SQL Performance Tuning process

Hi All,
Recently one interviewer asked me one question, saying user complain performance issue during query execution on Production Database, how will you start your analysis (step by step). Why there is performance issue. considering below point.
1. Production Database you do not have system table / Oracle Data Dictionary access. (Very limited acces, only you have table/view read permision).
2. Without dusturbing DBA.
I answered ,
1) by generating explain plan, to see what is the bottle neck for that query. (in any query opmization requred by using hint / query re write etc)
2) by looking when table / index was last analyze.
3) asking AWR report from DBA etc.
He was not satisfied. Request you all can you please help me on this by consedering all those constraints.
Thanks in Advance.
RK

885137 wrote:
Hi All,
Recently one interviewer asked me one question, saying user complain performance issue during query execution on Production Database, how will you start your analysis (step by step). Why there is performance issue. considering below point.
1. Production Database you do not have system table / Oracle Data Dictionary access. (Very limited acces, only you have table/view read permision).
2. Without dusturbing DBA.
I answered ,
1) by generating explain plan, to see what is the bottle neck for that query. (in any query opmization requred by using hint / query re write etc)
2) by looking when table / index was last analyze.
3) asking AWR report from DBA etc.
He was not satisfied. Request you all can you please help me on this by consedering all those constraints.
Thanks in Advance.
RK
He asked you a question that you could not answer it specifically, everything is solved on the spot, your answers are quite normal to the question. You asked why He was not satisfied? What are the reasons?
Ramin Hashimzade

Similar Messages

Help ! SQL Performance Tuning

Hi,
I am having following three sql statements. I am using Oracle 8i.
====================================================================================================================
Statement1 : Insert
Insert Into DBSchema.DstTableName( dstCol1, dstColP, dstColKey, dstCol2, dstCol3, dstCol4, dstCol5, dstCol6 )
( SELECT DbSchema.Seq.nextval, srColP, srColKey, srCol1, srCol2, nvl(srCol3,0), nvl(srCol4,0), SYSDATE
From
SrcTableName SRC
Where
srcColP IS NOT NULL AND
NOT EXISTS
(SELECT 1
From
DBSchema.DstTableName Dst
Where
SRC.srcColP = DST.dstColP AND SRC.srcColKey = DST.dstColKey )
====================================================================================================================
Statement2 : Update
Update DBSchema.DstTableName dst
SET ( dstCol1,dstCol2,dstCol3,dstCol4, dstCol5)
=
( SELECT srCol1, srCol2, nvl(srCol3,0), nvl(srCol4,0), SYSDATE
From
SrcTableName src
Where
src.srcColP = dst.dstColP AND SRC.srcColKey = DST.dstColKey
WHERE EXISTS (
SELECT
1
From
SrcTableName SRC
Where
SRC.srcColP = DST.dstColP AND SRC.srcColKey = DST.dstColKey ) ;
====================================================================================================================
Statement3 : Delete
Delete
FROM DBSchema.DstTableName DST
Where Exists (
SELECT
1
From
SrcTableName SRC
Where
src.srcColP = dst.dstColP )
AND NOT EXISTS
SELECT
1
From
SrcTableName SRC
Where
src.srcColP = dst.dstColP AND SRC.srcColKey = DST.dstColKey ) ;
====================================================================================================================
For the above three statement I have written the following procedure with cursor.
Equivalent Cursor:
PROCEDURE DEMOPROC
is
loop_Count integer := 0;
insert_Count integer := 0;
CURSOR c1
IS
SELECT src.srcCol1,
src.srcCol2,
src.srcCol3,
src.srcCol4,
src.srcCol5,
src.srcCol6,
src.srcCol7,
src.srcCol8,
src.srcCol9,
src.srcColKey,
src.srcColP
FROM
SrcTableName SRC
Where src.srcColP IS NOT NULL
AND NOT EXISTS
(SELECT 1
From
DBSchema.DstTableName Dst
Where
src.srcColP = DST.dstColP AND src.srcColKey = DST.dstColKey )
BEGIN
FOR r1 in c1 LOOP
Insert Into DBSchema.DstTableName( dstCol1, dstColP, dstColKey, dstCol2, dstCol3, dstCol4, dstCol5, dstCol6 )
values(DBSchema.Seq.nextval, r1.srcColP, r1.srcColKey, r1.srcCol1, r1.srcCol2, nvl(r1.srcCol3,0), nvl(r1.srcCol4,0), SYSDATE);
Update DBSchema.DstTableName dst
SET dst.dstCol1=r1.srcCol1 , dst.dstCol2=r1.srcCol2,
dst.dstCol3=nvl(r1.srcCol3,0),
dst.dstCol4=nvl(r1.srcCol4,0),
dst.dstCol5=SYSDATE
Where
r1.srcColP = dst.dstColP
AND
r1.srcColKey = DST.dstColKey ;
Delete
FROM DBSchema.DstTableName DST
Where
r1.srcColP = dst.dstColP ;
insert_Count := insert_Count + 1 ;
/* commit on a pre-defined interval */
if loop_Count > 999
then begin
commit;
loop_Count := 0;
end;
else loop_Count := loop_Count + 1;
end if;
end loop;
/* once the loop ends, commit and display the total number of records inserted */
commit;
dbms_output.put_line('total rows processed: '||TO_CHAR(insert_Count)); /*display insert count*/
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE('Error '||TO_CHAR(SQLCODE)||': '||SQLERRM);
END;
====================================================================================================================
I am not sure whether this cursor is right or not, have to verify it.
In delete and insert statements there is same where not exist clause in the original statement so I included that in my cursor declaration but not sure whether update will work with that or not.
I have to use the three statements mentioned above for few source and destination tables and each are having many rows. How do i tune it ?
What else can be done to improve the performance with the the three statements mentioned above.
Any help will be highly appreciated.
Thanks !
Regards,

