Performance problem using on change

Hi abapers,
i am using ON CHANGE OF...END ON,,, AT END OF statements in My program.
will this statements effect on performance.
if so , is there any alternative?
please help .

Hi Ramesh,
I don't know what are the performance implications with this statement, but SAP says that it is an Obsolete control structure.
You cannot use them in class contexts.(This statement is forbidden in classes).
More over, SAP Hep also says that,
<b>"For each time the statement ON CHANGE OF is executed, the content of all the specified data objects is saved as an auxiliary variable internally in the global system. The auxiliary variable is linked to this statement and cannot be accessed in the program. The auxiliary variables and their contents are retained longer than the lifetime of procedures. An auxiliary variable of this type can only be initialized if its statement ON CHANGE OF is executed while the associated data object is initial. "</b>
Regards,
Ravi Kanth

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Performance problem using OBJECT tag

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Mike wrote:
Joe,
This was actually my next step. I replaced the BEA driver with
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Joe
>
>
Mike
The next test you should do, to isolate the issue, is to try another
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it would be
interesting. However, it would still not isolate the problem, because
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Joe Weinstein at BEA
PS: I can only tell you that our driver has not changed in it's semantic
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I had done this from the very beginning, but I was still getting very bad performance under
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this will solve the problem.
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Tamilselvan Ramasamy wrote:
You have to use Oracle's Oracle 9i thin driver .
put this driver infront of the classpath i.e before weblogic_sp.jar and
weblogic.jar
/selvan
"Sree Bodapati" <[email protected]> wrote in message
news:[email protected]..
The BEA driver is available in WLS6.1SP2 which is GA.
hth
sree
"Samuel Kounev" <[email protected]> wrote in message
news:[email protected]..
Hello everyone,
Has anyone been experimenting with the thin driver for Oracle 9i under
WLS6.1. I got it running, but
I get extremely bad performance when having multiple concurrent accesses.
It
works more or less in
single user mode. Also it seems not to support XA transactions?
When could we expect the driver from BEA to be out?
Thanks in advance!
Samuel Kounev
TU-Darmstadt, Germany

Many-to-many Performance Problem (Using FAQ Template)

