1

Tuning with Oracle’s SQL TraceDavid KurtzGo-Faster Consultancy Ltd.

david@go-faster.co.uk

www.go-faster.co.uk

2

Message from the SIG management

• Keep filling in the critique forms

• Keep suggesting topics– This is session was a requested topic

• Offer to talk on topic about which you know

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Who am I?

• DBA– Independent consultant– Performance tuning

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Tuning with Oracle’s SQL Trace

• Overview of Tuning

• Explain Plan

• Enabling SQL Trace

• TKPROF

• Interpreting Execution Plans

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Rules of Engagement

• Interrupt me:– if you think I have got something wrong– if you have a question– if you can’t hear me

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What is Tuning?

• It is a much abused term

• What does a person mean when they say ‘Tuning’

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Oracle Designing and Tuning for Performance Manual

• New name in Oracle 8i

• Used to be the ‘Tuning’ manual

• A good place to start

• Always there

• Free

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Oracle Designing and Tuning for Performance Manual

• Chapters4. The Optimiser

5. Using Explain Plan

6. Using SQL Trace and TKPROF

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When should I start to Tune?

• NOW is already too late

from ‘Oracle Designing and Tuning for Performance’

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Tuning occurs at Different Levels

• business design

• data design

• application design

• logical structure of the database

• database operations

• access paths

• memory allocation

• I/O and physical structure

• resource contention

• platform

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Tuning is a search for lost time

• Identify problem SQL

• Find out why it is a problem– SQL execution plan

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Explain plan

• Explain plan for <sql statement>– PLAN_TABLE

• set autotrace on

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Rule -v- Cost Based Optimiser

select /*+RULE*/ * from dual;

Execution Plan--------------------------

-0 SELECT STATEMENT

Optimizer=HINT: RULE

1 0 TABLE ACCESS (FULL) OF 'DUAL'

select /*+ALL_ROWS*/ * from dual;

Execution Plan---------------------------0 SELECT STATEMENT

Optimizer=HINT: ALL_ROWS (Cost=1 Card=1 Bytes=2)

1 0 TABLE ACCESS (FULL) OF 'DUAL'

(Cost=1 Card=1 Bytes=2)

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SQL Trace

• Whole database– SQL_TRACE=TRUE

• Current Session– ALTER SESSION SET SQL_TRACE=TRUE;– sys.dbms_session.set_sql_trace(true)

• A different session– sys.dbms_system.set_sql_trace_in_session

(<sid>,<serial#>,TRUE);

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USER_DUMP_DEST

• Trace file written to directory– USER_DUMP_DEST

• Default– $ORACLE_HOME/rdbms/log/

• System level– ALTER SYSTEM SET

USER_DUMP_DEST=newdir

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MAX_DUMP_FILE_SIZE

• Maximum size of trace file– Kbytes / OS blocks– Shadow process will stop writing when

maximum reached– grep "DUMP FILE SIZE IS LIMITED”

• Beware– Truncated trace file– Full File System

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Timed Statistics

• Enable to get statement and other timings

• Initialisation file– TIMED_STATISTICS=TRUE

• Ad-hoc– ALTER SYSTEM SET

TIMED_STATISTICS=TRUE;

• Small performance overhead

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Trace File (Unix)

• Difficult to read, but useful informationDump file

/PS/oracle/app/oracle/product/8.0.5/rdbms/log/psperf_ora_20437.trcOracle8 Enterprise Edition Release 8.0.5.0.0 - ProductionPL/SQL Release 8.0.5.0.0 - ProductionORACLE_HOME = /PS/oracle/app/oracle/product/8.0.5System name:SunOSNode name: hqmain01Release: 5.6Version: Generic_105181-08Machine: sun4uInstance name: PSPERFRedo thread mounted by this instance: 1Oracle process number: 30Unix process pid: 20437, image: oraclePSPERF

*** SESSION ID:(30.3900) 1999.02.25.16.15.06.000

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Trace File (NT)

