AWR dbms_xplan

7/28/2019 AWR dbms_xplan

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dbms_xplan:A Swiss army knife for performance engineers

Sahil Thapar

Riyaj Shamsudeen


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Disclaimer

These slides and materials represent the work and opinions of the author and do

not constitute official positions of my current or past employer or any other

organization. This material has been peer reviewed, but author assume no

responsibility whatsoever for the test cases.

If you corrupt your databases by running my scripts, you are solely responsible

for that.


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Options

EXPLAIN PLAN

(Version 7 or older)

AUTOTRACE (Version 8i +)

SQL_TRACE (Version 7)

DBMS_XPLAN

Estimated, not always reliable

Actual plan; but must enable trace before the run.

Actual plan, after the run, always available.

Actual plan, buggy.


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PARSING IN CURSOR #1844674 len=1000 dep=0 uid=173 oct=3 lid=173 tim=7861072491388hv=2701626457 ad='498d8f1d0' sqlid='9sup9gfhhg32t'SELECT RECID, TABLENAME, PROJECT_NUMBER, PROJECT_NAME, CARRYING_OUT_ORGANIZATION,...FROM ( SELECT STGTBL_RECID

...WHERE PROCESSED_FLAG='U' ) ORDER BY TABLENAME, CREATION_DATEPARSE:#1844674:c=10000,e=10162,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,plh=3298327531,tim=7861072491386EXEC:#1844674:c=0,e=139,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,plh=3298327531,tim=786107249172

3EXEC:#1844674:c=0,e=139,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,plh=3298327531,tim=7861072491723

..WAIT #1844674: nam='Disk file operations I/O' ela= 2013 FileOperation=2 fileno=811filetype=2 obj#=706379 tim=786107FETCH#1844674:c=18020000,e=59603730,p=199262,cr=199331,cu=0,mis=0,r=0,dep=0,og=1,plh=3298327531,tim=7861

STAT #1844674 id=3 cnt=0 pid=2 pos=1 obj=0 op='SORT UNIQUE (cr=199331 pr=199262 pw=0

time=59603707 us cost=56817 size=126622640 card=2146146)'STAT #1844674 id=4 cnt=0 pid=3 pos=1 obj=0 op='UNION-ALL (cr=199331 pr=199262 pw=0time=59603638 us)'

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Raw trace file

Content of a sql trace file:


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tkprof (1)

SELECT RECID, TABLENAME, PROJECT_NUMBER, PROJECT_NAME, CARRYING_OUT_ORGANIZATION,COMPANY,

CHARGEABLE_FLAG, START_DATE, END_DATE, CREATION_DATE, LAST_UPDATE_DATE,PROCESSED_FLAG,

.

..WHERE PROCESSED_FLAG='U' ) ORDER BY TABLENAME, CREATION_DATE

call count cpu elapsed disk query current rows

------- ------ -------- ---------- ---------- ---------- ---------- ----------Parse 1 0.01 0.01 0 0 0 0Execute 1 0.00 0.00 0 0 0 0

Fetch 1 18.02 59.60 199262 199331 0 0------- ------ -------- ---------- ---------- ---------- ---------- ----------

total 3 18.03 59.61 199262 199331 0 0


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tkprof (2)

Rows (max) Row Source Operation---------- ---------------------------------------------------

0 SORT ORDER BY (cr=199331 pr=199262 pw=0 time=59603767us cost=180933size=641697654 card=2146146)

0 VIEW (cr=199331 pr=199262 pw=0 time=59603722 us cost=56817 size=641697654card=2146146)

0 SORT UNIQUE (cr=199331 pr=199262 pw=0 time=59603707 us cost=56817size=126622640 card=2146146)0 UNION-ALL (cr=199331 pr=199262 pw=0 time=59603638 us)

0 TABLE ACCESS FULL ORD_AP_IF_PROJECTS (cr=46025 pr=45963 pw=0time=17088312 us cost=6568 size=85 card=1)

0 TABLE ACCESS FULL ORD_AP_IF_TASKS (cr=153306 pr=153299 pw=0

time=42515291 us cost=21894 size=126622555

Elapsed times include waiting on following events:

Event waited on Times Max. Wait Total Waited---------------------------------------- Waited ---------- ------------SQL*Net message to client 1 0.00 0.00

Disk file operations I/O 129 0.01 0.26


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Usage

Displays execution plan stored in three different places

1) PLAN_TABLEdbms_xplan.diplay(estimated plan)

2) SGA of instancedbms_xplan.display_cursor(real plan from memory)

3) AWRdbms_xplan.display_awr(real,history plan from AWR)


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Comparison

Sl Tkprof Dbms_xplan

1 Trace must be enabled. Basic statistics are available inmemory and AWR

2 CBO notes are not visible Note section is very useful

3 No predicate Predicates printed from memory.

4 Bind values can be retrieved withease

5 Plan history can be retrievedeasily.


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dbms_xplan format arguments

Class level alias bytes cost note predicateparallel partition projection outlines peeked_bindsremote rowsBASIC

null X X X X XTYPICAL X X X X X X X XSERIAL X X X X X XALL X X X X X X X X X X XADVANCED X X X X X X X X X X X X

Format

select*fromtable(dbms_xplan.display_cursor( sql_id,child_number,format));Examples:select * from table( dbms_xplan.display_cursor());select * from table ( dbms_xplan.display_cursor (null,null, 'ADVANCED'));select * from table ( dbms_xplan.display_cursor ('811a0zb26fw0x',0, 'BASIC'));select * from table ( dbms_xplan.display_cursor ('811a0zb26fw0x',0, ALL -projection'));select * from table ( dbms_xplan.display_cursor ('811a0zb26fw0x',0, ALL +peeked_binds'));Formatarguments:

'ADVANCED''PREDICATE'

