Hidden Features You Probably Don t Know About And Are FREE. Graham Wood Oracle Corp

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1 Hidden Features You Probably Don t Know About And Are FREE Graham Wood Oracle Corp

2 Features You Probably Don t Know About And Are MOSTLY FREE

3 1977 Oracle Database 30 Years of Sustained Innovation Database Vault Transparent Data Encryption Grid Computing Self Managing Database XML Database Oracle Data Guard Real Application Clusters Flashback Query Virtual Private Database Built in Java VM Partitioning Support Built in Messaging Object Relational Support Multimedia Support Data Warehousing Optimizations Parallel Operations Distributed SQL & Transaction Support Cluster and MPP Support Multi-version Read Consistency Client/Server Support Platform Portability Commercial SQL Implementation 2007

4 SQL trace 4

5 DBMS_MONITOR.SESSION_TRACE_ENABLE( session_id IN BINARY_INTEGER DEFAULT NULL, serial_num IN BINARY_INTEGER DEFAULT NULL, waits IN BOOLEAN DEFAULT TRUE, binds plan_stat IN BOOLEAN DEFAULT FALSE, IN VARCHAR2 DEFAULT NULL); 5

6 DBMS_MONITOR.SESSION_TRACE_ENABLE( session_id IN BINARY_INTEGER DEFAULT NULL, serial_num IN BINARY_INTEGER DEFAULT NULL, waits IN BOOLEAN DEFAULT TRUE, binds plan_stat IN BOOLEAN DEFAULT FALSE, IN VARCHAR2 DEFAULT NULL); Frequency at which we dump row source statistics. Value should be 'NEVER', 'FIRST_EXECUTION' (equivalent to NULL) or 'ALL_EXECUTIONS'. 6

7 SQL trace Enabling Capture row source data for more executions Trace file contents CLOSE statements captured Previously this was missing time Cursor mapping broken (11gR1) Statement text printed on every execute Long cursor numbers (11gR2) Not so human readable 7

8 SQL trace Enabling Capture row source data for more executions Trace file contents CLOSE statements captured Previously this was missing time Cursor mapping broken (11gR1) Statement text printed on every execute Long cursor numbers (11gR2) Tkprof enhancements Prints SQL id and plan hash for each statement Reports First, Avg, Max from multiple row source dumps 8

9 SQL trace Enabling Capture row source data for more executions Trace file contents CLOSE statements captured Previously this was missing time Cursor mapping broken (11gR1) Statement text printed on every execute Long cursor numbers (11gR2) Tkprof enhancements Prints SQL id and plan hash for each statement Reports First, Avg, Max from multiple row source dumps But not CLOSE doh! 9

10 SQL trace Enabling trace for individual SQL statements alter session set events 'sql_trace [sql: g3yc1js3g2689 7ujay4u33g337]' 10

11 SQL Getting SQL info without making problem worse V$SQLstat 11

12 SQL Get outline data for a single statement SELECT * FROM table ( DBMS_XPLAN.DISPLAY_CURSOR ('atfwcg8anrykp', NULL, ADVANCED')); Get Estimated and Actual rows SELECT * FROM table ( DBMS_XPLAN.DISPLAY_CURSOR (FORMAT=>'ALLSTATS LAST')); 12

13 SELECT /*+ gather_plan_statistics */ p.prod_name, SUM(s.quantity_sold) FROM sales s, products p WHERE s.prod_id =p.prod_id GROUP By p.prod_name ; SELECT * FROM table ( DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST'));

14 SQL Set a parameter for running an individual statement OPT_PARAM hint SELECT /*+ OPT_PARAM('star_transformation_enabled,'true') */ * FROM.. 14

15 SQL Cause all statements to run without hints _optimizer_ignore_hints=true Extremely useful for testing 15

16 Optimizer Statistics Pending Statistics Separates stats collection from stats publishing Capture stats as Pending Test using pending stats Publish once verified 16

17 Pending Statistics Controlled by parameter optimizer_use_pending_statistics Determines if the optimizer will use pending statistics Set to false by default in 11gR1 Set at session level for testing Use dbms_stats package set_table_prefs All tables preferences have publish set to true by default publish_private_stats Once stats have been tested publish them for general use Monitor Look at dictionary table user_*_pending_stats (* = tab, col, ind)

18 Optimizer Statistics Pending Statistics Separates stats collection from stats publishing Capture stats as Pending Test using pending stats Publish once verified Setting Statistics Use dbms_stats.set_*_stats Very useful for min/max values Be careful! 18

19 Setting Statistics declare minmax dbms_stats.numarray; da dbms_stats.datearray; sr dbms_stats.statrec; begin /* prepare min/max values */ /* date type column example */ da := dbms_stats.datearray (to_date('01/01/1999','mm/dd/yyyy'),sysdate); sr.epc := 2; sr.bkvals := null; dbms_stats.prepare_column_values(sr, da); dbms_stats.set_column_stats('scott','emp','hiredate',srec=>sr); end; /

20 More Analytics Long awaited LISTAGG And many more.

21 Analytics SQL> select deptno, 2 listagg( ename, '; ' ) 3 within group 4 (order by ename) enames 5 from emp 6 group by deptno 7 order by deptno 8 / DEPTNO ENAMES CLARK; KING; MILLER 20 ADAMS; FORD; JONES; SCOTT; SMITH 30 ALLEN; BLAKE; JAMES; MARTIN; TURNER; WARD