Hi Tom,
Thanks for replying.
I tried three statement seperately.
As seen in my problem statement I am moving data from one table to another. Like this there are 50 tables. One of my procedure reads the source and destination table and creates these three statements dyanmically (Creates pl/sql block) and runs it.
As you have seen the three statements above, I am not able to write cursor properly for it. I was suggested by someone to write cursor, so i started. But as you can see my cursor won't satisfy all the "where not exists " and "where exists" conditions satifactorily.
I only tried insert in the cursor and compared it with the insert in the cursor. My procedure with cursor was slower than the the insert. But since i didn't tried the three things togather i.e. update, delete and insert, i guess theoritically write cursor will select data from the source table only once, which will improve performance. But i can't do that. The other way to solve this is writing to procedure, one having insert and delete in it (as the conditons are same in both) and the other having update statement in it. But this won't increase the performance to that extent i guess ?
Do you have any other solutions to write the 3 DML statements which I have written above.
Any help would be highly appreciated.
Thanks!

SQL Performance tuning with wildcard Like condition

Hi,
I have performance issue with SQL query.
When I am using "where emp_name like '%im%' " query is taking longer time than when I use "where emp_name like 'im%' " .
With former condition query takes 40 sec , with later it takes around 1.5 sec.
Both returns almost same no. of rows. We have function based index created on emp_name column.
With wildcard at both ends query goes for full table scan.
Can any one please suggest way so that query responce time can be reduced.?
I even tried using hints but still it is going for full table scan instead of using index.

>
Hi Mandark,
<I've rearranged your post>
When I am using "where emp_name like '%im%' " query is taking longer time than when I use "where emp_name like 'im%' " .
With wildcard at both ends query goes for full table scan.
I even tried using hints but still it is going for full table scan instead of using index.
With former condition query takes 40 sec , with later it takes around 1.5 sec.
Both returns almost same no. of rows. We have function based index created on emp_name column.You are never going to be able to speed things up with a double wild card - or even 1 wild card at the beginning
(unless you have some weird index reversing the string).
With the double wild-card, the system has to search through the string character by character to see
if there are any letter "i's" and then see if that letter is followed by an "m".
That's using your standard B-tree index (see below).
Can any one please suggest way so that query responce time can be reduced.?Yes, I think so - there is full-text indexing - see here:
http://www.dba-oracle.com/oracle_tips_like_sql_index.htm and
http://www.oracle-base.com/articles/9i/full-text-indexing-using-oracle-text-9i.php
AFAIK, it's an extra-cost option - but you can have fun finding out all that for yourself ;)
HTH,
Paul...

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 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

Performance tuning of BPEL processes in SOA Suite 11g

Hi,
We are working with a customer for performance tuning of SOA Suite 11g, one of the areas is to tune the BPEL processes. I am new to this and started out with stress testing Hello World process using SOAPUI tool. I would like help with the below topics -
1. How do I interpret the statistics collected during stress testing? Do we have any benchmark set that can indicate that the performance is ok.
2. Do we need to run stress tests for every BPEL process deployed?
2. Is there any performance tuning strategy documentation available? Or can anybody share his/her experiences to guide me?
Thanks in advance!
Sritama

1. How do I interpret the statistics collected during stress testing? Do we have any benchmark set that can indicate that the performance is ok.
You need
pay attention to:
java heap usage vs java heap capacity
java eden usage vs java eden capacity
JDBC pool initial connections vs JDBC pool capacity connections
if you are using linux: top
if you are using aix: topas
2. Do we need to run stress tests for every BPEL process deployed?
yes, you need test each BPEL. You can use "Jmeter" tool.
Download Jmeter from here: Apache JMeter - Apache JMeter&trade;
Other tools:
jstat
jstack
jps -v
Enterprise Manager
WebLogic Console
VisualVM
JRockit Mission Control
3. Is there any performance tuning strategy documentation available? Or can anybody share his/her experiences to guide me?
I recommend "Oracle SOA Suite 11g Performance Tuning Cookbook" http://www.amazon.com/Oracle-Suite-Performance-Tuning-Cookbook/dp/1849688842/ref=sr_1_1?ie=UTF8&qid=1378482031&sr=8-1&keywords=oracle+soa+suite+11g+performance+tuning+cookbook