'PREDICATE+OUTLINE'

FormatargumentscombinaKon:TYPICAL is the default class


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SQL_ID 9sup9gfhhg32t, child number 0-------------------------------------SELECT RECID, TABLENAME, PROJECT_NUMBER, PROJECT_NAME,

LEDIT_CLASS_CODE, ALC, FRC FROM CCW_PA_IF_TASKS WHERE PROCESSED_FLAG='U') ORDER BY TABLENAME, CREATION_DATE

Plan hash value: 3298327531

---------------------------------------------------------------------------------------------------| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |----------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | | | | 180K(100)| || 1 | SORT ORDER BY | | 2146K| 611M| 698M| 180K (5)| 00:09:03 |

| 2 | VIEW | | 2146K| 611M| | 56817 (10)| 00:02:51 |

| 3 | SORT UNIQUE | | 2146K| 120M| 172M| 56817 (91)| 00:02:51 || 4 | UNION-ALL | | | | | | ||* 5 | TABLE ACCESS FULL| ORD_AP_IF_PROJECTS | 1 | 85 | | 6568 (14)| 00:00:20 ||* 6 | TABLE ACCESS FULL| ORD_AP_IF_TASKS | 2146K| 120M| | 21894 (14)| 00:01:06 |

----------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):---------------------------------------------------

5 - filter("PROCESSED_FLAG"='U')6 - filter("PROCESSED_FLAG"='U')

Note-----

- SQL profile not used for this statement

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dbms_xplan.display

Optimizer estimates


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Display_cursor

select * from table(dbms_xplan.display_cursor('9yx90c0nwv9tk',0,'allstats'));

SQL_ID 9yx90c0nwv9tk, child number 0-------------------------------------

SELECT /* gather_plan_statistics */ RECID, TABLENAME,...

Plan hash value: 3298327531---------------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads |

---------------------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | | 0 |00:00:32.50 | 199K| 199K|

| 1 | SORT ORDER BY | | 1 | 2146K| 0 |00:00:32.50 | 199K| 199K|

| 2 | VIEW | | 1 | 2146K| 0 |00:00:32.50 | 199K| 199K|

| 3 | SORT UNIQUE | | 1 | 2146K| 0 |00:00:32.50 | 199K| 199K|| 4 | UNION-ALL | | 1 | | 0 |00:00:32.50 | 199K| 199K||* 5 | TABLE ACCESS FULL| ORD_AP_IF_PROJECTS | 1 | 1 | 0 |00:00:07.90 | 46025 | 45963 |

|* 6 | TABLE ACCESS FULL| ORD_AP_IF_TASKS | 1 | 2146K| 0 |00:00:24.60 | 153K| 153K|

---------------------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):---------------------------------------------------5 - filter("PROCESSED_FLAG"='U')

6 - filter("PROCESSED_FLAG"='U')

Note, output formatted to fit screen


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Easily quantify the solution given..

select * from table(dbms_xplan.display_cursor('9yx90c0nwv9tk',0,'allstats'));Plan hash value: 932773089

----------------------------------------------------------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | OMem | 1Mem | Used-Mem |

----------------------------------------------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | | 0 |00:00:00.01 | 6 | | | || 1 | SORT ORDER BY | | 1 | 2146K| 0 |00:00:00.01 | 6 | 1024 | 1024 | |

| 2 | VIEW | | 1 | 2146K| 0 |00:00:00.01 | 6 | | | || 3 | SORT UNIQUE | | 1 | 2146K| 0 |00:00:00.01 | 6 | 1024 | 1024 | |

| 4 | UNION-ALL | | 1 | | 0 |00:00:00.01 | 6 | | | |

| 5 | TABLE ACCESS BY INDEX ROWID| ORD_PA_IF_PROJECTS | 1 | 1 | 0 |00:00:00.01 | 3 | | | ||* 6 | INDEX RANGE SCAN | ORD_PA_IF_PROJECTS_N1 | 1 | 1 | 0 |00:00:00.01 | 3 | | | |

| 7 | TABLE ACCESS BY INDEX ROWID| ORD_PA_IF_TASKS | 1 | 2146K| 0 |00:00:00.01 | 3 | | | ||* 8 | INDEX RANGE SCAN | ORD_PA_IF_TASKS_N1 | 1 | 2173K| 0 |00:00:00.01 | 3 | | | |

----------------------------------------------------------------------------------------------------------------------------------------------


6 - access("PROCESSED_FLAG"='U')


Note-----


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Privileges

For dbms_xplan.display_awrgrant select on dba_hist_sqltext to scottgrant select on dba_hist_sql_plan to scott;

grant select on v_$database to scott;ORSELECT_CATALOGrole

Privileges needed to execute dbms_xplan

For dbms_xplan.display_cursorgrant select on v_$session to scott;grant select on v_$SQL_PLAN_STATISTICS_ALL to scott;grant select on v_$sql to scott;

grant select on v_$sql_plan to scott;ORSELECT_CATALOGrole orselect any dictionary system privilege


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Internals of dbms_xplan

select * from (table(dbms_xplan.display_cursor('8gzkcsvw362s3',2,'allstats'));

select /* EXEC_FROM_DBMS_XPLAN */ case when upper(sql_text) like'%DBMS_XPLAN%' then 0 else 1 end case, SQL_ID, child_number

fromv$sql where SQL_ID ='8gzkcsvw362s3' and child_number =2

SELECT /*+ opt_param('parallel_execution_enabled', 'false') */extractvalue(xmlval, '/*/info[@type = "sql_profile"]'), extractvalue(xmlval,'/*/info[@type = "sql_patch"]'), extractvalue(xmlval, '/*/info[@type ="baseline"]'), extractvalue(xmlval, '/*/info[@type = "outline"]'),extractvalue(xmlval, '/*/info[@type = "dynamic_sampling"]'),extractvalue(xmlval, '/*/info[@type = "dop"]'), extractvalue(xmlval,

