Performance tuning in PL/SQL code

Hi,
I am working on already existing PL/SQL code which is written by someone else on validation and conversion of data from a temporary table to base table. It usually has 3.5 million rows. and the procedure takes arount 2.5 - 3 hrs to complete.
Can I enhance the PL/SQL code for better performance ? or, is this OK to take so long to process these many rows?
Thanks!
Yogini

Can I enhance the PL/SQL code for better performance ? Probably you can enhance it.
or, is this OK to take so long to process these many rows? It should take a few minutes, not several hours.
But please provide some more details like your database version etc.
I suggest to TRACE the session that executes the PL/SQL code, with WAIT events, so you'll see where and on what time is spent, you'll identify your 'problem statements very quickly' (after you or your DBA have TKPROF'ed the trace file).
SQL> alter session set events '10046 trace name context forever, level 12';
SQL> execute your PL/SQL code here
SQL> exitWill give you a .trc file in your udump directory on the server.
http://www.oracle-base.com/articles/10g/SQLTrace10046TrcsessAndTkprof10g.php
Also this informative thread can give you more ideas:
HOW TO: Post a SQL statement tuning request - template posting
as well as doing a search on 10046 at AskTom, http://asktom.oracle.com will give you more examples.
and reading Oracle's Performance Tuning Guide: http://www.oracle.com/pls/db102/to_toc?pathname=server.102%2Fb14211%2Ftoc.htm&remark=portal+%28Getting+Started%29

Similar Messages

Performance issue with pl/sql code

Hi Oracle Gurus,
I am in need of your recommendations for a performance issue that I am facing in production envrionment. There is a pl/sql procedure which executes with different elapsed time at different executions. Elapsed Times are 30minutes , 40 minutes, 65 minutes , 3 minutes ,3 seconds.
Expected elapsed time is maximum of 3 minutes. ( But some times it took 3 seconds too...! )
Output on all different executions are same that is deletion and insertion of 12K records into a table.
Here is the auto trace details of two different scenarios.
Slow execution - 33.65 minutes
Stat Name Statement Per Execution % Snap
Elapsed Time (ms) 1,712,343 1,712,342.6 41.4
CPU Time (ms) 1,679,689 1,679,688.6 44.7
Executions 1 N/A N/A
Buffer Gets ########## 167,257,973.0 86.9
Disk Reads 1,284 1,284.0 0.4
Parse Calls 1 1.0 0.0
User I/O Wait Time (ms) 4,264 N/A N/A
Cluster Wait Time (ms) 3,468 N/A N/A
Application Wait Time (ms) 0 N/A N/A
Concurrency Wait Time (ms) 6 N/A N/A
Invalidations 0 N/A N/A
Version Count 4 N/A N/A
Sharable Mem(KB) 85 N/A N/A
 -------------------------------------------------------------Fast Exection : 5 seconds
Stat Name Statement Per Execution % Snap
Elapsed Time (ms) 41,550 41,550.3 0.7
CPU Time (ms) 40,776 40,776.3 1.0
Executions 1 N/A N/A
Buffer Gets 2,995,677 2,995,677.0 4.2
Disk Reads 22 22.0 0.0
Parse Calls 1 1.0 0.0
User I/O Wait Time (ms) 162 N/A N/A
Cluster Wait Time (ms) 621 N/A N/A
Application Wait Time (ms) 0 N/A N/A
Concurrency Wait Time (ms) 55 N/A N/A
Invalidations 0 N/A N/A
Version Count 4 N/A N/A
Sharable Mem(KB) 85 N/A N/A
 -------------------------------------------------------------For security reasons, I cannot share the actual code. Its a report generating code that deletes and load the data into table using insert into select statement.
Delete from table ;
cursor X to get the master data ( 98 records )
For each X loop
insert into tableA select * from tables where a= X.a and b= X.b and c=X.c ..... ;
-- 12 K records inserted on average
insert into tableB select * from tables where a= X.a and b= X.b and c=X.c ..... ;
-- 12 K records inserted on average
end loop ;1. The select query is complex with bind variables ( explain plan varies for each values )
2. I have checked the tablespace of the tables involved, it is 82% used. DBA confirmed that it is not the reason.
3. Disk reads are high during long execution.
4. At long running times, I can see a db sequential read wait event on a index object. This index is on the table where data is inserted.
All I need to find is why this code is taking 3 seconds and 60 minutes on the same day and on the consecutive executions ?
Is there any other approach to find the root cause of this behaviour and to fix it ? Kindly adivse.
Thanks in advance your help.
Regards,
Hari
Edited by: BluShadow on 26-Sep-2012 08:24
edited to add {noformat}{noformat} tags. You've been a member long enough to know to do this yourself... so please do so in future. ({message:id=9360002})

Hariharan ST wrote:
Hi Oracle Gurus,
I am in need of your recommendations for a performance issue that I am facing in production envrionment. There is a pl/sql procedure which executes with different elapsed time at different executions. Please reedit your post and add some code tags around the trace information. This would improve readability greatly and will help us to help you
example
{code}
select * from dual;{code}
Based upon your description I can imagine two things.
a) The execution plan for the select query does change frequently.
A typical reason can be not up to date statistics.
b) Some locking / wait conflict. For example upon a UK index.
Are there any other operations going on while it is slow? If anybody inserts a value, then your session will wait, if the same (PK/UK) value also is to be inserted.
Those wait events can be recognized using standard tools like oracle sql developer or enterprise manager while the query is slow.
Also go through the links that are in the FAQ. They tell you how to get better information for makeing a tuning request.
SQL and PL/SQL FAQ
Edited by: Sven W. on Sep 25, 2012 6:41 PM

Improve performance on specific PL/SQL code

In these three querys there are identical "select" statements in the "where" sections of the querys.
SELECT sum(num_tit_par)
INTO posicion
FROM posi_hoy_rbo
WHERE fec_pos = fecha
and enti_cli in (select cod_int_ent from enti_rbo where enti_efe = entidad);
SELECT sum(mctasald)
INTO saldo_cuenta
FROM gbinmcta_rbo
WHERE mctafech = fecha
and mctaclav in (select cod_int_ent from enti_rbo where enti_efe = entidad);
SELECT sum(tarjdisp)
INTO saldo_tarjeta
FROM gbintarj_rbo
WHERE tarjfech = fecha
and tarjclav in (select cod_int_ent from enti_rbo where enti_efe = entidad);
Is there any way, using PL/SQL code, to store the results of this "select" statement in a kind of variable (varrays, nested tables...)
and then use this variable on the "where" clauses?. If it exists, could someone explain it in detail?
This way, I suppose that this "select" should be only once executed and the performance improved.
Thank You Very Much