Dump file c:\user\ppt\tuning with Oracle Trace\demo\ORA00298.TRCTue May 16 20:02:47 2000ORACLE V8.1.6.0.0 - Production vsnsta=0vsnsql=e vsnxtr=3Windows NT Version 4.0 Service Pack 6, CPU type 586Oracle8i Enterprise Edition Release 8.1.6.0.0 - ProductionWith the Partitioning optionJServer Release 8.1.6.0.0 - ProductionWindows NT Version 4.0 Service Pack 6, CPU type 586Instance name: f75do81

Redo thread mounted by this instance: 1

Oracle process number: 9

Windows thread id: 298, image: ORACLE.EXE

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Trace file

• Lists every statement PARSING IN CURSOR #1 len=33 dep=0 uid=21 oct=42 lid=21

tim=1118983 hv=3176041220 ad='809c49a4' ALTER SESSION SET SQL_TRACE=TRUEEND OF STMTEXEC #1:c=0,e=2,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=4,tim=1118983

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Trace file

• Contains the execution planEND OF STMTPARSE #1:c=44,e=45,p=42,cr=1821,cu=4,mis=1,r=0,dep=0,og=4,tim=1120108*** 1999.02.25.16.17.58.000EXEC #1:c=15661,e=16023,p=164769,cr=3981545,cu=0,mis=0,r=0,dep=0,og=4,tim=1136131EXEC #2:c=0,e=3,p=4,cr=1,cu=3,mis=0,r=1,dep=0,og=4,tim=1136134STAT #1 id=1 cnt=0 pid=0 pos=0 obj=0 op='SORT UNIQUE 'STAT #1 id=2 cnt=0 pid=1 pos=1 obj=0 op='FILTER 'STAT #1 id=3 cnt=0 pid=2 pos=1 obj=0 op='NESTED LOOPS 'STAT #1 id=4 cnt=8 pid=3 pos=1 obj=0 op='NESTED LOOPS 'STAT #1 id=5 cnt=1000040 pid=4 pos=1 obj=0 op='NESTED LOOPS 'STAT #1 id=6 cnt=360 pid=5 pos=1 obj=0 op='NESTED LOOPS 'STAT #1 id=7 cnt=10 pid=6 pos=1 obj=0 op='NESTED LOOPS 'STAT #1 id=8 cnt=10 pid=7 pos=1 obj=10009 op='TABLE ACCESS BY INDEX ROWID

PS_PP_PAYMENT_TMP ’...

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TKPROF

• Processes the trace file– removes recursive SQL– generate execution plans– aggregate duplicates– sort by criteria– top n statements

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Plan Table

• $ORACLE_HOME/rdbms/admin/

utlxplan.sql– builds plan table

• either make it local to a user,

• or create a public synonym and issue grants

• $ORACLE_HOME/rdbms/admin/

utltkprf.sql

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TKPROF Command

Usage: tkprof tracefile outputfile [explain= ] [table= ] [print= ] [insert= ] [sys= ] [sort= ] table=schema.tablename Use 'schema.tablename' with 'explain=' option. explain=user/password Connect to ORACLE and issue EXPLAIN PLAIN. print=integer List only the first 'integer' SQL statements. aggregate=yes|no insert=filename List SQL statements and data inside INSERT statements. sys=no TKPROF does not list SQL statements run as user SYS. record=filename Record non-recursive statements found in the trace file. sort=option Set of zero or more of the following sort options:... execnt number of execute was called execpu cpu time spent executing exeela elapsed time executing exedsk number of disk reads during execute exeqry number of buffers for consistent read during execute execu number of buffers for current read during execute exerow number of rows processed during execute exemis number of library cache misses during execute...