'/*/info[@type = "dop_reason"]'), extractvalue(xmlval, '/*/info[@type ="queuing_reason"]'), extractvalue(xmlval, '/*/info[@type = "row_shipping"]'), extractvalue(xmlval, '/*/info[@type = "index_size"]'),extractvalue(xmlval, '/*/info[@type = "result_checksum"]'),extractvalue(xmlval, '/*/info[@type = "cardinality_feedback"]'),extractvalue(xmlval, '/*/info[@type = "xml_suboptimal"]'),extractvalue(xmlval,'/*/info[@type = "plan_hash"]')

from(select xmltype(:v_other_xml) xmlval from dual)

SELECT PLAN_TABLE_OUTPUTFROMTABLE(CAST(DBMS_XPLAN.PREPARE_RECORDS(:B1 , :B2 ) ASSYS.DBMS_XPLAN_TYPE_TABLE))

Really complicated recursive SQL statements!


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More internals

SELECT /*+ opt_param('parallel_execution_enabled', 'false') *//* EXEC_FROM_DBMS_XPLAN */ id, position, depth ,

operation, options, object_name, cardinality, bytes, temp_space, cost,io_cost, cpu_cost, time,.

vp.optimal_executions opt_cnt,vp.onepass_executions one_cnt,vp.multipasses_executions multi_cnt,vp.max_tempseg_size max_tmp,vp.last_tempseg_size last_tmpfrom V$SQL_PLAN_STATISTICS_ALL vp, v$sqlwhere vp.SQL_ID = '8gzkcsvw362s3' and vp.child_number=2 and vp.SQL_ID = v$sql.SQL_ID and v$sql.child_number=2)order by id


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How do I tune?

my_sql.sql

Set linesize 300;set pagesize 1000;

--Declare variable and assign valuesvar order_id number;execute :order_id:=53759119SELECT oeh.header_id, oel.line_idFROM oe_order_headers_all oeh, oe_order_lines_all oel

WHERE oeh.header_id = :order_id AND oeh.header_id =oel.header_id

/select * from table(dbms_xplan.DISPLAY_CURSOR(null, null, 'ALLSTATS'))/

Prepare the sql to be run for performance analysis.


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Dos & Donts

Dos1. Current execution plan and runtime statistics are the first

step.

2. Execute a test case first to reproduce.

Dont

1. Try to use same bind type as application uses.- Literal vs bind variables

- number vs varchar2 data type etc2. Try to use format same as the application for your test case.

- CTAS vs INSERT


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PLAN_TABLE_OUTPUTSQL_ID cttafpfjwqjdm, child number 0-------------------------------------select oeh.header_id,oel.line_id from oe_order_headers_all oeh,oe_order_lines_all oel whereoeh.header_id=:order_id and oeh.header_id=oel.header_idPlan hash value: 4180984038---------------------------------------------------------------------------------------------------------------------------| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop

|---------------------------------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | | | 11 (100)| | ||| 1 | NESTED LOOPS | | 6 | 114 | 11 (0)| 00:00:01 | ||| 2 | PARTITION HASH SINGLE | | 1 | 6 | 2 (0)| 00:00:01 | KEY | KEY||* 3 | INDEX UNIQUE SCAN | OE_ORDER_HEADERS_U1 | 1 | 6 | 2 (0)| 00:00:01 | KEY | KEY|| 4 | TABLE ACCESS BY GLOBAL INDEX ROWID| OE_ORDER_LINES_ALL | 6 | 78 | 9 (0)| 00:00:01 | ROWID | ROWID|

|* 5 | INDEX RANGE SCAN | OE_ORDER_LINES_N1 | 6 | | 3 (0)| 00:00:01 | ||---------------------------------------------------------------------------------------------------------------------------

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dbms_xplan.display_cursor


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...Predicate Information (identified by operation id):---------------------------------------------------

3 - access("OEH"."HEADER_ID"=:ORDER_ID)5 - access("OEL"."HEADER_ID"=:ORDER_ID)Note-----

- Warning These are only collected when:* hint 'gather_plan_statistics' is used for the statement or

* parameter 'statistics_level' is set to 'ALL', at session or system level* Cardinality feedback used* Dynamic sampling used

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dbms_xplan.display_cursor ..2


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--------------------------------------------------------------------------------------------------------------------------| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart|Pstop |---------------------------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | | | 11200 (100)| | ||| 1 | NESTED LOOPS | | 6 | 114 | 11 (0)| 00:10:01 | ||| 2 | PARTITION HASH SINGLE | | 1 | 6 | 2 (0)| 00:00:01 | KEY |KEY ||* 3 | INDEX UNIQUE SCAN | OE_ORDER_HEADERS_U1 | 1 | 6 | 2 (0)| 00:00:01 | KEY |KEY ||* 4 | TABLE ACCESS BY GLOBAL INDEX ROWID| OE_ORDER_LINES_ALL | 6 | 78 | 9000 (0)| 00:07:01 | ROWID |ROWID ||* 5 | INDEX RANGE SCAN | OE_ORDER_LINES_N1 | 60000 | | 300 (0)| 00:03:01 | ||------------------------------------------------------------------------------------------------------------------------

---


3 - access("OEH"."HEADER_ID"=:ORDER_ID)4 filter ("OEL".OPEN_FLAG=Y)5 - access("OEL"."HEADER_ID"=:ORDER_ID)

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dbms_xplan: access and filter predicates

Added a predicate oel.open_flag=Y


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Detailed execution statistics

v$sql_plan_statistics_all collects row source level executionstatistics

ROWS

CPU

Physical IO

Logical IO

Elapsed time

To enable at session level set statistics_level=ALL

To enable for all sessions set at system level statistics_level=ALL

To set a SQL statement level add the hint

/*+ gather_plan_statistics */ in the statement.