Daniel,
I happened to have this code, which I posted in the past. simplified
You could ignore the creation of package and you could include the functionality of procedure A into procedure B in the following example,-- create a SQL type
SQL> create or replace type numTyp as table of number
2 /
Type created.
SQL> create or replace package test_pkg as
2    procedure B;
3 end;
4 /
Package created.
SQL> create or replace package body test_pkg as
2
2       numArray numTyp := numTyp(); -- initialize
3
3       procedure A Is -- Fills the array
4       Begin
5           numArray.extend(2);
6           numArray(1) := 10;
7           numArray(2) := 20;
8       End;
9
10       procedure B Is
11       Begin
12          A; -- call to procedure A
13          For rec in (select empno from my_emp where deptno IN
14                       (Select a.column_value val
15                          From THE ( select cast(numArray as numTyp) from dual ) a))
16          loop
17             dbms_output.put_line(rec.empno);
18          end loop;
19       end;
20 end;
21 /
Package body created.
SQL> exec test_pkg.B;
7782
7839
7934
7369
7876
7902
7788
7566
PL/SQL procedure successfully completed.Not a great example, but it shows how to use SQL type nested tables to use in SQL join operations. Hope it helps.
Thx,
Sri

Performance Tuning on PL/sql

Dear all,
I am not sure whether I am right to post this enquiry here, please correct me if I am wrong.
I have a sql stmt that run for a long time and caused a error of 'out of temp sapce' in oracle server. How can I tune my sql for better performance using command 'EXPLAIN PLAN'? How could I know the details information for those columns in the table 'PLAN_TABLE'?
Best Regards,
Marius

Read the "Database Performance Tuning Guide and Reference" for your version of Oracle (available online, right here).
Richard

Performance tuning of an SQL

Hi All,
I have a cursor which is giving performance issues. The query executed by the cursor is as below. There is no Full table scan on the first part of the UNION. But on the second part, there is a Full table scan on AP_INVOICES_ALL. Could you please help me to avoid this FTS as well ? Or is there a better way to reframe the query or a better approach ? (The original query was modified by me to avoid the FTS in the first part, and the attached one is a modified query).
SELECT ICH.CC_NUM , AIN.INVOICE_NUM , AIN.INVOICE_TYPE_LOOKUP_CODE ,
AAL.ENTERED_DR , AAL.ENTERED_CR , AAL.ACCOUNTED_DR , AAL.ACCOUNTED_CR ,
AAL.AE_LINE_ID , AAL.AE_LINE_NUMBER , AAL.AE_HEADER_ID ,
AAL.AE_LINE_TYPE_CODE , AAL.CODE_COMBINATION_ID AE_LINE_CCID ,
PDI.CODE_COMBINATION_ID PDI_CCID , PDI.BUDGET_ACCOUNT_ID ,
AEH.ACCOUNTING_DATE , AEH.PERIOD_NAME , AEH.CREATED_BY , 'STANDARD'
INVOICE_TYPE
FROM
IGC_CC_HEADERS ICH
, PO_HEADERS_ALL PHE
, PO_DISTRIBUTIONS_ALL PDI
, PO_VENDOR_SITES_ALL PVE
, AP_INVOICES_ALL AIN
, AP_INVOICE_DISTRIBUTIONS PRE
, AP_INVOICE_DISTRIBUTIONS STND
, AP_SYSTEM_PARAMETERS ASP
, AP_AE_LINES AAL
, AP_AE_HEADERS_ALL AEH
WHERE AIN.INVOICE_ID = STND.INVOICE_ID AND ICH.CC_NUM =
PHE.SEGMENT1 AND AAL.SOURCE_TABLE = 'AP_INVOICE_DISTRIBUTIONS' AND
AAL.SOURCE_ID = STND.INVOICE_DISTRIBUTION_ID AND
STND.PREPAY_DISTRIBUTION_ID=PRE.INVOICE_DISTRIBUTION_ID AND
AEH.GL_TRANSFER_FLAG='N' AND AEH.AE_HEADER_ID = AAL.AE_HEADER_ID AND
PVE.VENDOR_SITE_ID = PHE.VENDOR_SITE_ID AND PHE.PO_HEADER_ID =
PDI.PO_HEADER_ID AND PDI.PO_DISTRIBUTION_ID=PRE.PO_DISTRIBUTION_ID AND
AIN.INVOICE_TYPE_LOOKUP_CODE <> 'PREPAYMENT' AND (
(STND.DIST_CODE_COMBINATION_ID=ASP.PREPAY_CODE_COMBINATION_ID AND
NVL(PVE.PREPAY_CODE_COMBINATION_ID,-1)=-1 ) OR
STND.DIST_CODE_COMBINATION_ID = PVE.PREPAY_CODE_COMBINATION_ID )
UNION
SELECT ICH.CC_NUM , AIN.INVOICE_NUM , AIN.INVOICE_TYPE_LOOKUP_CODE ,
AAL.ENTERED_DR , AAL.ENTERED_CR , AAL.ACCOUNTED_DR , AAL.ACCOUNTED_CR ,
AAL.AE_LINE_ID , AAL.AE_LINE_NUMBER , AAL.AE_HEADER_ID ,
AAL.AE_LINE_TYPE_CODE , AAL.CODE_COMBINATION_ID AE_LINE_CCID ,
PDI.CODE_COMBINATION_ID PDI_CCID , PDI.BUDGET_ACCOUNT_ID ,
AEH.ACCOUNTING_DATE , AEH.PERIOD_NAME , AEH.CREATED_BY , 'PREPAY'
INVOICE_TYPE
FROM
IGC_CC_HEADERS ICH
, PO_HEADERS_ALL PHE
, PO_DISTRIBUTIONS_ALL PDI
, PO_VENDOR_SITES_ALL PVE
, AP_INVOICES_ALL AIN
, AP_INVOICE_DISTRIBUTIONS AID
, AP_SYSTEM_PARAMETERS ASP
, AP_AE_LINES AAL
, AP_AE_HEADERS_ALL AEH
WHERE
AIN.INVOICE_ID = AID.INVOICE_ID AND ICH.CC_NUM = PHE.SEGMENT1 AND
AAL.SOURCE_TABLE = 'AP_INVOICE_DISTRIBUTIONS' AND AAL.SOURCE_ID =
AID.INVOICE_DISTRIBUTION_ID AND AEH.GL_TRANSFER_FLAG='N' AND
AEH.AE_HEADER_ID = AAL.AE_HEADER_ID AND PVE.VENDOR_SITE_ID =
PHE.VENDOR_SITE_ID AND PHE.PO_HEADER_ID = PDI.PO_HEADER_ID AND
PDI.PO_DISTRIBUTION_ID = AID.PO_DISTRIBUTION_ID AND
AIN.INVOICE_TYPE_LOOKUP_CODE = 'PREPAYMENT' AND ( (
AID.DIST_CODE_COMBINATION_ID = ASP.PREPAY_CODE_COMBINATION_ID AND NVL(
PVE.PREPAY_CODE_COMBINATION_ID,-1) = -1 ) OR AID.DIST_CODE_COMBINATION_ID =
PVE.PREPAY_CODE_COMBINATION_ID ) ORDER BY INVOICE_NUM,INVOICE_TYPE
Thanks a lot,
Arun

When your query takes too long ...
Also you say it is a cursor, what kind, if it is a loop then these are just slow anyway and tuning the query is more or less pointless if you want it to go much faster.