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SQL statement

INSERT INTO PS_PP_CUST_TMP2 ( PROCESS_INSTANCE, DEPOSIT_BU, DEPOSIT_ID, PAYMENT_SEQ_NUM, CUST_ID, PAYMENT_AMT, PAYMENT_DT, PP_METHOD, SETID, SUBCUST_QUAL1, SUBCUST_QUAL2, PP_HOLD, PP_MET_SW, PAYMENT_CURRENCY ) SELECT DISTINCT P.PROCESS_INSTANCE, P.DEPOSIT_BU, P.DEPOSIT_ID, P.PAYMENT_SEQ_NUM, C.CUST_ID, P.PAYMENT_AMT, P.PAYMENT_DT, O.PP_METHOD, O.SETID, C.SUBCUST_QUAL1, C.SUBCUST_QUAL2, O.PP_HOLD, 'N', P.PAYMENT_CURRENCY FROM PS_CUST_OPTION O, PS_ITEM I, PS_CUSTOMER C, PS_SET_CNTRL_REC S, PS_PAYMENT_ID_ITEM X, PS_PP_PAYMENT_TMP P WHERE P.PROCESS_INSTANCE = 212 AND S.RECNAME = 'CUSTOMER' AND S.SETID = C.SETID AND S.SETCNTRLVALUE = I.BUSINESS_UNIT AND I.CUST_ID = C.CUST_ID AND I.ITEM_STATUS = 'O' AND O.SETID = C.REMIT_FROM_SETID AND O.CUST_ID = C.REMIT_FROM_CUST_ID AND O.EFFDT = ( SELECT MAX(Z.EFFDT) FROM PS_CUST_OPTION Z WHERE Z.SETID = O.SETID AND Z.CUST_ID = O.CUST_ID AND Z.EFF_STATUS = 'A' AND Z.EFFDT <= P.PAYMENT_DT ) AND O.PP_METHOD <> ' ' AND P.DEPOSIT_BU = X.DEPOSIT_BU AND P.DEPOSIT_ID = X.DEPOSIT_ID AND P.PAYMENT_SEQ_NUM = X.PAYMENT_SEQ_NUM AND X.REF_QUALIFIER_CODE = 'I' AND X.REF_VALUE = I.ITEM

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Statistics

…count = number of times OCI procedure was executedcpu = cpu time in seconds executing elapsed = elapsed time in seconds executingdisk = number of physical reads of buffers from diskquery = number of buffers gotten for consistent readcurrent = number of buffers gotten in current mode (usually for

update)rows = number of rows processed by the fetch or execute call…call count cpu elapsed disk query current rows------- ------ -------- ---------- ---------- ---------- ---------- ----------Parse 1 0.31 0.33 4 0 4 0Execute 1 156.61 160.23 164769 3981545 0 0Fetch 0 0.00 0.00 0 0 0 0------- ------ -------- ---------- ---------- ---------- ---------- ----------total 2 156.92 160.56 164773 3981545 4 0

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Execution plan (Oracle 8.1 only)

Rows Execution Plan------- --------------------------------------------------- 0 INSERT STATEMENT GOAL: CHOOSE 0 SORT (UNIQUE) 0 FILTER 0 NESTED LOOPS 8 NESTED LOOPS1000040 NESTED LOOPS 360 NESTED LOOPS 10 NESTED LOOPS 10 TABLE ACCESS BY INDEX ROWID PS_PP_PAYMENT_TMP 11 INDEX (RANGE SCAN) (object id 9329) 20 INDEX (RANGE SCAN) OF (object id 8105) 360 TABLE ACCESS (BY INDEX ROWID) OF 'PS_SET_CNTRL_REC' 370 INDEX (RANGE SCAN) OF (object id 12020)1000040 TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUSTOMER'1000400 INDEX (RANGE SCAN) OF (object id 4751)1000048 INDEX (RANGE SCAN) OF 'PS#ITEM' (NON-UNIQUE) 8 TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUST_OPTION' 16 INDEX (RANGE SCAN) OF (object id 4854) 0 SORT (AGGREGATE) 0 TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUST_OPTION' 0 INDEX (RANGE SCAN) OF (object id 4854)

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Execution plan (if you connect TKPROF to the database)