Having read "HOW TO: Post a SQL statement tuning request - template posting" I have gathered:
I have included some background information at the bottom of the post
The following SQL statement has been identified as performing poorly. It takes ~160 seconds to execute, but similar (shown below first statement) SQL statements executes in ~1 second.
SQL taking 160 seconds:
SELECT
a.*
FROM
table_a a
INNER JOIN table_a_b ab ON a.id = ab.media_fk
WHERE
ab.channel_fk IN (7, 1);SQL taking ~1 second or less
ab.channel_fk IN (7);Or even:
ab.channel_fk IN (6, 9, 170, 89);The purpose of the SQL is to return rows from table_a that are associated with table_b (not in SQL) through the junction table table_a_b.
The version of the database is 10.2.0.4.0
These are the parameters relevant to the optimizer:
show parameter optimizer;
NAME                                               TYPE        VALUE
optimizer_dynamic_sampling                         integer     2
optimizer_features_enable                          string      10.2.0.4
optimizer_index_caching                            integer     0
optimizer_index_cost_adj                           integer     100
optimizer_mode                                     string      ALL_ROWS
optimizer_secure_view_merging                      boolean     TRUE
show parameter db_file_multi;
NAME                                               TYPE        VALUE
db_file_multiblock_read_count                      integer     16
show parameter db_block_size;
NAME                                               TYPE        VALUE
db_file_multiblock_read_count                      integer     16
select sname, pname, pval1, pval2 from sys.aux_stats$;
SNAME                          PNAME                          PVAL1                  PVAL2
SYSSTATS_INFO                  STATUS                                                COMPLETED
SYSSTATS_INFO                  DSTART                                                07-18-2006 23:19
SYSSTATS_INFO                  DSTOP                                                 07-25-2006 23:19
SYSSTATS_INFO                  FLAGS                          0
SYSSTATS_MAIN                  SREADTIM                       5.918
SYSSTATS_MAIN                  MREADTIM                       7.889
SYSSTATS_MAIN                  CPUSPEED                       1383
SYSSTATS_MAIN                  MBRC                           8
SYSSTATS_MAIN                  MAXTHR                         1457152
SYSSTATS_MAIN                  SLAVETHR                       -1Here is the output of EXPLAIN PLAN:
PLAN_TABLE_OUTPUT
Plan hash value: 3781163428
| Id | Operation             | Name               | Rows | Bytes |TempSpc| Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT      |                    | 1352K|   771M|       | 60042   (3)| 00:05:56 |
|* 1 | HASH JOIN            |                    | 1352K|   771M|    27M| 60042   (3)| 00:05:56 |
|* 2 |   INDEX FAST FULL SCAN| SYS_IOT_TOP_316310 | 1352K|    11M|       | 1816   (4)| 00:00:11 |
|   3 |   TABLE ACCESS FULL   | TABLE_A            | 2190K| 1230M|       | 32357   (4)| 00:03:12 |
Predicate Information (identified by operation id):
   1 - access(""AB"".""MEDIA_FK""=""A"".""ID"")
   2 - filter(""AB"".""CHANNEL_FK""=1 OR ""AB"".""CHANNEL_FK""=7)
Note
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ab.channel_fk IN (6, 9, 170, 89);which executes in ~1 second is:
PLAN_TABLE_OUTPUT
Plan hash value: 794334170
| Id | Operation          | Name      | Rows | Bytes |TempSpc| Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT   |           |   143K|    81M|       | 58982   (3)| 00:05:50 |
|* 1 | HASH JOIN         |           |   143K|    81M| 2952K| 58982   (3)| 00:05:50 |
|   2 |   INLIST ITERATOR |           |       |       |       |            |          |
|* 3 |    INDEX RANGE SCAN| C_M_INDEX |   143K| 1262K|       | 1264   (1)| 00:00:08 |
|   4 |   TABLE ACCESS FULL| TABLE_A   | 2190K| 1230M|       | 32357   (4)| 00:03:12 |
Predicate Information (identified by operation id):
   1 - access(""AB"".""MEDIA_FK""=""A"".""ID"")
   3 - access(""AB"".""CHANNEL_FK""=6 OR ""AB"".""CHANNEL_FK""=9 OR
              ""AB"".""CHANNEL_FK""=89 OR ""AB"".""CHANNEL_FK""=170)
Note
   - 'PLAN_TABLE' is old versionHere is the output of SQL*Plus AUTOTRACE including the TIMING information:
SQL> set autotrace traceonly arraysize 100;
SQL> SELECT
2 a.*
3 FROM
4 table_a a
5 INNER JOIN table_a_b ab ON a.id = ab.media_fk
6 WHERE
7 ab.channel_fk IN (7, 1);
1336148 rows selected.
Execution Plan
Plan hash value: 3781163428
| Id | Operation             | Name               | Rows | Bytes |TempSpc| Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT      |                    | 1352K|   771M|       | 60042   (3)| 00:05:56 |
|* 1 | HASH JOIN            |                    | 1352K|   771M|    27M| 60042   (3)| 00:05:56 |
|* 2 |   INDEX FAST FULL SCAN| SYS_IOT_TOP_316310 | 1352K|    11M|       | 1816   (4)| 00:00:11 |
|   3 |   TABLE ACCESS FULL   | TABLE_A            | 2190K| 1230M|       | 32357   (4)| 00:03:12 |
Predicate Information (identified by operation id):
   1 - access("AB"."MEDIA_FK"="A"."ID")
   2 - filter("AB"."CHANNEL_FK"=1 OR "AB"."CHANNEL_FK"=7)
Note
   - 'PLAN_TABLE' is old version
Statistics
      10586 recursive calls
          0 db block gets
     200457 consistent gets
     408343 physical reads
          0 redo size
498740848 bytes sent via SQL*Net to client
     147371 bytes received via SQL*Net from client
      13363 SQL*Net roundtrips to/from client
         49 sorts (memory)
          0 sorts (disk)
    1336148 rows processedThe TKPROF output for this statement looks like the following:
TKPROF: Release 10.2.0.4.0 - Production on Mon Oct 1 12:23:21 2012
Copyright (c) 1982, 2007, Oracle. All rights reserved.
Trace file: ..._ora_4896.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
ALTER SYSTEM SET TIMED_STATISTICS = TRUE
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.00       0.00          0          0          0           0
Execute      1      0.00       0.03          0          0          0           0
Fetch        0      0.00       0.00          0          0          0           0
total        2      0.00       0.03          0          0          0           0
Misses in library cache during parse: 0
Parsing user id: 21
SELECT
a.*
FROM
table_a a
INNER JOIN table_a_b ab ON a.id = ab.media_fk
WHERE
ab.channel_fk IN (7, 1)
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.01       0.00          0          0          0           0
Execute      1      0.00       0.00          0          0          0           0
Fetch        2     27.23     163.57     179906     198394          0          16
total        4     27.25     163.58     179906     198394          0          16
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 21
OVERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS
call     count       cpu    elapsed       disk      query    current        rows
Parse        2      0.01       0.00          0          0          0           0
Execute      2      0.00       0.03          0          0          0           0
Fetch        2     27.23     163.57     179906     198394          0          16
total        6     27.25     163.62     179906     198394          0          16
Misses in library cache during parse: 1
OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS
call     count       cpu    elapsed       disk      query    current        rows
Parse        0      0.00       0.00          0          0          0           0
Execute      0      0.00       0.00          0          0          0           0
Fetch        0      0.00       0.00          0          0          0           0
total        0      0.00       0.00          0          0          0           0
Misses in library cache during parse: 0
    2 user SQL statements in session.
    0 internal SQL statements in session.
    2 SQL statements in session.
Trace file: ..._ora_4896.trc
Trace file compatibility: 10.01.00
Sort options: default
       1 session in tracefile.
       2 user SQL statements in trace file.
       0 internal SQL statements in trace file.
       2 SQL statements in trace file.
       2 unique SQL statements in trace file.
      46 lines in trace file.
     187 elapsed seconds in trace file.The DBMS_XPLAN.DISPLAY_CURSOR output:
select * from table(dbms_xplan.display_cursor('474frsqbc1n4d', null, 'ALLSTATS LAST'));
PLAN_TABLE_OUTPUT
SQL_ID 474frsqbc1n4d, child number 0
SELECT /*+ gather_plan_statistics */ c.* FROM table_a c INNER JOIN table_a_b ab ON c.id = ab.media_fk WHERE ab.channel_fk IN (7, 1)
Plan hash value: 3781163428
| Id | Operation             | Name               | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads | Writes | OMem | 1Mem | Used-Mem |
|* 1 | HASH JOIN            |                    |      1 |   1352K|   1050 |00:00:40.93 |     198K|    182K|    209K|    29M| 5266K| 3320K (1)|
|* 2 |   INDEX FAST FULL SCAN| SYS_IOT_TOP_316310 |      1 |   1352K|   1336K|00:00:01.34 |   10874 |      0 |      0 |       |       |          |
|   3 |   TABLE ACCESS FULL   | TABLE_A            |      1 |   2190K|   2267K|00:02:45.56 |     187K|    182K|      0 |       |       |          |
Predicate Information (identified by operation id):
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   2 - filter((""AB"".""CHANNEL_FK""=1 OR ""AB"".""CHANNEL_FK""=7))Thank you for reading I'm looking forward for suggestions how to improve the performance of this statement.
h3. Backgroud
Many years ago my company made the decision to store many-to-many relationships in our database using pipe delimited fields. An example field value:
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WHERE
INSTR(pipedcolumn, '|ABC|') > 0
OR INSTR(pipedcolumn, '|XYZ|' > 0
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TABLE_A_B DDL:
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        channel_fk NUMBER,
        PRIMARY KEY (media_fk, channel_fk),
        FOREIGN KEY (media_fk) REFERENCES TABLE_A (ID),
        FOREIGN KEY (channel_fk) REFERENCES TABLE_B (ID)
    ) ORGANIZATION INDEX COMPRESS;
    CREATE INDEX C_M_INDEX ON TABLE_A_B (channel_fk, media_fk) COMPRESS;And parsing out a pipe delimited field, populated this new table.
I then compared the performance of the following SQL:
SELECT
a.*
FROM
table_a a
INNER JOIN table_a_b ab ON a.id = ab.media_fk
WHERE
ab.channel_fk IN (x, y, n); -- Can be Many Minutes
--vs.
SELECT
a.*
FROM
table_a a
WHERE
INSTR(OWNERS,'|x|')    >0
OR INSTR(OWNERS,'|y|')    >0
OR INSTR(OWNERS,'|n|')    >0; -- About 1 second seemingly regardlessWhen x, y, n are values that occur less frequently in TABLE_A_B.CHANNEL_FK the performance is comparable. However once the frequency of x, y, n increases the performance suffers. Here is a summary of the CHANNEL_FK data in TABLE_A_B:
--SQL For Summary Data
SELECT channel_fk, count(channel_fk) FROM table_a_b GROUP BY channel_fk ORDER BY COUNT(channel_fk) DESC;
CHANNEL_FK             COUNT(CHANNEL_FK)
7                      780741
1                      555407
2                      422493
3                      189493
169                    144663
9                      79457
6                      53051
171                    28401
170                    19857
49                     12603
...I've noticed that once I use any combination of values which occur more than about 800,000 times (i.e. IN (7, 1) = 780741 + 555407 = 1336148) then I get performance issues.
I'm finding it very difficult to accept that the old pipe delimited fields are a better solution (ignoring everything other than this search criteria!).
Thank you for reading this far. I truly look forward to suggestions on how to improve the performance of this statement.
Edited by: user1950227 on Oct 1, 2012 12:06 PM
Renamed link table in DDL.

