include the REPLAY_DIR_NUMBER:  wcr_ra_ dmp  wcr_ra_ log

juliandyke.com 51 © Julian Dyke Generating a Replay Report  Identify the most recent replay ID SELECT MAX(id) AS id FROM dba_workload_replays WHERE status = 'COMPLETED'; ID 2  Generate the replay report SET SERVEROUTPUT ON DECLARE l_clobCLOB BEGIN l_clob := dbms_workload_replay.report ( replay_id=>1, format => DBMS_WORKLOAD_REPLAY.TYPE_TEXT ); DBMS_OUTPUT.PUT_LINE (l_clob); END; /

juliandyke.com 52 © Julian Dyke Generating a Replay Report  The replay report format can be:  DBMS_WORKLOAD_REPLAY.TYPE_TEXT  DBMS_WORKLOAD_REPLAY.TYPE_HTML  DBMS_WORKLOAD_REPLAY.TYPE_XML  The AWR snapshots must still exist in the replay database to generate the replay report  The replay report includes the following:  Details of workload replay including name, filters, date and time  Replay options and number of replay clients started  Overall statistics about the replay and capture including total DB time, number of logins, number of transactions  Profile of replayed workload  Replay divergence  Error divergence  DML and SQL query data divergence

juliandyke.com 53 © Julian Dyke Divergence  When a workload is replayed there can be divergence between the capture and the replay  There are two types of divergence  Performance Divergence – occurs when changes on the replay system affect overall performance. Changes may include  Software  Hardware  Parameters  Data Divergence – occurs when results of DML or SQL queries do not match  For example a SELECT statement may return fewer rows during replay than during capture

juliandyke.com 54 © Julian Dyke Listing Divergences  Divergences are reported in DBA_WORKLOAD_REPLAY_DIVERGENCE  Each divergence is identified by  REPLAY_ID  STREAM_ID  CALL_COUNTER  Information about a divergence is reported by the GET_DIVERGING_STATEMENT procedure in DBMS_WORKLOAD_REPLAY

juliandyke.com 55 © Julian Dyke RAT Trap – PLSQL Blocks  Anonymous PL/SQL blocks are captured  PL/SQL calls within those blocks are not captured  SQL statement calls within those blocks are not captured  Only errors returned by PL/SQL block exceptions are recorded  If recursive exceptions are caught and handled internally these will not be reported  If PL/SQL logic is different, this may not be captured  Replay may be affected by  Changes in supplied PL/SQL packages  Changes in application PL/SQL packages

juliandyke.com 56 © Julian Dyke Replay Analysis  The following types of reports are available to analyse workload capture and replay:  Capture Report  Replay Report  Compare Period Report  Compare SQLSET report

juliandyke.com 57 © Julian Dyke Importing a Capture AWR  Before running the compare reports, it is necessary to import the capture AWR  The workload analyzer attempts to import the capture AWR, but this version does not appear to be usable  The capture AWR should be imported into a new schema.  In this example the new schema is called CAPTURE31  RESOURCE role appears to be necessary and sufficient CREATE USER capture31 IDENTIFIED BY capture31; GRANT RESOURCE TO capture31;  Identify the ID of the capture workload SELECT id FROM dba_workload_captures WHERE name = ‘CAPTURE31’; ID 115

juliandyke.com 58 © Julian Dyke Importing a Capture AWR  Import the AWR using the IMPORT_AWR procedure. For example: SET SERVEROUTPUT ON DECLARE l_dbid NUMBER; BEGIN l_dbid := dbms_workload_capture.import_awr ( capture_id => 115, staging_schema => 'CAPTURE31‘ ); dbms_output.put_line (‘DBID = '||l_dbid); END; / DBID =  The IMPORT_AWR function returns the new DBID assigned to the imported AWR.

juliandyke.com 59 © Julian Dyke Compare Period Reports  Compare Period reports allow comparison of  Workload replay with workload capture  Workload replay with another workload replay from same capture  Only workload replays containing at least 5 minutes of database time can be compared using this report

juliandyke.com 60 © Julian Dyke Compare Period Reports  For example: SET PAGESIZE 0 SET TRIMSPOOL ON SET LINESIZE 500 SET FEEDBACK OFF SET LONG SET SERVEROUTPUT ON VAR v_clob CLOB BEGIN dbms_workload_replay.compare_period_report ( replay_id1 => 31, replay_id2 => NULL, format => DBMS_WORKLOAD_REPLAY.TYPE_HTML, result => :v_clob ); END; / PRINT v_clob

juliandyke.com 61 © Julian Dyke RAT Trap – DB Time  DB time is the best and possibly only metric to compare captures with replays  Other metrics can be used to compare replays with each other  DB time may be affected by  Changes in hardware e.g.  SSD,  10GbE networks  faster CPU  more memory  Changes in Oracle version  Additional functionality  Longer code paths  Background workload  Divergence  Make sure you understand all the differences between environments before making a decision based on Database Replay outcomes

juliandyke.com 62 © Julian Dyke Compare SQLSET Reports  SQL Performance Analyzer (SPA) reports can be generated using the DBMS_WORKLOAD_REPLAY package  The SPA can be used to compare  a SQL tuning set from a workload replay with the SQL tuning set from the workload capture  a SQL tuning set from a workload replay with the SQL tuning set from another workload replay from the same workload capture

juliandyke.com 63 © Julian Dyke Compare SQLSET Report SET PAGESIZE 0 SET TRIMSPOOL ON SET LINESIZE 500 SET FEEDBACK OFF SET LONG VAR v_clob CLOB DECLARE l_result VARCHAR2(200); BEGIN l_result := dbms_workload_replay.compare_sqlset_report ( replay_id1 => 44, replay_id2 => NULL, format => DBMS_WORKLOAD_REPLAY.TYPE_HTML, result => :v_clob ); END; / PRINT v_clob SPOOL OFF Compare replay with original capture

juliandyke.com 64 © Julian Dyke Compare SQLSET Report SET PAGESIZE 0 SET TRIMSPOOL ON SET LINESIZE 500 SET FEEDBACK OFF SET LONG VAR v_clob CLOB DECLARE l_result VARCHAR2(200); BEGIN l_result := dbms_workload_replay.compare_sqlset_report ( replay_id1 => 44, replay_id2 => 42, format => DBMS_WORKLOAD_REPLAY.TYPE_HTML, result => :v_clob ); END; / PRINT v_clob SPOOL OFF Compare replay with another replay

juliandyke.com 65 © Julian Dyke Conclusions  RAT can be very good at capturing and replaying workloads  Requires a lot of user discipline  Follow the capture and replay recommendations  Unsupported workload features can increase divergence  For best results avoid using “enhancements” such as  Object synchronization  Connect time modifications  Think time modifications  Workload scaling

juliandyke.com 66 © Julian Dyke Acknowledgements  This presentation would not have been possible without the help of:  Andrew Ashworth (Ash)  Pete Taylor  Thank you