Rows Execution Plan------- --------------------------------------------------- 0 INSERT STATEMENT GOAL: CHOOSE 0 SORT (UNIQUE) 0 FILTER 0 NESTED LOOPS 8 NESTED LOOPS1000040 NESTED LOOPS 360 NESTED LOOPS 10 NESTED LOOPS 10 TABLE ACCESS (BY INDEX ROWID) OF 'PS_PP_PAYMENT_TMP' 11 INDEX (RANGE SCAN) OF 'PSAPP_PAYMENT_TMP' (NON-UNIQUE) 20 INDEX (RANGE SCAN) OF 'PSAPAYMENT_ID_ITEM' (NON-UNIQUE) 360 TABLE ACCESS (BY INDEX ROWID) OF 'PS_SET_CNTRL_REC' 370 INDEX (RANGE SCAN) OF 'PSBSET_CNTRL_REC' (NON-UNIQUE)1000040 TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUSTOMER'1000400 INDEX (RANGE SCAN) OF 'PS#CUSTOMER' (NON-UNIQUE)1000048 INDEX (RANGE SCAN) OF 'PS#ITEM' (NON-UNIQUE) 8 TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUST_OPTION' 16 INDEX (RANGE SCAN) OF 'PS_CUST_OPTION' (UNIQUE) 0 SORT (AGGREGATE) 0 TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUST_OPTION' 0 INDEX (RANGE SCAN) OF 'PS_CUST_OPTION' (UNIQUE)

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1. Make the statement readable

SELECT DISTINCT P.PROCESS_INSTANCE, P.DEPOSIT_BU, P.DEPOSIT_ID, P.PAYMENT_SEQ_NUM, C.CUST_ID, P.PAYMENT_AMT, P.PAYMENT_DT, O.PP_METHOD, O.SETID, C.SUBCUST_QUAL1, C.SUBCUST_QUAL2, O.PP_HOLD, 'N', P.PAYMENT_CURRENCY FROMPS_CUST_OPTION O, PS_ITEM I, PS_CUSTOMER C, PS_SET_CNTRL_REC S, PS_PAYMENT_ID_ITEM X, PS_PP_PAYMENT_TMP P WHERE P.PROCESS_INSTANCE = 212 AND S.RECNAME = 'CUSTOMER' AND S.SETID = C.SETID AND S.SETCNTRLVALUE = I.BUSINESS_UNIT AND I.CUST_ID = C.CUST_ID AND I.ITEM_STATUS = 'O' AND O.SETID = C.REMIT_FROM_SETID AND O.CUST_ID = C.REMIT_FROM_CUST_ID AND O.EFFDT = ( SELECT MAX(Z.EFFDT)

FROM PS_CUST_OPTION Z WHERE Z.SETID = O.SETID AND Z.CUST_ID = O.CUST_ID AND Z.EFF_STATUS = 'A' AND Z.EFFDT <= P.PAYMENT_DT)

AND O.PP_METHOD <> ' ' AND P.DEPOSIT_BU = X.DEPOSIT_BU AND P.DEPOSIT_ID = X.DEPOSIT_ID AND P.PAYMENT_SEQ_NUM = X.PAYMENT_SEQ_NUM AND X.REF_QUALIFIER_CODE = 'I' AND X.REF_VALUE = I.ITEM

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2. Start to draw the query

PS_C U STO M ERC

PS_C U ST_O PTIO NO

PS_ITEMI

PS_SET_C N TR L_R ECS

PS_PAYM EN T_ID _ITEMX

PS_PP_PAYM EN T_TM PP

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3. Put the joins in

PS _C U ST O M ERC

PS _C U ST _O PT IO NO

PS _IT E MI

PS _SE T_C N T R L_R E CS

PS _PA YM E N T _ID _IT EMX

PS _PP _PAY M E N T _TM PP

PRO CESS_INSTANCE= 212

RECNAM E = 'CUSTO M ER '

CU

ST

_ID

ITEM _STATUS = 'O '