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

Reg: Process Chain, query performance tuning steps

Hi All,
I come across a question like, There is a process chain of 20 processes.out of which 5 processes are completed at the 6th step error occured and it cannot be rectified. I should start the chain again from the 7th step.If i go to a prticular step i can do that particular step, How can i start the entair chain again from step 7.i know that i need to use a function module but i dont know the name of FM. Please somebody help me out.
Please let me know the steps involved in query performance tuning and aggregate tuning.
Thanks & Regards
Omkar.K

Hi,
Process Chain
Method 1 (when it fails in a step/request)
/people/siegfried.szameitat/blog/2006/02/26/restarting-processchains
How is it possible to restart a process chain at a failed step/request?
Sometimes, it doesn't help to just set a request to green status in order to run the process chain from that step on to the end.
You need to set the failed request/step to green in the database as well as you need to raise the event that will force the process chain to run to the end from the next request/step on.
Therefore you need to open the messages of a failed step by right clicking on it and selecting 'display messages'.
In the opened popup click on the tab 'Chain'.
In a parallel session goto transaction se16 for table rspcprocesslog and display the entries with the following selections:
1. copy the variant from the popup to the variante of table rspcprocesslog
2. copy the instance from the popup to the instance of table rspcprocesslog
3. copy the start date from the popup to the batchdate of table rspcprocesslog
Press F8 to display the entries of table rspcprocesslog.
Now open another session and goto transaction se37. Enter RSPC_PROCESS_FINISH as the name of the function module and run the fm in test mode.
Now copy the entries of table rspcprocesslog to the input parameters of the function module like described as follows:
1. rspcprocesslog-log_id -> i_logid
2. rspcprocesslog-type -> i_type
3. rspcprocesslog-variante -> i_variant
4. rspcprocesslog-instance -> i_instance
5. enter 'G' for parameter i_state (sets the status to green).
Now press F8 to run the fm.
Now the actual process will be set to green and the following process in the chain will be started and the chain can run to the end.
Of course you can also set the state of a specific step in the chain to any other possible value like 'R' = ended with errors, 'F' = finished, 'X' = cancelled ....
Check out the value help on field rspcprocesslog-state in transaction se16 for the possible values.
Query performance tuning
General tips
Using aggregates and compression.
Using less and complex cell definitions if possible.
1. Avoid using too many nav. attr
2. Avoid RKF and CKF
3. Many chars in row.
By using T-codes ST03 or ST03N
Go to transaction ST03 > switch to expert mode > from left side menu > and there in system load history and distribution for a particual day > check query execution time.
/people/andreas.vogel/blog/2007/04/08/statistical-records-part-4-how-to-read-st03n-datasets-from-db-in-nw2004
/people/andreas.vogel/blog/2007/03/16/how-to-read-st03n-datasets-from-db
Try table rsddstats to get the statistics
Using cache memoery will decrease the loading time of the report.
Run reporting agent at night and sending results to email.This will ensure use of OLAP cache. So later report execution will retrieve the result faster from the OLAP cache.
Also try
1. Use different parameters in ST03 to see the two important parameters aggregation ratio and records transferred to F/E to DB selected.
2. Use the program SAP_INFOCUBE_DESIGNS (Performance of BW infocubes) to see the aggregation ratio for the cube. If the cube does not appear in the list of this report, try to run RSRV checks on the cube and aggregates.
Go to SE38 > Run the program SAP_INFOCUBE_DESIGNS
It will shown dimension Vs Fact tables Size in percent.If you mean speed of queries on a cube as performance metric of cube,measure query runtime.
3. --- sign is the valuation of the aggregate. You can say -3 is the valuation of the aggregate design and usage. ++ means that its compression is good and access is also more (in effect, performance is good). If you check its compression ratio, it must be good. -- means the compression ratio is not so good and access is also not so good (performance is not so good).The more is the positives...more is useful the aggregate and more it satisfies the number of queries. The greater the number of minus signs, the worse the evaluation of the aggregate. The larger the number of plus signs, the better the evaluation of the aggregate.
if "-----" then it means it just an overhead. Aggregate can potentially be deleted and "+++++" means Aggregate is potentially very useful.
Refer.
http://help.sap.com/saphelp_nw70/helpdata/en/b8/23813b310c4a0ee10000000a114084/content.htm
http://help.sap.com/saphelp_nw70/helpdata/en/60/f0fb411e255f24e10000000a1550b0/frameset.htm
4. Run your query in RSRT and run the query in the debug mode. Select "Display Aggregates Found" and "Do not use cache" in the debug mode. This will tell you if it hit any aggregates while running. If it does not show any aggregates, you might want to redesign your aggregates for the query.
Also your query performance can depend upon criteria and since you have given selection only on one infoprovider...just check if you are selecting huge amount of data in the report
Check for the query read mode in RSRT.(whether its A,X or H)..advisable read mode is X.
5. In BI 7 statistics need to be activated for ST03 and BI admin cockpit to work.
By implementing BW Statistics Business Content - you need to install, feed data and through ready made reports which for analysis.
http://help.sap.com/saphelp_nw70/helpdata/en/26/4bc0417951d117e10000000a155106/frameset.htm
/people/vikash.agrawal/blog/2006/04/17/query-performance-150-is-aggregates-the-way-out-for-me
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/1955ba90-0201-0010-d3aa-8b2a4ef6bbb2
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/ce7fb368-0601-0010-64ba-fadc985a1f94
http://help.sap.com/saphelp_nw04/helpdata/en/c1/0dbf65e04311d286d6006008b32e84/frameset.htm
You can go to T-Code DB20 which gives you all the performance related information like
Partitions
Databases
Schemas
Buffer Pools
Tablespaces etc
use tool RSDDK_CHECK_AGGREGATE in se38 to check for the corrupt aggregates
If aggregates contain incorrect data, you must regenerate them.
Note 646402 - Programs for checking aggregates (as of BW 3.0B SP15)
Thanks,
JituK