22 Analytics SQL> select deptno, 2 ename, 3 row_number() 4 over (partition by deptno 5 order by ename) rn, 6 first_value(ename) 7 over (partition by deptno 8 order by ename) "1st ename", 9 nth_value(ename,3) 10 over (partition by deptno 11 order by ename) "3rd ename", 12 last_value(ename) 13 over (partition by deptno 14 order by ename 15 rows between current row 16 and unbounded following) "last ename" 17 from emp 18 order by deptno, ename 19 /

23 Analytics SQL> select deptno, 2 ename, 3 row_number() 4 over (partition by deptno 5 order by ename) rn, 6 first_value(ename) 7 over (partition by deptno 8 order by ename) "1st ename", 9 nth_value(ename,3) 10 over (partition by deptno 11 order by ename) "3rd ename", 12 last_value(ename) 13 over (partition by deptno 14 order by ename 15 rows between current row 16 and unbounded following) "last ename" 17 from emp 18 order by deptno, ename 19 / DEPTNO ENAME RN 1st e 3rd ena last en CLARK 1 CLARK MILLER KING 2 CLARK MILLER MILLER 3 CLARK MILLER MILLER 20 ADAMS 1 ADAMS SMITH FORD 2 ADAMS SMITH JONES 3 ADAMS JONES SMITH SCOTT 4 ADAMS JONES SMITH SMITH 5 ADAMS JONES SMITH 30 ALLEN 1 ALLEN WARD BLAKE 2 ALLEN WARD JAMES 3 ALLEN JAMES WARD MARTIN 4 ALLEN JAMES WARD TURNER 5 ALLEN JAMES WARD WARD 6 ALLEN JAMES WARD

24 External tables allow for a preprocessor Program is run when you SELECT from external table The location is passed to the script/executable The executable does whatever it wants and writes to stdout Stdout is treated as the input file Most common use: gzip

25 External Table Preprocessor SQL> CREATE TABLE EMP_ET 2 ( 3 "EMPNO" NUMBER(4), 4 "ENAME" VARCHAR2(10), 5 "JOB" VARCHAR2(9), 6 "MGR" NUMBER(4), 7 "HIREDATE" DATE, 8 "SAL" NUMBER(7,2), 9 "COMM" NUMBER(7,2), 10 "DEPTNO" NUMBER(2) 11 ) 12 ORGANIZATION external 13 ( TYPE oracle_loader 14 DEFAULT DIRECTORY load_dir 15 ACCESS PARAMETERS 16 ( RECORDS DELIMITED BY NEWLINE 17 preprocessor exec_dir:'run_gunzip.sh' 18 FIELDS TERMINATED BY " " LDRTRIM 19 ) 20 location ( 'emp.dat.gz') 21 ) 22 / Table created.

26 External Table Preprocessor SQL>!file emp.dat.gz emp.dat.gz: gzip compressed data, was "emp.dat", from Unix, last modified: Wed Oct 7 12:48: SQL>!cat run_gunzip.sh #!/bin/bash /usr/bin/gunzip -c $* SQL> select empno, ename from emp_et where rownum <= 5; EMPNO ENAME SMITH 7499 ALLEN 7521 WARD 7566 JONES 7654 MARTIN

27 Other stuff Out of line upgrade Full install rather than upgrade of $ORACLE_HOME

28 Other stuff Connecting to a Hung Database Primarily to get diagnostic etc Sqlplus prelim / as sysdba 28

29 Not FREE, unless you have the correct options

30 SQL Change number of SQL captured by AWR dbms_workload_repository.modify_snapshot_settings (topnsql=> 200) 30

31 SQL Always capture a statement even if not high load dbms_workload_repository.add_colored_sql(:sql_id) 31

32 Reporting AWR SQL Report Report history of execution of a SQL statement Plans in use during different time periods AWR Diff Report Highlights differences between two periods of AWR data AWR RAC Report Reports on distribution of workload across instances ASH Report Any time period Instance or filtered Filtering at sessions level almost equivalent of SQL trace 32

33 Reporting AWR SQL Report Report history of execution of a SQL statement Plans in use during different time periods AWR Diff Report Highlights differences between two periods of AWR data AWR RAC Report Reports on distribution of workload across instances ASH Report Any time period Instance or filtered Filtering at sessions level almost equivalent of SQL trace AND DON T FORGET THE ADDM REPORT! 33

34 Reporting See ASH data in EM SQL Monitor 34

35 See Raw ASH data for Session in EM

36 Check Cardinality using SQL Monitor SQL Monitor allows you to compare the estimated number of rows returned for each operation in the plan to actual rows returned

37 Dumping ASH to file Sqlplus prelim / as sysdba >oradebug setmypid >oradebug dump ashdump 10 >alter session set events 'immediate trace name ashdump level 10'; 10 ==> minutes of history you want to dump Generated file can be loaded into database (or Excel)

38 Dumping ASH to file (normal operation) Sqlplus / as sysdba >create table my_ash_data as select * from v$active_session_history; exp my_ash_data Load into another database Run custom queries

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41 For More Information oracle database 11g or