O .SETID = C .REM IT_FRO M _SETIDO .CUST_ID = C .REM IT_FRO M _CUST_ID

EFFDT PP_M ETHO D <> ' '

DEPO SIT_BUDEPO SIT_ID

PAYM ENT_SEQ _NUM

REF_Q UALIF IER_CO DE = 'I'

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4. Get the order from the plan

0 FILTER 0 NESTED LOOPS 8 NESTED LOOPS1000040 NESTED LOOPS 360 NESTED LOOPS 10 NESTED LOOPS 10 (1)TABLE ACCESS (BY INDEX ROWID) OF 'PS_PP_PAYMENT_TMP' 11 INDEX (RANGE SCAN) OF 'PSAPP_PAYMENT_TMP' (NON-UNIQUE) 20 (2)INDEX (RANGE SCAN) OF 'PSAPAYMENT_ID_ITEM' (NON-UNIQUE) 360 (3)TABLE ACCESS (BY INDEX ROWID) OF 'PS_SET_CNTRL_REC' 370 INDEX (RANGE SCAN) OF 'PSBSET_CNTRL_REC' (NON-UNIQUE)1000040 (4)TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUSTOMER'1000400 INDEX (RANGE SCAN) OF 'PS#CUSTOMER' (NON-UNIQUE)1000048 (5)INDEX (RANGE SCAN) OF 'PS#ITEM' (NON-UNIQUE) 8 (6)TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUST_OPTION' 16 INDEX (RANGE SCAN) OF 'PS_CUST_OPTION' (UNIQUE) 0 SORT (AGGREGATE) 0 TABLE ACCESS (BY INDEX ROWID) OF 'PS_CUST_OPTION' INDEX (RANGE SCAN) OF 'PS_CUST_OPTION' (UNIQUE)

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5. Put the order in the diagram

PS_PP_PAYM EN T_TM PP (1)

PS_C U STO M ERC (4)

PS_C U ST_O PTIO NO (6)

PS_ITEMI (5)

PS_SET_C N TR L_R ECS (3)

PS_PAYM EN T_ID _ITEMX (2)

PRO CESS_INSTANCE= 212

RECNAM E = 'CUSTO MER'

CU

ST

_ID

ITEM_STATUS = 'O '

O .SETID = C .REM IT_FRO M _SETIDO .CUST_ID = C .REM IT_FRO M _CUST_ID

EFFDT PP_M ETHO D <> ' '

DEPO SIT_BUDEPO SIT_ID

PAYMENT_SEQ _NUM

REF_Q UALIF IER_CO DE = 'I'

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6. This time, the answer is an index

CREATE INDEX PSBITEM ON PS_ITEM (ITEM, CUST_ID, BUSINESS_UNIT, ITEM_STATUS) TABLESPACE PSINDEX STORAGE (INITIAL 10K NEXT 98K MAXEXTENTS 110 PCTINCREASE 0)

/

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New execution order

PS_PP_PAYM EN T_TM PP (1)

PS_C U STO M ERC (5)

PS_C U ST_O PTIO NO (6)

PS_ITEMI (3)

PS_SET_C N TR L_R ECS (4)

PS_PAYM EN T_ID _ITEMX (2)

PRO CESS_INSTAN C E= 212

R EC N AM E = 'C USTO M ER '

CU

ST

_ID

ITEM _STATU S = 'O '

O .SET ID = C .R EM IT_FR O M _SETIDO .CU ST_ID = C .R EM IT_FR O M _C UST_ID

EFFDT PP_M ETH O D <> ' '

D EPO SIT_BUD EPO SIT_ID

PAYM EN T_SEQ _N U M

R EF_Q UALIF IER_C O DE = 'I'

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Statistics

Before

call count cpu elapsed disk query current rows------- ------ -------- ---------- ---------- ---------- ---------- ----------Parse 1 0.31 0.33 4 0 4 0Execute 1 156.61 160.23 164769 3981545 0 0Fetch 0 0.00 0.00 0 0 0 0------- ------ -------- ---------- ---------- ---------- ---------- ----------total 2 156.92 160.56 164773 3981545 4 0