Business Process Performance Tuning

Hi Pals,
I would like to request your help and inputs regarding tuning performance of Business process for my scenario.
I have created a synchronous Process with 3 message mapping transformation steps. ( inbetween Sync Receive and Sync Send steps). So its pretty simple process.
I am able to execute only 3500 processes per hour.
The SAP Netweaver Server m/c configuration is 2 dual core processors with 12 GB RAM.
Business process - Without buffering with multiple queues (content specific).
IE Logging - No sync logging, logging level - 0 ( so logging turned off )
I have tried out all the configurations mentioned in below weblogs, but with very less improvement in my case.
Performance Tuning Checks in SAP Exchange Infrastructure(XI): Part-III
Performance Tuning Checks in SAP Exchange Infrastructure(XI): Part-II
Performance Tuning Checks in SAP Exchange Infrastructure
I think something else is choking the execution, as the CPU or memory usage is not more than 10-20%.
Please pour in your inputs.
Thank you!
Best Regards,
Saravanan N

Thank you very much Bhavesh!
In my BPM, all the steps are set for "No New Transaction". So as to avoid any performance issue. But there is no improvement.
Even I have deleted all the work-items from Trxn: SWWL before the test.
From ST03N, for each process instance executed, four function modules takes the maximum time.
Function Module--No. of Calls--
Execution Time/RFC Call
TRFC_QIN_DEST_SHIP-- 1--
995 milliseconds
TRFC_QIN_ACTIVATE--1--
1077 milliseconds
ARFC_DEST_SHIP--2--
280 milliseconds
ARFC_RUN_NOWAIT--2--
402 milliseconds
Best Regards,
Saravanan N