Performance tuning of a customised Transaction Code which for interface

Hii All ,
I am new to performance tuning please guide me How to do performance tuning of Custom T-code through I am aware of all T-codes for performance tuning.
Please guide hoe to do it and what are basic need to before to start Performance tuning ?
Thanks
ABAP Pro
Moderator message: Please Read before Posting in the Performance and Tuning Forum
Locked by: Thomas Zloch on Jun 7, 2011 9:37 AM

I recommend :
1. use SQL tracing with DBMS_MONITOR and then TKPROF on raw SQL trace file
2. call the function as it used in your production environment
See good examples in http://www.oracle-base.com/articles/10g/SQLTrace10046TrcsessAndTkprof10g.php (just refer to DBMS_MONITOR examples and TKPROF).
Note that SQL trace will only trace SQL and not PL/SQL. If SQL elapsed time does not match function call elapsed time close enough, you need to use DBMS_PROFILER to know where PL/SQL non SQL code elapsed time is used.
I don't recommend using EXPLAIN PLAN because it has known limitations http://docs.oracle.com/cd/E11882_01/server.112/e16638/ex_plan.htm#PFGRF94673 (others have said "EXPLAIN PLAN lies" - you can google for this expression ....).
Edited by: P. Forstmann on 10 févr. 2012 19:44

Can Anybody Send Me The Latest Testking Pdf Of 1z0-033 (Performance Tuning

Hello,
Can Anybody Send Me The Latest Testking Pdf Of 1z0-033 (Performance Tuning
my email address is asiforacle [email protected]
Regards,
Asif Iqbal
Software Engineer. ( Karachi, Pakistan ).

The answer is surely NO but what I would like to ask for the sake of curiosity , why did you ask about Performance Tuning questions over Sql /Plsql forum , not on Database General Forum? Not that you should go there now and ask, just curious.
Tell you what, read the free book(yup free). Here it is,
http://download.oracle.com/docs/cd/B10501_01/server.920/a96533.pdf
You won't need anything else to read, not even that testking stuff too.
HTH
Aman....

Performance tuning of this code.

Hello Friends,
Following is the piece of Code.. can some one please help me to optimise the code.
I want to do performance tuning on the same.
Any inputs on this would be valuable to me .
Thanking you all in anticipation.
<< Unformatted code removed >>
Edited by: Jitesh Pamnani on Apr 7, 2009 10:09 AM
Edited by: Jitesh Pamnani on Apr 7, 2009 10:09 AM
Edited by: Rob Burbank on Apr 7, 2009 11:05 AM

please read,
SQL trace:
/people/siegfried.boes/blog/2007/09/05/the-sql-trace-st05-150-quick-and-easy
for the first part, without SQL Trace it does not make much sense, to check your select statements.
I guess that one or several are slow. But there are too many.
Second part, use sorted tables or binary search!!!!!
Your coding is highly nonlinear, not only quadratic but even cubic!!!!
Read here for table types and runtimes
Measurements on internal tables: Reads and Loops:
/people/siegfried.boes/blog/2007/09/12/runtimes-of-reads-and-loops-on-internal-tables
Read here about nonlinearity:
Nonlinearity: The problem and background
/people/siegfried.boes/blog/2007/02/12/performance-problems-caused-by-nonlinear-coding
Read here for measuring:
SE30
/people/siegfried.boes/blog/2007/11/13/the-abap-runtime-trace-se30--quick-and-easy
Z_SE30_COMPARE
/people/siegfried.boes/blog/2008/01/15/a-tool-to-compare-runtime-measurements-zse30compare
Nonlinearity Check
/people/siegfried.boes/blog/2008/01/24/nonlinearity-check-using-the-zse30compare
If you do ot all I assume that your coding can becomes faster by factors 10 ... 100 or even more.
Siegfried

Need clear steps for doing performance tuning on SQL Server 2008 R2 (DB Engine, Reporting Services and Integration Services)

We have to inverstigate about a reporting solution where things are getting slow (may be material, database design, network matters).
I have red a lot in MSDN and some books about performance tuning on SQL Server 2008 R2 (or other) but frankly, I feel a little lost in all that stuff
I'am looking for practical steps in order to do the tuning. Someone had like a recipe for that : a success story...
My (brain storm) Methodology should follow these steps:
Resource bottlenecks: CPU, memory, and I/O bottlenecks
tempdb bottlenecks
A slow-running user query : Missing indexes, statistics,...
Use performance counters : there are many, can one give us the list of the most important
how to do fine tuning about SQL Server configuration
SSRS, SSIS configuration ?
And do the recommandations.
Thanks
"there is no Royal Road to Mathematics, in other words, that I have only a very small head and must live with it..."
Edsger W. Dijkstra