Setting statistics_level=ALL at system

level can be resource intensive and

should preferably not be enabled in busy

PRODUCTION SYSTEM


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dbms_xplan: script

--my_sql.sql script_nameset linesize 300;set pagesize 1000;

--Declare variable and assign valuesvar order_id number;execute order_id:=53759119

alter session set statistics_level=ALL; --OR ADD HINTSELECT /*+ gather_plan_statistics */ oeh.header_id,oel.line_id

FROM oe_order_headers_all oeh,oe_order_lines_all oelWHERE oeh.header_id = :order_id

AND oeh.header_id = oel.header_id/

Modify the script to enable extended execution statistics


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Execution statistics

SQL_ID 7gftgf917tg2x, child number 0-------------------------------------

select /*+ gather_plan_statistics */ oeh.header_id,oel.line_id fromoe_order_headers_all oeh,oe_order_lines_all oel where

oeh.header_id=:order_id and oeh.header_id=oel.header_id


------------------------------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads |

------------------------------------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | | 4 |00:00:00.03 | 12 | 11 |

| 1 | NESTED LOOPS | | 1 | 6 | 4 |00:00:00.03 | 12 | 11 |

| 2 | PARTITION HASH SINGLE | | 1 | 1 | 1 |00:00:00.01 | 3 | 3 |

|* 3 | INDEX UNIQUE SCAN | OE_ORDER_HEADERS_U1 | 1 | 1 | 1 |00:00:00.01 | 3 | 3 || 4 | TABLE ACCESS BY GLOBAL INDEX ROWID| OE_ORDER_LINES_ALL | 1 | 6 | 4 |00:00:00.02 | 9 | 8 ||* 5 | INDEX RANGE SCAN | OE_ORDER_LINES_N1 | 1 | 6 | 4 |00:00:00.01 | 5 | 4 |

------------------------------------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):

---------------------------------------------------

3 - access("OEH"."HEADER_ID"=:ORDER_ID)5 - access("OEL"."HEADER_ID"=:ORDER_ID)

25 rows selected.

select * from table(dbms_xplan.DISPLAY_CURSOR(null, null, 'ALLSTATS LAST'))/


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Alias

select * from table(dbms_xplan.DISPLAY_CURSOR(null, null, 'ALLSTATS LAST +alias -predicate'));

SELECT /*+ gather_plan_statistics */ oel.line_id FROMoe_order_lines_all oel WHERE oel.open_flag = 'Y' andexists (select 1 from oe_order_headers_all oeh whereoeh.header_id = oel.header_id and oeh.open_flag='Y'

and oeh.last_update_date > sysdate -5)

Plan hash value: 746840967--------------------------------------------------------------------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | OMem | 1Mem | Used-Mem |

--------------------------------------------------------------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | | 3 |00:00:00.01 | 16 | | | |

| 1 | NESTED LOOPS | | 1 | | 3 |00:00:00.01 | 16 | | | || 2 | NESTED LOOPS | | 1 | 1 | 3 |00:00:00.01 | 10 | | | || 3 | SORT UNIQUE | | 1 | 1 | 1 |00:00:00.01 | 5 | 2048 | 2048 | 2048 (0)|

| 4 | TABLE ACCESS BY GLOBAL INDEX ROWID| OE_ORDER_HEADERS_ALL | 1 | 1 | 1 |00:00:00.01 | 5 | | | || 5 | INDEX RANGE SCAN | CCW_OE_ORD_HEADERS_ALL_D1 | 1 | 7 | 1 |00:00:00.01 | 4 | | | |

| 6 | INDEX RANGE SCAN | OE_ORDER_LINES_N1 | 1 | 6 | 3 |00:00:00.01 | 5 | | | || 7 | TABLE ACCESS BY GLOBAL INDEX ROWID | OE_ORDER_LINES_ALL | 3 | 1 | 3 |00:00:00.01 | 6 | | | |--------------------------------------------------------------------------------------------------------------------------------------------------------

Query Block Name / Object Alias (identified by operation id):-------------------------------------------------------------

1 - SEL$5DA710D34 - SEL$5DA710D3 / OEH@SEL$25 - SEL$5DA710D3 / OEH@SEL$26 - SEL$5DA710D3 / OEL@SEL$17 - SEL$5DA710D3 / OEL@SEL$1


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SQL_ID cu2f3xhzy75vc, child number 0-------------------------------------

SELECT /*+ gather_plan_statisticsqb_name(outer_block) */oel.line_idFROM oe_order_lines_all oelWHERE

oel.open_flag = 'Y'and exists(select /*+ qb_name(innner_block) */1 from oe_order_headers_all

oehwhere oeh.header_id = oel.header_id

and oeh.open_flag='Y'and oeh.last_update_date > sysdate -5);

Plan hash value: 746840967--------------------------------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | ..|

--------------------------------------------------------------------------------------------------------------------..| 0 | SELECT STATEMENT | | 1 | | 3 |00:00:00.01 |

Query Block Name / Object Alias (identified by operation id):-------------------------------------------------------------

1 - SEL$8E94A21F4 - SEL$8E94A21F / OEH@INNNER_BLOCK5 - SEL$8E94A21F / OEH@INNNER_BLOCK6 - SEL$8E94A21F / OEL@OUTER_BLOCK7 - SEL$8E94A21F / OEL@OUTER_BLOCK

25

Query Block name


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Default QB Name

Prefix Row Source operation

CRI$ Create index statement

DEL$ DELETE statement

INS$ Insert Statement

MISC$ Miesc SQL like lock table

MRG$ Merge Statement

SEL$ SELECT statement

SET$ Set operators

UPD$ Update statement


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Hints or Outlines

set linesize 300set pagesize 300alter session set statistics_level='ALL';SELECT /* outline query */