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

HOW TO: Post a SQL statement tuning request - template posting

This post is not a question, but similar to Rob van Wijk's "When your query takes too long ..." post should help to improve the quality of the requests for SQL statement tuning here on OTN.
On the OTN forum very often tuning requests about single SQL statements are posted, but the information provided is rather limited, and therefore it's not that simple to provide a meaningful advice. Instead of writing the same requests for additional information over and over again I thought I put together a post that describes how a "useful" post for such a request should look like and what information it should cover.
I've also prepared very detailed step-by-step instructions how to obtain that information on my blog, which can be used to easily gather the required information. It also covers again the details how to post the information properly here, in particular how to use the \ tag to preserve formatting and get a fixed font output:
http://oracle-randolf.blogspot.com/2009/02/basic-sql-statement-performance.html
So again: This post here describes how a "useful" post should look like and what information it ideally covers. The blog post explains in detail how to obtain that information.
In the future, rather than requesting the same additional information and explaining how to obtain it, I'll simply refer to this HOW TO post and the corresponding blog post which describes in detail how to get that information.
*Very important:*
Use the \ tag to enclose any output that should have its formatting preserved as shown below.
So if you want to use fixed font formatting that preserves the spaces etc., do the following:
\   This preserves formatting
\And it will look like this:
   This preserves formatting
   . . .Your post should cover the following information:
1. The SQL and a short description of its purpose
2. The version of your database with 4-digits (e.g. 10.2.0.4)
3. Optimizer related parameters
4. The TIMING and AUTOTRACE output
5. The EXPLAIN PLAN output
6. The TKPROF output snippet that corresponds to your statement
7. If you're on 10g or later, the DBMS_XPLAN.DISPLAY_CURSOR output
The above mentioned blog post describes in detail how to obtain that information.
Your post should have a meaningful subject, e.g. "SQL statement tuning request", and the message body should look similar to the following:
*-- Start of template body --*
The following SQL statement has been identified to perform poorly. It currently takes up to 10 seconds to execute, but it's supposed to take a second at most.
This is the statement:
select
from
         t_demo
where
         type = 'VIEW'
order by
         id;It should return data from a table in a specific order.
The version of the database is 11.1.0.7.
These are the parameters relevant to the optimizer:
SQL>
SQL> show parameter optimizer
NAME                                 TYPE        VALUE
optimizer_capture_sql_plan_baselines boolean     FALSE
optimizer_dynamic_sampling           integer     2
optimizer_features_enable            string      11.1.0.7
optimizer_index_caching              integer     0
optimizer_index_cost_adj             integer     100
optimizer_mode                       string      ALL_ROWS
optimizer_secure_view_merging        boolean     TRUE
optimizer_use_invisible_indexes      boolean     FALSE
optimizer_use_pending_statistics     boolean     FALSE
optimizer_use_sql_plan_baselines     boolean     TRUE
SQL>
SQL> show parameter db_file_multi
NAME                                 TYPE        VALUE
db_file_multiblock_read_count        integer     8
SQL>
SQL> show parameter db_block_size
NAME                                 TYPE        VALUE
db_block_size                        integer     8192
SQL>
SQL> show parameter cursor_sharing
NAME                                 TYPE        VALUE
cursor_sharing                       string      EXACT
SQL>
SQL> column sname format a20
SQL> column pname format a20
SQL> column pval2 format a20
SQL>
SQL> select
2            sname
3          , pname
4          , pval1
5          , pval2
6 from
7          sys.aux_stats$;
SNAME                PNAME                     PVAL1 PVAL2
SYSSTATS_INFO        STATUS                          COMPLETED
SYSSTATS_INFO        DSTART                          01-30-2009 16:25
SYSSTATS_INFO        DSTOP                           01-30-2009 16:25
SYSSTATS_INFO        FLAGS                         0
SYSSTATS_MAIN        CPUSPEEDNW              494,397
SYSSTATS_MAIN        IOSEEKTIM                    10
SYSSTATS_MAIN        IOTFRSPEED                 4096
SYSSTATS_MAIN        SREADTIM
SYSSTATS_MAIN        MREADTIM
SYSSTATS_MAIN        CPUSPEED
SYSSTATS_MAIN        MBRC
SYSSTATS_MAIN        MAXTHR
SYSSTATS_MAIN        SLAVETHR
13 rows selected.Here is the output of EXPLAIN PLAN:
SQL> explain plan for
2 -- put your statement here
3 select
4            *
5 from
6            t_demo
7 where
8            type = 'VIEW'
9 order by
10            id;
Explained.
Elapsed: 00:00:00.01
SQL>
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
Plan hash value: 1390505571
| Id | Operation                   | Name     | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |          |     1 |    60 |     0   (0)| 00:00:01 |
|   1 | TABLE ACCESS BY INDEX ROWID| T_DEMO   |     1 |    60 |     0   (0)| 00:00:01 |
|* 2 |   INDEX RANGE SCAN          | IDX_DEMO |     1 |       |     0   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - access("TYPE"='VIEW')
14 rows selected.Here is the output of SQL*Plus AUTOTRACE including the TIMING information:
SQL> rem Set the ARRAYSIZE according to your application
SQL> set autotrace traceonly arraysize 100
SQL> select
2            *
3 from
4            t_demo
5 where
6            type = 'VIEW'
7 order by
8            id;
149938 rows selected.
Elapsed: 00:00:02.21
Execution Plan
Plan hash value: 1390505571
| Id | Operation                   | Name     | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |          |     1 |    60 |     0   (0)| 00:00:01 |
|   1 | TABLE ACCESS BY INDEX ROWID| T_DEMO   |     1 |    60 |     0   (0)| 00:00:01 |
|* 2 |   INDEX RANGE SCAN          | IDX_DEMO |     1 |       |     0   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - access("TYPE"='VIEW')
Statistics
          0 recursive calls
          0 db block gets
     149101 consistent gets
        800 physical reads
        196 redo size
    1077830 bytes sent via SQL*Net to client
      16905 bytes received via SQL*Net from client
       1501 SQL*Net roundtrips to/from client
          0 sorts (memory)
          0 sorts (disk)
     149938 rows processed
SQL>
SQL> disconnect
Disconnected from Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing optionsThe TKPROF output for this statement looks like the following:
TKPROF: Release 11.1.0.7.0 - Production on Mo Feb 23 10:23:08 2009
Copyright (c) 1982, 2007, Oracle. All rights reserved.
Trace file: orcl11_ora_3376_mytrace1.trc
Sort options: default
count    = number of times OCI procedure was executed
cpu      = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk     = number of physical reads of buffers from disk
query    = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows     = number of rows processed by the fetch or execute call
select
from
         t_demo
where
         type = 'VIEW'
order by
         id
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.00       0.00          0          0          0           0
Execute      1      0.00       0.00          0          0          0           0
Fetch     1501      0.53       1.36        800     149101          0      149938
total     1503      0.53       1.36        800     149101          0      149938
Misses in library cache during parse: 0
Optimizer mode: ALL_ROWS
Parsing user id: 88
Rows     Row Source Operation
149938 TABLE ACCESS BY INDEX ROWID T_DEMO (cr=149101 pr=800 pw=0 time=60042 us cost=0 size=60 card=1)
149938   INDEX RANGE SCAN IDX_DEMO (cr=1881 pr=1 pw=0 time=0 us cost=0 size=0 card=1)(object id 74895)
Elapsed times include waiting on following events:
Event waited on                             Times   Max. Wait Total Waited
----------------------------------------   Waited ---------- ------------
SQL*Net message to client                    1501        0.00          0.00
db file sequential read                       800        0.05          0.80
SQL*Net message from client                  1501        0.00          0.69
********************************************************************************The DBMS_XPLAN.DISPLAY_CURSOR output:
SQL> -- put your statement here
SQL> -- use the GATHER_PLAN_STATISTICS hint
SQL> -- if you're not using STATISTICS_LEVEL = ALL
SQL> select /*+ gather_plan_statistics */
2 *
3 from
4 t_demo
5 where
6 type = 'VIEW'
7 order by
8 id;
149938 rows selected.
Elapsed: 00:00:02.21
SQL>
SQL> select * from table(dbms_xplan.display_cursor(null, null, 'ALLSTATS LAST'));
PLAN_TABLE_OUTPUT
SQL_ID d4k5acu783vu8, child number 0
select   /*+ gather_plan_statistics */          * from          t_demo
where          type = 'VIEW' order by          id
Plan hash value: 1390505571
| Id | Operation                   | Name     | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads |
|   0 | SELECT STATEMENT            |          |      1 |        |    149K|00:00:00.02 |     149K|   1183 |
|   1 | TABLE ACCESS BY INDEX ROWID| T_DEMO   |      1 |      1 |    149K|00:00:00.02 |     149K|   1183 |
|* 2 |   INDEX RANGE SCAN          | IDX_DEMO |      1 |      1 |    149K|00:00:00.02 |    1880 |    383 |
Predicate Information (identified by operation id):
   2 - access("TYPE"='VIEW')
20 rows selected.I'm looking forward for suggestions how to improve the performance of this statement.
*-- End of template body --*
I'm sure that if you follow these instructions and obtain the information described, post them using a proper formatting (don't forget about the \ tag) you'll receive meaningful advice very soon.
So, just to make sure you didn't miss this point:Use proper formatting!
If you think I missed something important in this sample post let me know so that I can improve it.
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
SQLTools++ for Oracle (Open source Oracle GUI for Windows):
http://www.sqltools-plusplus.org:7676/
http://sourceforge.net/projects/sqlt-pp/