Hello,
There is no clear defined step which can be categorized as step by step to performance tuning.Your first goal is to find out cause or drill down to factor causing slowness of SQL server it can be poorly written query ,missing indexes,outdated stats.RAM crunch
CPU crunch so on and so forth.
I generally refer to below doc for SQL server tuning
http://technet.microsoft.com/en-us/library/dd672789(v=sql.100).aspx
For SSIS tuning i refer below doc.
http://technet.microsoft.com/library/Cc966529#ECAA
http://msdn.microsoft.com/en-us/library/ms137622(v=sql.105).aspx
When I face issue i generally look at wait stats ,wait stats give you idea about on what resource query was waiting.
--By Jonathan KehayiasSELECT TOP 10
wait_type ,
max_wait_time_ms wait_time_ms ,
signal_wait_time_ms ,
wait_time_ms - signal_wait_time_ms AS resource_wait_time_ms ,
100.0 * wait_time_ms / SUM(wait_time_ms) OVER ( )
AS percent_total_waits ,
100.0 * signal_wait_time_ms / SUM(signal_wait_time_ms) OVER ( )
AS percent_total_signal_waits ,
100.0 * ( wait_time_ms - signal_wait_time_ms )
/ SUM(wait_time_ms) OVER ( ) AS percent_total_resource_waits
FROM sys.dm_os_wait_stats
WHERE wait_time_ms > 0 -- remove zero wait_time
AND wait_type NOT IN -- filter out additional irrelevant waits
( 'SLEEP_TASK', 'BROKER_TASK_STOP', 'BROKER_TO_FLUSH',
'SQLTRACE_BUFFER_FLUSH','CLR_AUTO_EVENT', 'CLR_MANUAL_EVENT',
'LAZYWRITER_SLEEP', 'SLEEP_SYSTEMTASK', 'SLEEP_BPOOL_FLUSH',
'BROKER_EVENTHANDLER', 'XE_DISPATCHER_WAIT', 'FT_IFTSHC_MUTEX',
'CHECKPOINT_QUEUE', 'FT_IFTS_SCHEDULER_IDLE_WAIT',
'BROKER_TRANSMITTER', 'FT_IFTSHC_MUTEX', 'KSOURCE_WAKEUP',
'LAZYWRITER_SLEEP', 'LOGMGR_QUEUE', 'ONDEMAND_TASK_QUEUE',
'REQUEST_FOR_DEADLOCK_SEARCH', 'XE_TIMER_EVENT', 'BAD_PAGE_PROCESS',
'DBMIRROR_EVENTS_QUEUE', 'BROKER_RECEIVE_WAITFOR',
'PREEMPTIVE_OS_GETPROCADDRESS', 'PREEMPTIVE_OS_AUTHENTICATIONOPS',
'WAITFOR', 'DISPATCHER_QUEUE_SEMAPHORE', 'XE_DISPATCHER_JOIN',
'RESOURCE_QUEUE' )
ORDER BY wait_time_ms DESC
use below link to analyze wait stats
http://www.sqlskills.com/blogs/paul/wait-statistics-or-please-tell-me-where-it-hurts/
HTH
PS: for reporting services you can post in SSRS forum
Please mark this reply as the answer or vote as helpful, as appropriate, to make it useful for other readers

SQL Performance tuning

Hello everybody,
I have a problem with an search application, users can search in different tables, those tables have an average off 15 million records. The users can add "search lines"
Here is an example off a search line typename = 'Project' attributename = 'name' value LIKE '%demo%'
When a user adds 3 or more search lines the application becomes slow.
Its running on a 10.2.0.10 and the hardware is not that important here, because it will change all the time because to search application will be installed on the intranet off different companies.
The problem will rise when alot off joins happen, I tried materialized views, its faster but the queries will be different all the time. So when alot off users will query and alot off materialized views are made it will maybe slow down the server.
Here is the example sql code that the application dynamically creates, does anyone have a suggestion to optimize this?
All the tables used in this query have indexes on all there columns, maybe to much indexes slows down the query?
SELECT q2.tbl_id
FROM
(SELECT tbl_search_attstring.tbl_id,
tbl_search_atttype.typename
FROM tbl_search_attstring,
tbl_search_atttype
WHERE tbl_search_attstring.typeid = tbl_search_atttype.typeid
AND typename = 'Project'
AND attributename = 'name'
AND LOWER(VALUE) LIKE '%demo%')
q1,
(SELECT tbl_search_attstring.tbl_id,
tbl_search_atttype.typename
FROM tbl_search_attstring,
tbl_search_atttype
WHERE tbl_search_attstring.typeid = tbl_search_atttype.typeid
AND typename = 'Section'
AND attributename = 'name'
AND LOWER(VALUE) LIKE '%section%')
q2,
(SELECT tbl_search_attstring.tbl_id
FROM tbl_search_attstring,
tbl_search_atttype
WHERE tbl_search_attstring.typeid = tbl_search_atttype.typeid
AND typename = 'Dir'
AND attributename = 'default label'
AND LOWER(VALUE) LIKE '%a%')
q3,
tbl_relationship rel
WHERE q1.tbl_id = rel.parent
AND q3.tbl_id = rel.parent
AND rel.child = q2.tbl_id
Thanks in advance!

Hi,
My suggestion is you should create your query dynamically by pl/sql.
On the other hand pls try this;
SELECT q2.tbl_id
FROM
(SELECT tbl_search_attstring.tbl_id,
tbl_search_atttype.typename
FROM tbl_search_attstring,
tbl_search_atttype
WHERE tbl_search_attstring.typeid = tbl_search_atttype.typeid
AND typename in ('Project','Dir')
AND attributename in( 'name','default label')
AND LOWER(VALUE) LIKE '%demo%' or LOWER(VALUE) LIKE '%a%')
q13,
(SELECT tbl_search_attstring.tbl_id,
tbl_search_atttype.typename
FROM tbl_search_attstring,
tbl_search_atttype
WHERE tbl_search_attstring.typeid = tbl_search_atttype.typeid
AND typename = 'Section'
AND attributename = 'name'
AND LOWER(VALUE) LIKE '%section%')
q2,
tbl_relationship rel
WHERE q13.tbl_id = rel.parent
AND rel.child = q2.tbl_id
BR...
efe

Performance degradation in pl/sql parsing

We are trying to use xml pl/sql parser and noticed performance degradation as we run multiple times. We zeroed into the following clause:
doc := xmlparser.getDocument(p);
The first time the procedure is run the elapsed time at sqlplus is something like .45sec, but as we run repeatedly in the same session the elapsed time keeps on increasing by .02 seconds. If we log out and start fresh, we start again from .45sec.
We noticed similar degradation with
p := xmlparser.newParser;
but we got around by making the 'p' variable as package variable, initializing it once and using the same for all invocations.
Any suggestions?
Thank you.

Can I enhance the PL/SQL code for better performance ? Probably you can enhance it.
or, is this OK to take so long to process these many rows? It should take a few minutes, not several hours.
But please provide some more details like your database version etc.
I suggest to TRACE the session that executes the PL/SQL code, with WAIT events, so you'll see where and on what time is spent, you'll identify your 'problem statements very quickly' (after you or your DBA have TKPROF'ed the trace file).
SQL> alter session set events '10046 trace name context forever, level 12';
SQL> execute your PL/SQL code here
SQL> exitWill give you a .trc file in your udump directory on the server.
http://www.oracle-base.com/articles/10g/SQLTrace10046TrcsessAndTkprof10g.php
Also this informative thread can give you more ideas:
HOW TO: Post a SQL statement tuning request - template posting
as well as doing a search on 10046 at AskTom, http://asktom.oracle.com will give you more examples.
and reading Oracle's Performance Tuning Guide: http://www.oracle.com/pls/db102/to_toc?pathname=server.102%2Fb14211%2Ftoc.htm&remark=portal+%28Getting+Started%29

Performance tuning in t

hi,
I have to do perofrmance for one program, it is taking 67000 secs in back ground for execution and 1000 secs for some varints .It is an ALV report.
please suggest me how to proced to change the code.