RECID, ALC, FRC

...FROM ORD_AP_IF_TASK WHERE PROCESSED_FLAG = 'U')ORDER BY TABLENAME, CREATION_DATE;

select * from table(

dbms_xplan.display_cursor

(null,null,'ALLSTATS LAST +outline'))/


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Outline Data-------------

/*+BEGIN_OUTLINE_DATA

IGNORE_OPTIM_EMBEDDED_HINTSOPTIMIZER_FEATURES_ENABLE('11.2.0.2')OPT_PARAM('_b_tree_bitmap_plans' 'false')

OPT_PARAM('_fast_full_scan_enabled' 'false')ALL_ROWS

OUTLINE_LEAF(@"SEL$2")OUTLINE_LEAF(@"SEL$1")FULL(@"SEL$3" "ORD_AP_IF_TASKS"@"SEL$3")INDEX_RS_ASC(@"SEL$2" "ORD_AP_IF_PROJECTS"@"SEL$2

("ORD_AP_IF_PROJECTS"."PROCESSED_FLAG"))END_OUTLINE_DATA

*/

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Outline---------------------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers |

-------------------------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | | 0 |00:00:27.40 |

153K| ..| 1 | SORT ORDER BY | | 1 | 2146K| 0 |00:00:27.40 | 153K|

| 2 | VIEW | | 1 | 2146K| 0 |00:00:27.40 | 153K|

| 3 | SORT UNIQUE | | 1 | 2146K| 0 |00:00:27.40 | 153K| | 4 | UNION-ALL | | 1 | | 0 |00:00:27.40 | 153K|

| 5 | TABLE ACCESS BY INDEX ROWID| ORD_AP_IF_PROJECTS | 1 | 1 | 0 |00:00:00.01 | 3 | | 6 | INDEX RANGE SCAN | ORD_AP_IF_PROJECTS_N1 | 1 | 1 | 0 |00:00:00.01 | 3 |

| 7 | TABLE ACCESS FULL | ORD_AP_IF_TASKS | 1 | 2146K| 0 |00:00:27.40 | 153K|-------------------------------------------------------------------------------------------------------------------


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---------------------------------------------------


7 - filter("PROCESSED_FLAG"='U')

Outline Data

-------------

/*+...

FULL(@"SEL$3" "ORD_AP_IF_TASKS"@"SEL$3")INDEX_RS_ASC(@"SEL$2" "ORD_AP_IF_PROJECTS

"@"SEL$2" ("ORD_AP_IF_PROJECTS"."PROCESSED_FLAG"))

END_OUTLINE_DATA*/

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Tuning SQL

SQLPLUS> select count(1) from ORD_AP_IF_TASKS where PROCESSED_FLAG='U';COUNT(1)

----------0

There is an index on ORD_AP_IF_TASKS.PROCESSED_FLAG


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set linesize 300set pagesize 300alter session set statistics_level='ALL';SELECT/*+

BEGIN_OUTLINE_DATAIGNORE_OPTIM_EMBEDDED_HINTSOPTIMIZER_FEATURES_ENABLE('11.2.0.2')DB_VERSION('11.2.0.2')OPT_PARAM('_b_tree_bitmap_plans' 'false')OPT_PARAM('_fast_full_scan_enabled' 'false')ALL_ROWS

OUTLINE_LEAF(@"SEL$2")OUTLINE_LEAF(@"SEL$3")OUTLINE_LEAF(@"SET$1")OUTLINE_LEAF(@"SEL$1")NO_ACCESS(@"SEL$1" "from$_subquery$_001"@"SEL$1")INDEX_RS_ASC(@"SEL$3" ORD_AP_IF_TASKS"@"SEL$3" (ORD_AP_IF_TASKS"."PROCESSED_FLAG"))INDEX_RS_ASC(@"SEL$2" ORD_AP_IF_PROJECTS"@"SEL$2" (ORD_AP_IF_PROJECTS"."PROCESSED_FLAG"))END_OUTLINE_DATA

*/WHERE PROCESSED_FLAG = 'U')ORDER BY TABLENAME, CREATION_DATE

/select * from table(dbms_xplan.display_cursor(null,null,'ALLSTATS LAST +outline'))/

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Bob the Builder

FULL(@"SEL$3" "ORD_AP_IF_TASKS"@"SEL$3")

Copying outline as hint;

Altering Full Table Scan

to Index Range Scan.


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Tuned Plan---------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time |---------------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | | 0 |00:00:00.01 || 1 | SORT ORDER BY | | 1 | 2146K| 0 |00:00:00.01 || 2 | VIEW | | 1 | 2146K| 0 |00:00:00.01 || 3 | SORT UNIQUE | | 1 | 2146K| 0 |00:00:00.01 || 4 | UNION-ALL | | 1 | | 0 |00:00:00.01 || 5 | TABLE ACCESS BY INDEX ROWID| ORD_AP_IF_PROJECTS | 1 | 1 | 0 |00:00:00.01 ||* 6 | INDEX RANGE SCAN | ORD_AP_IF_PROJECTS_N1 | 1 | 1 | 0 |00:00:00.01 || 7 | TABLE ACCESS BY INDEX ROWID| ORD_AP_IF_TASKS | 1 | 2146K| 0 |00:00:00.01 ||* 8 | INDEX RANGE SCAN | ORD_AP_IF_TASKS_N1 | 1 | 2173K| 0 |00:00:00.01 |---------------------------------------------------------------------------------------------------------