Possibly not, I followed the instructions as best as I could but may have missed things.
h5. 1. DDL for all tables and indexes?
h6. - TABLE_A_B is described above and has a total of 2,304,642 rows. TABLE_A and TABLE_B are described below.
h5. 2. row counts for all tables?
h6. - See below
h5. 3. row counts for the predicates involved?
h6. - Not sure what your asking for, I have a summary of data in TABLE_A_B above. Could you clarify please?
h5. 4. Method and command used to collect stats on the tables and indexes?
h6. - For the stats I collected above I have included the command used to collect the data. If you are asking for further data I am happy to provide it but need more information. Thanks.
TABLE_A has 2,267,980 rows. The DLL that follows has been abbriviated, only the column involved is described.
-- DDL for Table TABLE_A
CREATE TABLE "NS"."TABLE_A"
   (     "ID" NUMBER
     --Lots more columns
   ) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 106496 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "CUSTOMNAMESPACE" ;
-- DDL for Index ID_PK
CREATE UNIQUE INDEX "NS"."MI_PK" ON "NS"."TABLE_A" ("ID")
PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 16384 NEXT 29458432 MINEXTENTS 1 MAXEXTENTS 505
PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "SYSTEM" ;
-- Constraints for Table TABLE_A
ALTER TABLE "NS"."TABLE_A" ADD CONSTRAINT "MI_PK" PRIMARY KEY ("ID")
USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 16384 NEXT 29458432 MINEXTENTS 1 MAXEXTENTS 505
PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "SYSTEM" ENABLE;
ALTER TABLE "NS"."TABLE_A" MODIFY ("ID" NOT NULL ENABLE);TABLE_B has 22 rows. The DLL that follows has been abbriviated, only the column involved is described.
-- DDL for Table TABLE_B
CREATE TABLE "NS"."TABLE_B"
     "ID" NUMBER
--Lots more columns
   ) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 106496 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "CUSTOMNAMESPACE" ;
-- DDL for Index CID_PK
CREATE UNIQUE INDEX "NS"."CID_PK" ON "NS"."TABLE_B" ("ID")
PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 16384 NEXT 16384 MINEXTENTS 1 MAXEXTENTS 505
PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "SYSTEM" ;
-- Constraints for Table TABLE_B
ALTER TABLE "NS"."TABLE_B" ADD CONSTRAINT "CID_PK" PRIMARY KEY ("ID")
USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 16384 NEXT 16384 MINEXTENTS 1 MAXEXTENTS 505
PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "SYSTEM" ENABLE;
ALTER TABLE "NS"."TABLE_B" MODIFY ("ID" NOT NULL ENABLE);Edited by: davebcast on Oct 1, 2012 8:51 PM
Index name incorrect
Edited by: davebcast on Oct 1, 2012 8:52 PM