Performance tuning for Data Selection Statement
http://www.sap-img.com/abap/performance-tuning-for-data-selection-statement.htmDebugger
http://help.sap.com/saphelp_47x200/helpdata/en/c6/617ca9e68c11d2b2ab080009b43351/content.htm
http://www.cba.nau.edu/haney-j/CIS497/Assignments/Debugging.doc
http://help.sap.com/saphelp_erp2005/helpdata/en/b3/d322540c3beb4ba53795784eebb680/frameset.htm
Run Time Analyser
http://help.sap.com/saphelp_47x200/helpdata/en/c6/617cafe68c11d2b2ab080009b43351/content.htm
SQL trace
http://help.sap.com/saphelp_47x200/helpdata/en/d1/801f7c454211d189710000e8322d00/content.htm
CATT - Computer Aided Testing Too
http://help.sap.com/saphelp_47x200/helpdata/en/b3/410b37233f7c6fe10000009b38f936/frameset.htm
Test Workbench
http://help.sap.com/saphelp_47x200/helpdata/en/a8/157235d0fa8742e10000009b38f889/frameset.htm
Coverage Analyser
http://help.sap.com/saphelp_47x200/helpdata/en/c7/af9a79061a11d4b3d4080009b43351/content.htm
Runtime Monitor
http://help.sap.com/saphelp_47x200/helpdata/en/b5/fa121cc15911d5993d00508b6b8b11/content.htm
Memory Inspector
http://help.sap.com/saphelp_47x200/helpdata/en/a2/e5fc84cc87964cb2c29f584152d74e/content.htm
ECATT - Extended Computer Aided testing tool.
http://help.sap.com/saphelp_47x200/helpdata/en/20/e81c3b84e65e7be10000000a11402f/frameset.htm
Just refer to these links...
performance
Performance
Performance Guide
performance issues...
Performance Tuning
Performance issues
performance tuning
performance tuning
You can go to the transaction SE30 to have the runtime analysis of your program.Also try the transaction SCI , which is SAP Code Inspector.

How to avoid performance problems in PL/SQL?

How to avoid performance problems in PL/SQL?
As per my knowledge, below some points to avoid performance proble in PL/SQL.
Is there other point to avoid performance problems?
1. Use FORALL instead of FOR, and use BULK COLLECT to avoid looping many times.
2. EXECUTE IMMEDIATE is faster than DBMS_SQL
3. Use NOCOPY for OUT and IN OUT if the original value need not be retained. Overhead of keeping a copy of OUT is avoided.

Susil Kumar Nagarajan wrote:
1. Group no of functions or procedures into a PACKAGEPutting related functions and procedures into packages is useful from a code organization standpoint. It has nothing whatsoever to do with performance.
2. Good to use collections in place of cursors that do DML operations on large set of recordsBut using SQL is more efficient than using PL/SQL with bulk collects.
4. Optimize SQL statements if they need to
-> Avoid using IN, NOT IN conditions or those cause full table scans in queriesThat is not true.
-> See to queries they use Indexes properly , sometimes Leading index column is missed out that cause performance overheadAssuming "properly" implies that it is entirely possible that a table scan is more efficient than using an index.
5. use Oracle HINTS if query can't be further tuned and hints can considerably help youHints should be used only as a last resort. It is almost certainly the case that if you can use a hint that forces a particular plan to improve performance that there is some problem in the underlying statistics that should be fixed in order to resolve issues with many queries rather than just the one you're looking at.
Justin

Performance Tuning Tips

Dear All,
In our project we are facing lot of problems with the Performance, users are compaining about the poor performance of the few reports and all, we are in the process of fine tuning the reports by following the all methods/suggestions provided by SAP ( like removing the select queries from Loops, For all entries , Binary serach etc )
But still I want to know from you people what can we check from BASIS percpective ( all the settings ) and also ABAP percpective to improve the performance.
And also I have one more query that what is " Table Statistics " , what is the use of this ...
Please give ur valueble suggestions to us in improving the performance .
Thanks in Advance !