Alex Nuijten wrote:
...you missed the proper formatting of the Autotrace section ;-)Alex,
can't reproduce, does it still look unformatted? Or are you simply kidding? :-)
Randolf
PS: Just noticed that it actually sometimes doesn't show the proper formatting although the code tags are there. Changing to the \ tag helped in this case, but it seems to be odd.
Edited by: Randolf Geist on Feb 23, 2009 11:28 AM
Odd behaviour of forum software

Performance Tuning in IR

Hello All,
We have created some reports using Interactive Reporting Studio. The volume of data in that Oracle database are huge and in some tables of the relational database are having above 3-4 crores rows individually. We have created the .oce connection file using the 'Oracle Net' option. Oracle client ver is 10g. We earlier created pivot, chart and report in those .bqy files but had to delete those where-ever possible to decrease the processing time for getting those report generated.
But deleting those from the file and retaining just the result section (the bare minimum part of the file) even not yet helped us out solving the performance issue fully. Still now, in some reports, system gives error message 'Out of Memory' at the time of processing those reports. The memory of the client PCs,wherefrom the reports are being generated are 1 - 1.5 GB. For some reports, even it takes 1-2 hours for saving the results after process. In some cases, the PCs gets hanged at the time of processing. When we extract the query of those reports in sql and run them in TOAD/SQL PLUS, they take not so much time like IR.
Would you please help us out in the aforesaid issue ASAP? Please share your views/tips/suggestions etc in respect of performance tuning for IR. All reply would be highly appreciated.
Regards,
Raj