Outline Data-------------/*+

BEGIN_OUTLINE_DATAIGNORE_OPTIM_EMBEDDED_HINTSOPT_PARAM('_b_tree_bitmap_plans' 'false')OPT_PARAM('_fast_full_scan_enabled' 'false')ALL_ROWSOUTLINE_LEAF(@"SEL$1")NO_ACCESS(@"SEL$1" "from$_subquery$_001"@"SEL$1")INDEX_RS_ASC(@"SEL$3" ORD_AP_IF_TASKS"@"SEL$3" (ORD_A__IF_TASKS"."PROCESSED_FLAG"))INDEX_RS_ASC(@"SEL$2" ORD_AP_IF_PROJECTS"@"SEL$2" (ORD_AP_IF_PROJECTS"."PROCESSED_FLAG"))

END_OUTLINE_DATA*/


6 - access("PROCESSED_FLAG"='U')8 - access("PROCESSED_FLAG"='U)


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32

So many details..So little space..Column Description

Always available columnsid Identified of each step in the execution plan; if prefixed with * then predicate information available in predicate section

Operation Row source operation

Name The database object in the operation

CBO parse time information

Rows Estimated number of rows returned by the row source operation; derived from statistics on names object in the operation

Bytes Estimated amount of data returned by the operation

TempSpc The estimated amount of temp space usage by the operation

Cost(%CPU) The estimated cost of the row source operation. The percentage CPU cost is given in () for individual row source operationTime Estimated amount of time needed to execute that operation in HH:MM:SS

Partitioning

Pstart Number of first partition to be accessed

Pstop The number of last partition to be accessed

Parallel Processing

TQ Table queue used for processing

IN-OUT The relation between parallel operations

PQ Distrib The distribution used by producers to send data to consumersRuntime Statistics

Starts The number of times operation was executed (check more nested loop joins operation)

A-Rows Actual number of rows returned

A-Time Actual amount of time spent executing the operation

I/O Statistics

Buffers Logical reads operations performed during execution of each step

Read Physical reads performed for each operation

Write Physical writes performed


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33

dbms_xplan.display_awr

Format

select*fromtable(dbms_xplan.display_awr(sql_id,plan_hash_value,db_id,format));

-plan_hash_value:toselectaspecificplan

-dbid:specifieswhichdatabasetoselectfrom

Displays plans stored in AWR;

Examplescript:

SELECT * FROM TABLE(dbms_xplan.display_awr('&&sql_id', '&plan_hash_value',

NULL, 'ALL +peeked_binds'));


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34

dbms_xplan.display_awr

SQL_ID 4jtbgawt37mcd--------------------Plan hash value: 327243540---------------------------------------------------------------------------------------------------------------| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |

---------------------------------------------------------------------------------------------------------------Peeked Binds (identified by position):--------------------------------------1 - :B3 (NUMBER): 73942 - :B2 (VARCHAR2(30), CSID=871): 'AAL'3 - :B1 (VARCHAR2(30), CSID=871): '73057'

SQL_ID 4jtbgawt37mcd--------------------Plan hash value: 2294473928---------------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |---------------------------------------------------------------------------------------------------------------

Peeked Binds (identified by position):--------------------------------------1 - :B3 (NUMBER): 96492 - :B2 (VARCHAR2(30), CSID=871): 'ZXU'3 - :B1 (VARCHAR2(30), CSID=871): 'U5152'

select * from table(dbms_xplan.display_awr('4jtbgawt37mcd',null,null, 'ALL +peeked_binds'));


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OraInternals Riyaj Shamsudeen 35

Cardinality feedback

Demo @demo_oh1.sql

select /*+ gather_plan_statistics */ max(length(v1)) fromorder_headers_all where processed_flag='N'


---------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows |

---------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | | 1 || 1 | SORT AGGREGATE | | 1 | 1 | 1 ||* 2 | TABLE ACCESS FULL| ORDER_HEADERS_ALL | 1 | 50000 | 10 |---------------------------------------------------------------------------


---------------------------------------------------

2 - filter("PROCESSED_FLAG"='N')


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Starts

Demo @demo_oh2.sql

SELECT/*+ no_rewrite gather_plan_statistics */MAX(LENGTH(oh.v1)), MAX(LENGTH(oh.v1))

FROM order_headers_all ohWHERE EXISTS

( SELECT 1 FROM order_lines_all olWHERE oh.order_id = ol.order_idAND line_processed_flag = 'Y'AND rownum >=1)

AND oh.processed_flag='N' ;

How many times did the EXISTS

Subquery was executed?


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ALLSTATS LAST

Demo @demo_oh2.sql

----------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows |----------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | | 1 || 1 | SORT AGGREGATE | | 1 | 1 | 1 ||* 2 | FILTER | | 1 | | 10 ||* 3 | TABLE ACCESS FULL | ORDER_HEADERS_ALL | 1 | 50000 | 10 || 4 | COUNT | | 10 | | 10 ||* 5 | FILTER | | 10 | | 10 ||* 6 | TABLE ACCESS BY INDEX ROWID| ORDER_LINES_ALL | 10 | 1 | 10 ||* 7 | INDEX RANGE SCAN | OL_N1 | 10 | 1 | 10 |----------------------------------------------------------------------------------------


2 - filter( IS NOT NULL)

3 - filter("OH"."PROCESSED_FLAG"='N')5 - filter(ROWNUM>=1)6 - filter("LINE_PROCESSED_FLAG"='Y')7 - access("OL"."ORDER_ID"=:B1)

select * from table (dbms_xplan.display_cursor ('', '','ALLSTATS LAST'))


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Starts ..2

SELECT 1 FROM PA_TASKS WHERE TASK_ID = :B1


--------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows |--------------------------------------------------------------------| 0 | SELECT STATEMENT | | 256K| | 246K||* 1 | INDEX UNIQUE SCAN| PA_TASKS_U1 | 256K| 1 | 246K|--------------------------------------------------------------------


1 - access("TASK_ID"=:B1)

select * from table (dbms_xplan.display_cursor ('', '','ALLSTATS'))

How many times did we

execute this statement?