Hi
Ways of Performance Tuning
1. Selection Criteria
2. Select Statements
 Select Queries
 SQL Interface
 Aggregate Functions
 For all Entries
Select Over more than one Internal table
Selection Criteria
1. Restrict the data to the selection criteria itself, rather than filtering it out using the ABAP code using CHECK statement.
2. Select with selection list.
Points # 1/2
SELECT * FROM SBOOK INTO SBOOK_WA.
CHECK: SBOOK_WA-CARRID = 'LH' AND
 SBOOK_WA-CONNID = '0400'.
ENDSELECT.
The above code can be much more optimized by the code written below which avoids CHECK, selects with selection list
SELECT CARRID CONNID FLDATE BOOKID FROM SBOOK INTO TABLE T_SBOOK
WHERE SBOOK_WA-CARRID = 'LH' AND
 SBOOK_WA-CONNID = '0400'.
Select Statements Select Queries
1. Avoid nested selects
2. Select all the records in a single shot using into table clause of select statement rather than to use Append statements.
3. When a base table has multiple indices, the where clause should be in the order of the index, either a primary or a secondary index.
4. For testing existence , use Select.. Up to 1 rows statement instead of a Select-Endselect-loop with an Exit.
5. Use Select Single if all primary key fields are supplied in the Where condition .
Point # 1
SELECT * FROM EKKO INTO EKKO_WA.
SELECT * FROM EKAN INTO EKAN_WA
 WHERE EBELN = EKKO_WA-EBELN.
ENDSELECT.
ENDSELECT.
The above code can be much more optimized by the code written below.
SELECT PF1 PF2 FF3 FF4 INTO TABLE ITAB
 FROM EKKO AS P INNER JOIN EKAN AS F
 ON PEBELN = FEBELN.
Note: A simple SELECT loop is a single database access whose result is passed to the ABAP program line by line. Nested SELECT loops mean that the number of accesses in the inner loop is multiplied by the number of accesses in the outer loop. One should therefore use nested SELECT loops only if the selection in the outer loop contains very few lines or the outer loop is a SELECT SINGLE statement.
Point # 2
SELECT * FROM SBOOK INTO SBOOK_WA.
CHECK: SBOOK_WA-CARRID = 'LH' AND
 SBOOK_WA-CONNID = '0400'.
ENDSELECT.
The above code can be much more optimized by the code written below which avoids CHECK, selects with selection list and puts the data in one shot using into table
SELECT CARRID CONNID FLDATE BOOKID FROM SBOOK INTO TABLE T_SBOOK
WHERE SBOOK_WA-CARRID = 'LH' AND
 SBOOK_WA-CONNID = '0400'.
Point # 3
To choose an index, the optimizer checks the field names specified in the where clause and then uses an index that has the same order of the fields . In certain scenarios, it is advisable to check whether a new index can speed up the performance of a program. This will come handy in programs that access data from the finance tables.
Point # 4
SELECT * FROM SBOOK INTO SBOOK_WA
UP TO 1 ROWS
WHERE CARRID = 'LH'.
ENDSELECT.
The above code is more optimized as compared to the code mentioned below for testing existence of a record.
SELECT * FROM SBOOK INTO SBOOK_WA
 WHERE CARRID = 'LH'.
EXIT.
ENDSELECT.
Point # 5
If all primary key fields are supplied in the Where condition you can even use Select Single.
Select Single requires one communication with the database system, whereas Select-Endselect needs two.
Select Statements contd.. SQL Interface
1. Use column updates instead of single-row updates
to update your database tables.
2. For all frequently used Select statements, try to use an index.
3. Using buffered tables improves the performance considerably.
Point # 1
SELECT * FROM SFLIGHT INTO SFLIGHT_WA.
SFLIGHT_WA-SEATSOCC =
 SFLIGHT_WA-SEATSOCC - 1.
UPDATE SFLIGHT FROM SFLIGHT_WA.
ENDSELECT.
The above mentioned code can be more optimized by using the following code
UPDATE SFLIGHT
 SET SEATSOCC = SEATSOCC - 1.
Point # 2
SELECT * FROM SBOOK CLIENT SPECIFIED INTO SBOOK_WA
WHERE CARRID = 'LH'
 AND CONNID = '0400'.
ENDSELECT.
The above mentioned code can be more optimized by using the following code
SELECT * FROM SBOOK CLIENT SPECIFIED INTO SBOOK_WA
WHERE MANDT IN ( SELECT MANDT FROM T000 )
 AND CARRID = 'LH'
 AND CONNID = '0400'.
ENDSELECT.
Point # 3
Bypassing the buffer increases the network considerably
SELECT SINGLE * FROM T100 INTO T100_WA
BYPASSING BUFFER
WHERE SPRSL = 'D'
 AND ARBGB = '00'
 AND MSGNR = '999'.
The above mentioned code can be more optimized by using the following code
SELECT SINGLE * FROM T100 INTO T100_WA
WHERE SPRSL = 'D'
 AND ARBGB = '00'
 AND MSGNR = '999'.
Select Statements contd Aggregate Functions
 If you want to find the maximum, minimum, sum and average value or the count of a database column, use a select list with aggregate functions instead of computing the aggregates yourself.
Some of the Aggregate functions allowed in SAP are MAX, MIN, AVG, SUM, COUNT, COUNT( * )
Consider the following extract.
 Maxno = 0.
 Select * from zflight where airln = LF and cntry = IN.
 Check zflight-fligh > maxno.
 Maxno = zflight-fligh.
 Endselect.
The above mentioned code can be much more optimized by using the following code.
Select max( fligh ) from zflight into maxno where airln = LF and cntry = IN.
Select Statements contdFor All Entries
 The for all entries creates a where clause, where all the entries in the driver table are combined with OR. If the number of entries in the driver table is larger than rsdb/max_blocking_factor, several similar SQL statements are executed to limit the length of the WHERE clause.
 The plus
 Large amount of data
 Mixing processing and reading of data
 Fast internal reprocessing of data
 Fast
 The Minus
 Difficult to program/understand
 Memory could be critical (use FREE or PACKAGE size)
Points to be must considered FOR ALL ENTRIES Check that data is present in the driver table
 Sorting the driver table
 Removing duplicates from the driver table
Consider the following piece of extract
Loop at int_cntry.
 Select single * from zfligh into int_fligh
where cntry = int_cntry-cntry.
Append int_fligh.
Endloop.
The above mentioned can be more optimized by using the following code.
Sort int_cntry by cntry.
Delete adjacent duplicates from int_cntry.
If NOT int_cntry[] is INITIAL.
 Select * from zfligh appending table int_fligh
 For all entries in int_cntry
 Where cntry = int_cntry-cntry.
Endif.
Select Statements contd Select Over more than one Internal table
1. Its better to use a views instead of nested Select statements.
2. To read data from several logically connected tables use a join instead of nested Select statements. Joins are preferred only if all the primary key are available in WHERE clause for the tables that are joined. If the primary keys are not provided in join the Joining of tables itself takes time.