SQL + & Toad are tools that send SQL and spool results; IR is a tool that sends a request to the database to run SQL and then fiddles with the results before the user is even told data has been received. You need to minimize the time spent by IR manipulating results into objects the user isn't even asking for.
When a request is made to the database, Hyperion will wait until all of the results have been received. Once ALL of the results have been received, then IR will make multiple passes to apply sorts, filters and computed items existing in the results section. For some unknown reason, those three steps are performed more inefficiently then they would be performed in a table section. Only after all of the computed items have been calculated, all filters applied and all sorts sorted, then IR will start to calculate any reports, charts and pivots. After all that is done, the report stops processing and the data has been "returned"
To increase performance, you need to fine tune your IR Services and your BQY docs. Replicate your DAS on your server - it can only transfer 2g before it dies, restarts and your requested document hangs. You can replicated the DAS multiple times and should do so to make sure there are enough resources available for any concurrent users to make necessary requests and have data delivered to them.
To tune your bqy documents...
1) Your Results section MUST be free of any sorts, filters, or computed items. Create a staging table and put any sorts or local filters there. Move as many of your computed items to your database request line and ask the database to make the calculation (either directly or through stored procedures) so you are not at the mercy of the client machine. Any computed items that cannot be moved to the request line, need to be put on your new staging table.
2) Ask the users to choose filters. Programmatically build dynamic filters based on what the user is looking for. The goal is to cast a net only as big as the user needs so you are not bringing back unnecessary data. Otherwise, you will bring your server and client machines to a grinding halt.
3) Halt any report pagination. Built your reports from their own tables and put a dummy filter on the table that forces 0 rows in the table until the report is invoked. Hyperion will paginate every report BEFORE it even tells the user it has results so this will prevent the user from waiting an hour while 1000s of pages are paginated across multiple reports
4) Halt any object rendering until request. Same as above - create a system programmically for the user to tell the bqy what they want so they are not waiting forever for a pivot and 2 reports to compile and paginate when they want just a chart.
5) Saved compressed documents
6) Unless this document can be run as a job, there should be NO results stored with the document but if you do save results with the document, store the calculations too so you at least don't have to wait for them to pass again.
7) Remove all duplicate images and keep the image file size small.
Hope this helps!
PS: I forgot to mention - aside from results sections, in documents where the results are NOT saved, additional table sections take up very, very, very small bits of file size and, as long as there are not excessively larger images the same is true for Reports, Pivots and Charts. Additionally, the impact of file size only matters when the user is requesting the document. The file size is never an issue when the user is processing the report because it has already been delivered to them and cached (in workspace and in the web client)
Edited by: user10899957 on Feb 10, 2009 6:07 AM

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

How can I improve below SQL performance.

Hi,
How can I improve below SQL performance. This SQL consumes CPU and occures wait events. It is running every 10 seconds. When I look at the session information from Enterprise Manager I can see that "Histogram for Wait Event: PX Deq Credit: send blkd"
I created some indexes. I heard that the indexes are not used when there is a NULL but when I checked the xecution plan It uses index.
SELECT i.ID
FROM EXPRESS.invoices i
WHERE i.nbr IS NOT NULL
AND i.EXTRACT_BATCH IS NULL
AND i.SUB_TYPE='COD'
Explain Plan from Toad
SELECT STATEMENT CHOOSECost: 77 Bytes: 6,98 Cardinality: 349
     4 PX COORDINATOR
          3 PX SEND QC (RANDOM) SYS.:TQ10000 Cost: 77 Bytes: 6,98 Cardinality: 349
               2 PX BLOCK ITERATOR Cost: 77 Bytes: 6,98 Cardinality: 349
                    1 INDEX FAST FULL SCAN INDEX EXPRESS.INVC_TRANS_INDX Cost: 77 Bytes: 6,98 Cardinality: 349
Execution Plan from Sqlplus
| Id | Operation | Name | Rows | Bytes | Cost | TQ |IN-OUT| PQ Distrib |
| 0 | SELECT STATEMENT | | 349 | 6980 | 77 | | | |
| 1 | PX COORDINATOR | | | | | | | |
| 2 | PX SEND QC (RANDOM) | :TQ10000 | 349 | 6980 | 77 | Q1,00 | P->S | QC (RAND) |
| 3 | PX BLOCK ITERATOR | | 349 | 6980 | 77 | Q1,00 | PCWC | |
|* 4 | INDEX FAST FULL SCAN| INVC_TRANS_INDX | 349 | 6980 | 77 | Q1,00 | PCWP | |
Predicate Information (identified by operation id):
4 - filter("I"."NBR" IS NOT NULL AND "I"."EXTRACT_BATCH" IS NULL AND "I"."SUB_TYPE"='COD')
Note
- 'PLAN_TABLE' is old version
- cpu costing is off (consider enabling it)
Statistics
141 recursive calls
0 db block gets
5568 consistent gets
0 physical reads
0 redo size
319 bytes sent via SQL*Net to client
458 bytes received via SQL*Net from client
1 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
0 rows processed
Instance Efficiency Percentages (Target 100%)
Buffer Nowait %: 100.00
Redo NoWait %: 100.00
Buffer Hit %: 99.70
In-memory Sort %: 100.00
Library Hit %: 99.81
Soft Parse %: 99.77
Execute to Parse %: 63.56
Latch Hit %: 90.07
Parse CPU to Parse Elapsd %: 0.81
% Non-Parse CPU: 98.88
Top 5 Timed Events
Event     Waits     Time(s)     Avg Wait(ms)     % Total Call Time     Wait Class
latch: library cache     12,626     16,757     1,327     62.6     Concurrency
CPU time          5,712          21.Mar
latch: session allocation     1,848,987     1,99     1     07.Nis     Other
PX Deq Credit: send blkd     1,242,265     981     1     03.Tem     Other
PX qref latch     1,405,819     726     1     02.Tem     Other
The database version is 10.2.0.1 but we haven't installed the patch 10.2.0.5. yet.
I am waiting your comments.
Thanks in advance