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Cardinality feedback ..2

------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows |------------------------------------------------------------------------------------------| 0 | UPDATE STATEMENT | | 7822 | | 0 || 1 | UPDATE | ENI_OLTP_ITEM_STAR | 7822 | | 0 ||* 2 | FILTER | | 7824 | | 7254K||* 3 | TABLE ACCESS BY ROWID RANGE| ENI_OLTP_ITEM_STAR | 7823 | 69121 | 7256K|| 4 | TABLE ACCESS BY INDEX ROWID | MTL_SYSTEM_ITEMS_B | 7171K| 1 | 7167K||* 5 | INDEX UNIQUE SCAN | MTL_SYSTEM_ITEMS_B_U1 | 7176K| 1 | 7172K|------------------------------------------------------------------------------------------

select * from table (dbms_xplan.display_cursor ('', '','ALLSTATS'))


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Cardinality feedback ..3

-------------------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | A-Time | Buffers | Reads |-------------------------------------------------------------------------------------------------------| 0 | UPDATE STATEMENT | | 7822 |00:47:24.86 | 56M| 1082K|| 1 | UPDATE | ENI_OLTP_ITEM_STAR | 7822 |00:47:24.86 | 56M| 1082K||* 2 | FILTER | | 7824 |00:01:27.46 | 23M| 868 ||* 3 | TABLE ACCESS BY ROWID RANGE| ENI_OLTP_ITEM_STAR | 7823 |00:01:23.30 | 23M| 868 || 4 | TABLE ACCESS BY INDEX ROWID | MTL_SYSTEM_ITEMS_B | 7171K|00:41:09.13 | 25M| 1028K||* 5 | INDEX UNIQUE SCAN | MTL_SYSTEM_ITEMS_B_U1 | 7176K|00:01:17.74 | 17M| 488 |-------------------------------------------------------------------------------------------------------Predicate Information (identified by operation id):---------------------------------------------------

2 - filter(CHARTOROWID(:B2)=CHARTOROWID(:B2) AND ROWID


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SQL - remote

Demo @demo_oh3.sql

WITH rem1 AS(SELECT /*+ materialize */ order_idFROM oli_table@orcl2 olWHERE line_processed_flag='Y'

)SELECT /*+ no_rewrite gather_plan_statistics */MAX(LENGTH(oh.v1)) FROM order_headers_all oh

WHERE EXISTS(SELECT 1 FROM rem1 WHERE oh.order_id = rem1.order_id)

AND oh.processed_flag='N' ;


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Remote queries

Demo @demo_oh3.sql

---------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows |

---------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | | 1 || 1 | TEMP TABLE TRANSFORMATION | | 1 | | 1 || 2 | LOAD AS SELECT | | 1 | | 0 || 3 | REMOTE | OLI_TABLE | 1 | 100K| 100K|| 4 | SORT AGGREGATE | | 1 | 1 | 1 ||* 5 | HASH JOIN RIGHT SEMI | | 1 | 50000 | 10 || 6 | VIEW | | 1 | 100K| 100K|| 7 | TABLE ACCESS FULL | SYS_TEMP_0FD9FC884_E8A367F2 | 1 | 100K| 100K||* 8 | TABLE ACCESS FULL | ORDER_HEADERS_ALL | 1 | 50000 | 10 |---------------------------------------------------------------------------------------------


5 - access("OH"."ORDER_ID"="REM1"."ORDER_ID")8 - filter("OH"."PROCESSED_FLAG"='N')

Remote SQL Information (identified by operation id):----------------------------------------------------

3 - SELECT /*+ */ "ORDER_ID","LINE_PROCESSED_FLAG"FROM "OLI_TABLE" "OL" WHERELINE_PROCESSED_FLAG"='Y' (accessing

ORCL2.ORACLE.com' )

ADVANCED option providesremote query output


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SQL remote ..2

Demo @demo_oh3.sql

SELECT/*+ no_rewrite gather_plan_statistics use_nl (oh ol) */MAX(LENGTH(oh.v1))

FROM order_headers_all oh,

(SELECT order_idFROM oli_table@orcl2 olWHERE line_processed_flag='Y') ol

WHERE oh.order_id = ol.order_id ANDoh.processed_flag='N' ;


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Remote queries (2)

Demo @demo_oh5.sql

------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|IN-OUT|-------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | | | 100K(100)| || 1 | SORT AGGREGATE | | 1 | 223 | | || 2 | NESTED LOOPS | | 50000 | 10M| 100K (1)| ||* 3 | TABLE ACCESS FULL| ORDER_HEADERS_ALL | 50000 | 9M| 403 (7)| || 4 | REMOTE | OLI_TABLE | 1 | 15 | 2 (0)| R->S |-------------------------------------------------------------------------------------


3 - filter("OH"."PROCESSED_FLAG"='N')

Remote SQL Information (identified by operation id):----------------------------------------------------

4 - SELECT /*+ USE_NL ("OL") */ "ORDER_ID","LINE_PROCESSED_FLAG" FROM "OLI_TABLE" "OL" WHERE

"LINE_PROCESSED_FLAG"='Y' AND :1="ORDER_ID(accessing ORCL2.ORCL.COM' )