3. Instead of using nested Select loops it is often better to use subqueries.
Point # 1
SELECT * FROM DD01L INTO DD01L_WA
WHERE DOMNAME LIKE 'CHAR%'
 AND AS4LOCAL = 'A'.
SELECT SINGLE * FROM DD01T INTO DD01T_WA
 WHERE DOMNAME = DD01L_WA-DOMNAME
 AND AS4LOCAL = 'A'
 AND AS4VERS = DD01L_WA-AS4VERS
 AND DDLANGUAGE = SY-LANGU.
ENDSELECT.
The above code can be more optimized by extracting all the data from view DD01V_WA
SELECT * FROM DD01V INTO DD01V_WA
WHERE DOMNAME LIKE 'CHAR%'
 AND DDLANGUAGE = SY-LANGU.
ENDSELECT
Point # 2
SELECT * FROM EKKO INTO EKKO_WA.
SELECT * FROM EKAN INTO EKAN_WA
 WHERE EBELN = EKKO_WA-EBELN.
ENDSELECT.
ENDSELECT.
The above code can be much more optimized by the code written below.
SELECT PF1 PF2 FF3 FF4 INTO TABLE ITAB
 FROM EKKO AS P INNER JOIN EKAN AS F
 ON PEBELN = FEBELN.
Point # 3
SELECT * FROM SPFLI
INTO TABLE T_SPFLI
WHERE CITYFROM = 'FRANKFURT'
 AND CITYTO = 'NEW YORK'.
SELECT * FROM SFLIGHT AS F
 INTO SFLIGHT_WA
 FOR ALL ENTRIES IN T_SPFLI
 WHERE SEATSOCC < F~SEATSMAX
 AND CARRID = T_SPFLI-CARRID
 AND CONNID = T_SPFLI-CONNID
 AND FLDATE BETWEEN '19990101' AND '19990331'.
ENDSELECT.
The above mentioned code can be even more optimized by using subqueries instead of for all entries.
SELECT * FROM SFLIGHT AS F INTO SFLIGHT_WA
 WHERE SEATSOCC < F~SEATSMAX
 AND EXISTS ( SELECT * FROM SPFLI
 WHERE CARRID = F~CARRID
 AND CONNID = F~CONNID
 AND CITYFROM = 'FRANKFURT'
 AND CITYTO = 'NEW YORK' )
 AND FLDATE BETWEEN '19990101' AND '19990331'.
ENDSELECT.
Internal Tables
1. Table operations should be done using explicit work areas rather than via header lines.
2. Always try to use binary search instead of linear search. But dont forget to sort your internal table before that.
3. A dynamic key access is slower than a static one, since the key specification must be evaluated at runtime.
4. A binary search using secondary index takes considerably less time.
5. LOOP ... WHERE is faster than LOOP/CHECK because LOOP ... WHERE evaluates the specified condition internally.
6. Modifying selected components using MODIFY itab TRANSPORTING f1 f2.. accelerates the task of updating a line of an internal table.
Point # 2
READ TABLE ITAB INTO WA WITH KEY K = 'X BINARY SEARCH.
IS MUCH FASTER THAN USING
READ TABLE ITAB INTO WA WITH KEY K = 'X'.
If TAB has n entries, linear search runs in O( n ) time, whereas binary search takes only O( log2( n ) ).
Point # 3
READ TABLE ITAB INTO WA WITH KEY K = 'X'. IS FASTER THAN USING
READ TABLE ITAB INTO WA WITH KEY (NAME) = 'X'.
Point # 5
LOOP AT ITAB INTO WA WHERE K = 'X'.
ENDLOOP.
The above code is much faster than using
LOOP AT ITAB INTO WA.
CHECK WA-K = 'X'.
ENDLOOP.
Point # 6
WA-DATE = SY-DATUM.
MODIFY ITAB FROM WA INDEX 1 TRANSPORTING DATE.
The above code is more optimized as compared to
WA-DATE = SY-DATUM.
MODIFY ITAB FROM WA INDEX 1.
7. Accessing the table entries directly in a "LOOP ... ASSIGNING ..." accelerates the task of updating a set of lines of an internal table considerably
8. If collect semantics is required, it is always better to use to COLLECT rather than READ BINARY and then ADD.
9. "APPEND LINES OF itab1 TO itab2" accelerates the task of appending a table to another table considerably as compared to LOOP-APPEND-ENDLOOP.
10. DELETE ADJACENT DUPLICATES accelerates the task of deleting duplicate entries considerably as compared to READ-LOOP-DELETE-ENDLOOP.
11. "DELETE itab FROM ... TO ..." accelerates the task of deleting a sequence of lines considerably as compared to DO -DELETE-ENDDO.
Point # 7
Modifying selected components only makes the program faster as compared to Modifying all lines completely.
e.g,
LOOP AT ITAB ASSIGNING <WA>.
I = SY-TABIX MOD 2.
IF I = 0.
 <WA>-FLAG = 'X'.
ENDIF.
ENDLOOP.
The above code works faster as compared to
LOOP AT ITAB INTO WA.
I = SY-TABIX MOD 2.
IF I = 0.
 WA-FLAG = 'X'.
 MODIFY ITAB FROM WA.
ENDIF.
ENDLOOP.
Point # 8
LOOP AT ITAB1 INTO WA1.
READ TABLE ITAB2 INTO WA2 WITH KEY K = WA1-K BINARY SEARCH.
IF SY-SUBRC = 0.
 ADD: WA1-VAL1 TO WA2-VAL1,
 WA1-VAL2 TO WA2-VAL2.
 MODIFY ITAB2 FROM WA2 INDEX SY-TABIX TRANSPORTING VAL1 VAL2.
ELSE.
 INSERT WA1 INTO ITAB2 INDEX SY-TABIX.
ENDIF.
ENDLOOP.
The above code uses BINARY SEARCH for collect semantics. READ BINARY runs in O( log2(n) ) time. The above piece of code can be more optimized by
LOOP AT ITAB1 INTO WA.
COLLECT WA INTO ITAB2.
ENDLOOP.
SORT ITAB2 BY K.
COLLECT, however, uses a hash algorithm and is therefore independent
of the number of entries (i.e. O(1)) .
Point # 9
APPEND LINES OF ITAB1 TO ITAB2.
This is more optimized as compared to
LOOP AT ITAB1 INTO WA.
APPEND WA TO ITAB2.
ENDLOOP.
Point # 10
DELETE ADJACENT DUPLICATES FROM ITAB COMPARING K.
This is much more optimized as compared to
READ TABLE ITAB INDEX 1 INTO PREV_LINE.
LOOP AT ITAB FROM 2 INTO WA.
IF WA = PREV_LINE.
 DELETE ITAB.
ELSE.
 PREV_LINE = WA.
ENDIF.
ENDLOOP.
Point # 11
DELETE ITAB FROM 450 TO 550.
This is much more optimized as compared to
DO 101 TIMES.
DELETE ITAB INDEX 450.
ENDDO.
12. Copying internal tables by using ITAB2[ ] = ITAB1[ ] as compared to LOOP-APPEND-ENDLOOP.
13. Specify the sort key as restrictively as possible to run the program faster.
Point # 12
ITAB2[] = ITAB1[].
This is much more optimized as compared to
REFRESH ITAB2.
LOOP AT ITAB1 INTO WA.
APPEND WA TO ITAB2.
ENDLOOP.
Point # 13SORT ITAB BY K. makes the program runs faster as compared to SORT ITAB.
Internal Tables contd
Hashed and Sorted tables
1. For single read access hashed tables are more optimized as compared to sorted tables.
2. For partial sequential access sorted tables are more optimized as compared to hashed tables
Hashed And Sorted Tables
Point # 1
Consider the following example where HTAB is a hashed table and STAB is a sorted table
DO 250 TIMES.
N = 4 * SY-INDEX.
READ TABLE HTAB INTO WA WITH TABLE KEY K = N.
IF SY-SUBRC = 0.
ENDIF.
ENDDO.
This runs faster for single read access as compared to the following same code for sorted table
DO 250 TIMES.
N = 4 * SY-INDEX.
READ TABLE STAB INTO WA WITH TABLE KEY K = N.
IF SY-SUBRC = 0.
ENDIF.
ENDDO.
Point # 2
Similarly for Partial Sequential access the STAB runs faster as compared to HTAB
LOOP AT STAB INTO WA WHERE K = SUBKEY.
ENDLOOP.
This runs faster as compared to
LOOP AT HTAB INTO WA WHERE K = SUBKEY.
ENDLOOP.
Reward if usefull