Welcome to the forum.
I created some indexes. I heard that the indexes are not used when there is a NULL but when I checked the xecution plan It uses index. What columns are indexed?
And what do:
select i.sub_type
,      count(*)
from   express.invoices i
where i.nbr is not null
and    i.extract_batch is null
group by i.sub_type; and
select i.sub_type
,      count(*)
from   express.invoices i
group by i.sub_type; return?
Also, try use the {noformat}{noformat} tag when posting examples/execution plans etc.
See: HOW TO: Post a SQL statement tuning request - template posting for more tuning instructions.
It'll make a big difference:
SELECT i.ID
FROM EXPRESS.invoices i
WHERE i.nbr IS NOT NULL
AND i.EXTRACT_BATCH IS NULL
AND i.SUB_TYPE='COD'
Explain Plan from Toad
SELECT STATEMENT CHOOSECost: 77 Bytes: 6,98 Cardinality: 349
     4 PX COORDINATOR
          3 PX SEND QC (RANDOM) SYS.:TQ10000 Cost: 77 Bytes: 6,98 Cardinality: 349
               2 PX BLOCK ITERATOR Cost: 77 Bytes: 6,98 Cardinality: 349
                    1 INDEX FAST FULL SCAN INDEX EXPRESS.INVC_TRANS_INDX Cost: 77 Bytes: 6,98 Cardinality: 349
Execution Plan from Sqlplus
| Id | Operation | Name | Rows | Bytes | Cost | TQ |IN-OUT| PQ Distrib |
| 0 | SELECT STATEMENT | | 349 | 6980 | 77 | | | |
| 1 | PX COORDINATOR | | | | | | | |
| 2 | PX SEND QC (RANDOM) | :TQ10000 | 349 | 6980 | 77 | Q1,00 | P->S | QC (RAND) |
| 3 | PX BLOCK ITERATOR | | 349 | 6980 | 77 | Q1,00 | PCWC | |
|* 4 | INDEX FAST FULL SCAN| INVC_TRANS_INDX | 349 | 6980 | 77 | Q1,00 | PCWP | |
Predicate Information (identified by operation id):
4 - filter("I"."NBR" IS NOT NULL AND "I"."EXTRACT_BATCH" IS NULL AND "I"."SUB_TYPE"='COD')
Note
- 'PLAN_TABLE' is old version
- cpu costing is off (consider enabling it)
Statistics
141 recursive calls
0 db block gets
5568 consistent gets
0 physical reads
0 redo size
319 bytes sent via SQL*Net to client
458 bytes received via SQL*Net from client
1 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
0 rows processed
Instance Efficiency Percentages (Target 100%)
Buffer Nowait %: 100.00
Redo NoWait %: 100.00
Buffer Hit %: 99.70
In-memory Sort %: 100.00
Library Hit %: 99.81
Soft Parse %: 99.77
Execute to Parse %: 63.56
Latch Hit %: 90.07
Parse CPU to Parse Elapsd %: 0.81
% Non-Parse CPU: 98.88
Top 5 Timed Events
Event     Waits     Time(s)     Avg Wait(ms)     % Total Call Time     Wait Class
latch: library cache     12,626     16,757     1,327     62.6     Concurrency
CPU time          5,712          21.Mar
latch: session allocation     1,848,987     1,99     1     07.Nis     Other
PX Deq Credit: send blkd     1,242,265     981     1     03.Tem     Other
PX qref latch     1,405,819     726     1     02.Tem     Other

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