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Parallel Queries

----------------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time |----------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | | 1 |00:00:08.83 || 1 | SORT AGGREGATE | | 1 | 1 | 1 |00:00:08.83 ||* 2 | HASH JOIN | | 1 | 999K| 260K|00:00:08.76 || 3 | VIEW | | 1 | 999K| 999K|00:00:02.11 ||* 4 | COUNT STOPKEY | | 1 | | 999K|00:00:01.52 || 5 | PX COORDINATOR | | 1 | | 999K|00:00:00.84 || 6 | PX SEND QC (RANDOM) | :TQ10000 | 0 | 11M| 0 |00:00:00.01 ||* 7 | COUNT STOPKEY | | 0 | | 0 |00:00:00.01 || 8 | PX PARTITION HASH ALL| | 0 | 11M| 0 |00:00:00.01 || 9 | INDEX FULL SCAN | OE_ORDER_HEADERS_U1 | 0 | 11M| 0 |00:00:00.01 || 10 | VIEW | | 1 | 999K| 999K|00:00:02.28 ||* 11 | COUNT STOPKEY | | 1 | | 999K|00:00:01.68 || 12 | INDEX FULL SCAN | OE_ORDER_LINES_N1 | 1 | 57M| 999K|00:00:00.98 |----------------------------------------------------------------------------------------------------


2 - access("OH"."HEADER_ID"="OL"."HEADER_ID")4 - filter(ROWNUM


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Parallel Queries

---------------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time |----------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | | 1 |00:00:08.83 || 1 | SORT AGGREGATE | | 1 | 1 | 1 |00:00:08.83 ||* 2 | HASH JOIN | | 1 | 999K| 260K|00:00:08.76 || 3 | VIEW | | 1 | 999K| 999K|00:00:02.11 ||* 4 | COUNT STOPKEY | | 1 | | 999K|00:00:01.52 || 5 | PX COORDINATOR | | 1 | | 999K|00:00:00.84 || 6 | PX SEND QC (RANDOM) | :TQ10000 | 0 | 11M| 0 |00:00:00.01 ||* 7 | COUNT STOPKEY | | 8 | | 1072K|00:00:03.83 || 8 | PX PARTITION HASH ALL| | 8 | 11M| 1072K|00:00:03.17 || 9 | INDEX FULL SCAN | OE_ORDER_HEADERS_U1 | 8 | 11M| 1072K|00:00:02.56 || 10 | VIEW | | 1 | 999K| 999K|00:00:02.28 ||* 11 | COUNT STOPKEY | | 1 | | 999K|00:00:01.68 || 12 | INDEX FULL SCAN | OE_ORDER_LINES_N1 | 1 | 57M| 999K|00:00:00.98 |----------------------------------------------------------------------------------------------------


2 - access("OH"."HEADER_ID"="OL"."HEADER_ID")4 - filter(ROWNUM


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Parallel Queries

----------------------------------------------------------------------------------------------------| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time |----------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 4 | | 4 |00:00:38.25 || 1 | SORT AGGREGATE | | 4 | 1 | 4 |00:00:38.25 ||* 2 | HASH JOIN | | 4 | 999K| 418K|00:00:38.16 || 3 | VIEW | | 4 | 999K| 3999K|00:00:07.67 ||* 4 | COUNT STOPKEY | | 4 | | 3999K|00:00:05.53 || 5 | PX COORDINATOR | | 4 | | 3999K|00:00:03.12 || 6 | PX SEND QC (RANDOM) | :TQ10000 | 0 | 11M| 0 |00:00:00.01 |

|* 7 | COUNT STOPKEY | | 64 | | 4779K|00:00:56.27 || 8 | PX PARTITION HASH ALL| | 64 | 11M| 4779K|00:00:53.19 || 9 | INDEX FULL SCAN | OE_ORDER_HEADERS_U1 | 64 | 11M| 4779K|00:00:50.33 || 10 | VIEW | | 4 | 999K| 3999K|00:00:14.59 ||* 11 | COUNT STOPKEY | | 4 | | 3999K|00:00:12.32 || 12 | PX COORDINATOR | | 4 | | 3999K|00:00:09.35 || 13 | PX SEND QC (RANDOM) | :TQ20000 | 0 | 57M| 0 |00:00:00.01 ||* 14 | COUNT STOPKEY | | 64 | | 4169K|00:05:45.40 || 15 | PX BLOCK ITERATOR | | 64 | 57M| 4169K|00:05:42.68 ||* 16 | TABLE ACCESS FULL | OE_ORDER_LINES_ALL | 233 | 57M| 4169K|00:05:26.98 |----------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):---------------------------------------------------..

Note-----

- Degree of Parallelism is 16 because of hint

ALLSTATSAfter 4 executions with DOP=16


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Note section

Note-----

- dynamic sampling used for this statement (level=2)

Note-----

- SQL profile SQL_PROF_4awcsbtwr8ksz" used for thisstatement

Note-----

- Cardinality feedback used


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Few limitations

Display_awr does not store predicates.

Of course , not all SQL statements are stored in AWR

repository (color important statements).

Display_cursor is not RAC aware. You can query the plans

only from the local instances using display_cursor.

Run time statistics are printed only after the completion ofSQL statements (Think production long running queries).


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SQL monitor

SET LONG 1000000SET LONGCHUNKSIZE 1000000SET LINESIZE 1000SET PAGESIZE 0SET TRIM ON

SET TRIMSPOOL ONSET ECHO OFFSET FEEDBACK OFF

SELECT DBMS_SQLTUNE.report_sql_monitor(sql_id => '&sql_id', type=>'TEXT' , report_level => 'ALL') from dual

/


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Output


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Output ..2


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Thank you for attending!

If you like this presentation, you will love my2-part intensive, online RAC webinar.

http://www.orainternals.com/training/

advanced-rac-training

Email: [email protected]

Week Dates Time

Week1 TBA 8AM 2PM PDT

Week 2 TBA 8AM - 2PM PDT


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References

Oracle support site. Metalink.oracle.com. Various documents

Troubleshooting Oracle performance - Christian Antongini

http://www.orainternals.com/papers - Riyaj Shamsudeen Various article from web led through on google search

Tom Kytes website Asktom.oracle.com

Documents

AWR dbms_xplan