Performance tuning techniques

I am looking to compile a list of the major performance tuning techniques that can be implemented in an ABAP program.
Appreciate any feedback
J

HI,
chk this.
http://www.erpgenie.com/abap/performance.htm
http://www.thespot4sap.com/Articles/SAPABAPPerformanceTuning_PerformanceAnalysisTools.asp
http://www.sap-img.com/abap/performance-tuning-for-data-selection-statement.htm
Performance tuning for Data Selection Statement
For all entries
The for all entries creates a where clause, where all the entries in the driver table are combined with OR. If the number of
entries in the driver table is larger than rsdb/max_blocking_factor, several similar SQL statements are executed to limit the
length of the WHERE clause.
The plus
Large amount of data
Mixing processing and reading of data
Fast internal reprocessing of data
Fast
The Minus
Difficult to program/understand
Memory could be critical (use FREE or PACKAGE size)
Some steps that might make FOR ALL ENTRIES more efficient:
Removing duplicates from the the driver table
Sorting the driver table
If possible, convert the data in the driver table to ranges so a BETWEEN statement is used instead of and OR statement:
FOR ALL ENTRIES IN i_tab
WHERE mykey >= i_tab-low and
 mykey <= i_tab-high.
Nested selects
The plus:
Small amount of data
Mixing processing and reading of data
Easy to code - and understand
The minus:
Large amount of data
when mixed processing isnt needed
Performance killer no. 1
Select using JOINS
The plus
Very large amount of data
Similar to Nested selects - when the accesses are planned by the programmer
In some cases the fastest
Not so memory critical
The minus
Very difficult to program/understand
Mixing processing and reading of data not possible
Use the selection criteria
SELECT * FROM SBOOK.
CHECK: SBOOK-CARRID = 'LH' AND
 SBOOK-CONNID = '0400'.
ENDSELECT.
SELECT * FROM SBOOK
WHERE CARRID = 'LH' AND
 CONNID = '0400'.
ENDSELECT.
Use the aggregated functions
C4A = '000'.
SELECT * FROM T100
WHERE SPRSL = 'D' AND
 ARBGB = '00'.
CHECK: T100-MSGNR > C4A.
C4A = T100-MSGNR.
ENDSELECT.
SELECT MAX( MSGNR ) FROM T100 INTO C4A
WHERE SPRSL = 'D' AND
 ARBGB = '00'.
Select with view
SELECT * FROM DD01L
WHERE DOMNAME LIKE 'CHAR%'
 AND AS4LOCAL = 'A'.
SELECT SINGLE * FROM DD01T
 WHERE DOMNAME = DD01L-DOMNAME
 AND AS4LOCAL = 'A'
 AND AS4VERS = DD01L-AS4VERS
 AND DDLANGUAGE = SY-LANGU.
ENDSELECT.
SELECT * FROM DD01V
WHERE DOMNAME LIKE 'CHAR%'
 AND DDLANGUAGE = SY-LANGU.
ENDSELECT.
Select with index support
SELECT * FROM T100
WHERE ARBGB = '00'
 AND MSGNR = '999'.
ENDSELECT.
SELECT * FROM T002.
SELECT * FROM T100
 WHERE SPRSL = T002-SPRAS
 AND ARBGB = '00'
 AND MSGNR = '999'.
ENDSELECT.
ENDSELECT.
Select Into table
REFRESH X006.
SELECT * FROM T006 INTO X006.
APPEND X006.
ENDSELECT
SELECT * FROM T006 INTO TABLE X006.
Select with selection list
SELECT * FROM DD01L
WHERE DOMNAME LIKE 'CHAR%'
 AND AS4LOCAL = 'A'.
ENDSELECT
SELECT DOMNAME FROM DD01L
INTO DD01L-DOMNAME
WHERE DOMNAME LIKE 'CHAR%'
 AND AS4LOCAL = 'A'.
ENDSELECT
Key access to multiple lines
LOOP AT TAB.
CHECK TAB-K = KVAL.
ENDLOOP.
LOOP AT TAB WHERE K = KVAL.
ENDLOOP.
Copying internal tables
REFRESH TAB_DEST.
LOOP AT TAB_SRC INTO TAB_DEST.
APPEND TAB_DEST.
ENDLOOP.
TAB_DEST[] = TAB_SRC[].
Modifying a set of lines
LOOP AT TAB.
IF TAB-FLAG IS INITIAL.
 TAB-FLAG = 'X'.
ENDIF.
MODIFY TAB.
ENDLOOP.
TAB-FLAG = 'X'.
MODIFY TAB TRANSPORTING FLAG
 WHERE FLAG IS INITIAL.
Deleting a sequence of lines
DO 101 TIMES.
DELETE TAB_DEST INDEX 450.
ENDDO.
DELETE TAB_DEST FROM 450 TO 550.
Linear search vs. binary
READ TABLE TAB WITH KEY K = 'X'.
READ TABLE TAB WITH KEY K = 'X' BINARY SEARCH.
Comparison of internal tables
DESCRIBE TABLE: TAB1 LINES L1,
 TAB2 LINES L2.
IF L1 <> L2.
TAB_DIFFERENT = 'X'.
ELSE.
TAB_DIFFERENT = SPACE.
LOOP AT TAB1.
 READ TABLE TAB2 INDEX SY-TABIX.
 IF TAB1 <> TAB2.
 TAB_DIFFERENT = 'X'. EXIT.
 ENDIF.
ENDLOOP.
ENDIF.
IF TAB_DIFFERENT = SPACE.
ENDIF.
IF TAB1[] = TAB2[].
ENDIF.
Modify selected components
LOOP AT TAB.
TAB-DATE = SY-DATUM.
MODIFY TAB.
ENDLOOP.
WA-DATE = SY-DATUM.
LOOP AT TAB.
MODIFY TAB FROM WA TRANSPORTING DATE.
ENDLOOP.
Appending two internal tables
LOOP AT TAB_SRC.
APPEND TAB_SRC TO TAB_DEST.
ENDLOOP
APPEND LINES OF TAB_SRC TO TAB_DEST.
Deleting a set of lines
LOOP AT TAB_DEST WHERE K = KVAL.
DELETE TAB_DEST.
ENDLOOP
DELETE TAB_DEST WHERE K = KVAL.
Tools available in SAP to pin-point a performance problem
The runtime analysis (SE30)
SQL Trace (ST05)
Tips and Tricks tool
The performance database
Optimizing the load of the database
Using table buffering
Using buffered tables improves the performance considerably. Note that in some cases a stament can not be used with a buffered table, so when using these staments the buffer will be bypassed. These staments are:
Select DISTINCT
ORDER BY / GROUP BY / HAVING clause
Any WHERE clasuse that contains a subquery or IS NULL expression
JOIN s
A SELECT... FOR UPDATE
If you wnat to explicitly bypass the bufer, use the BYPASS BUFFER addition to the SELECT clause.
Use the ABAP SORT Clause Instead of ORDER BY
The ORDER BY clause is executed on the database server while the ABAP SORT statement is executed on the application server. The datbase server will usually be the bottleneck, so sometimes it is better to move thje sort from the datsbase server to the application server.
If you are not sorting by the primary key ( E.g. using the ORDER BY PRIMARY key statement) but are sorting by another key, it could be better to use the ABAP SORT stament to sort the data in an internal table. Note however that for very large result sets it might not be a feasible solution and you would want to let the datbase server sort it.
Avoid ther SELECT DISTINCT Statement
As with the ORDER BY clause it could be better to avoid using SELECT DISTINCT, if some of the fields are not part of an index. Instead use ABAP SORT + DELETE ADJACENT DUPLICATES on an internal table, to delete duplciate rows.
Regds
Anver
if hlped pls mark points

Performance tuning in PL/SQL code

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