After

call count cpu elapsed disk query current rows------- ------ -------- ---------- ---------- ---------- ---------- ----------Parse 1 0.35 2.56 3 0 3 0Execute 1 0.03 0.05 38 289 3 0Fetch 0 0.00 0.00 0 0 0 0------- ------ -------- ---------- ---------- ---------- ---------- ----------total 2 0.38 2.61 41 289 6 0

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Theory & Practice

• Tuning• Explain Plan• SQL Trace• TKPROF• Graphical Technique

• How and what to trace a real system?

• Do you have access to the source code?

• Can you alter the code?

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How to SQL_Trace PeopleSoft?

• Client

• Query/Crystal & Database Agent

• SQR

• Cobol

• AE

• nVision

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Client

• Multithreaded

• 2-tier, 3-tier– Client trace - SQLcleanup.exe

• SQL Script

• Work in SQL*Plus

– Small application server• no PSQCKSRV or PSQRYSRV

• enable trace on PSAPPSRV

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PS/Query, Crystal, Database Agent

• Trace Application Server– PSQRYSRV

• Cut and paste SQL PS/Query– work in SQL*Plus

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nVision

• Trace PSQRYSRV

• Client trace & SQLcleanup.exe

• Cut and paste the statement directly

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Mass Change

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Application Engine

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SQR

• session.sqc

begin-sqlALTER SESSION SET SQL_TRACE=TRUEend-SQL

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Cobol

• Difficult to add extra statements

• Batch

• Initiated via Process Scheduler– Data driven agent– Table of requests– Each request has a status

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Cobol

• Trigger on process request table

create or replace trigger sysadm.set_tracebefore update of runstatus on sysadm.psprcsrqstfor each rowwhen (new.runstatus = 7 and old.runstatus != 7 and new.prcstype = 'COBOL SQL'and new.prcsname = 'GLPJEDIT' and new.oprid = 'VP1' and new.servernamerqst = 'PSUNX' and new.rqstdttm <= TO_DATE(‘16062000’,’DDMMYYYY’))begin sys.dbms_session.set_sql_trace(true);exception when others then null;end;/

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Trigger

• with log

create or replace trigger sysadm.set_trace

before update of runstatus on sysadm.psprcsrqst

for each row

when (new.runstatus = 7 and old.runstatus != 7 and not new.prcstype IN('Crystal','PSJob','Database Agent'))

begin

insert into dmk_trace_log

(prcsinstance, oracle_shadow, timestamp)

select :new.prcsinstance, p.spid, sysdate

from v$session s, v$process p

where s.sid = (select sid from v$mystat where rownum = 1)

and s.paddr = p.addr;

sys.dbms_session.set_sql_trace(true);

exception when others then null;end;

/

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Autonomous Trigger

• New in Oracle 8.1create or replace trigger sysadm.set_tracebefore update of runstatus on sysadm.psprcsrqst for each rowwhen (new.runstatus = 7 and old.runstatus != 7 and not new.prcstype

IN('Crystal','PSJob','Database Agent'))declare pragma autonomous_transaction;begin insert into dmk_trace_log (prcsinstance, oracle_shadow, timestamp) select :new.prcsinstance, p.spid, sysdate from v$session s, v$process p where s.sid = (select sid from v$mystat where rownum = 1) and s.paddr = p.addr; sys.dbms_session.set_sql_trace(true); commit; --only allowed & mandatory in autonomous trigger

exception when others then null;end;/

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Tuning with Oracle’s SQL Trace

• Tuning

• SQL Trace

• TKPROF

• Explain Plan

• Graphical Technique

• Techniques for enabling SQL Trace

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Any Questions?

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Tuning with Oracle’s SQL TraceDavid KurtzGo-Faster Consultancy Ltd.

david@go-faster.co.uk

www.go-faster.co.uk