Performance problem using distributed query

Hi,
Can anyone provide an explanation/solution to the following problem encountered on an 8.1.7 database:
SELECT /*+ DRIVING_SITE(vs) */
vs.col2
,user_defined_function
FROM v_remote_table_1 vs
,v_remote_table_2 vc
,local_table_1 s
WHERE vp.col1 = vs.col1
AND s.col1 = vs.col2
AND vs.col2 = &some_val
This generalised query joins two tables in a remote database schema to a table in the local database schema and returns a single row. Without the call to the local user defined function, my specific query returns the row in less than a second. As soon as I include any local user defined function call, even a call to a dummy function which simply returns a string, my query takes several minutes to return its row. Explain plan gives exactly the same plan for both versions of the query, but the statistics are different:
Version without call to function
================================
8 recursive calls
0 db block gets
7 consistent gets
0 physical reads
0 redo size
235 bytes sent via SQL*Net to client
311 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
Version with call to function
=============================
93 recursive calls
4 db block gets
109 consistent gets
1998 physical reads
0 redo size
288 bytes sent via SQL*Net to client
312 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
2 sorts (memory)
2 sorts (disk)
1 rows processed
I'm assuming that, when calling a local function, the DRIVING_SITE hint is ignored, but I don't know why. It's quite important that we are able to include the results of function calls in the query. Any ideas as to the cause of the degraded performance and possible solutions to it would be most welcome!
Thanks.....

I would try something like:
SELECT r.col2,user_defined_function
FROM (SELECT vs.col2
      FROM v_remote_table_1 vs, v_remote_table_2 vp
      WHERE vp.col1 = vs.col1 AND
            vs.col2 = &some_val) r,
     local_table_1 s
WHERE s.col1 = r.col2Thismay allow Oracle to better seperate the calls to the two databases.
HTH
John

Select Performance problems using the 'like' operator

I have a PL/SQL procedure that uses a cursor which contains a 'like' operator in the where clause. I have two database instances that are theoretically the same, however this code processes about 100,000 rows in 5 minutes on one database and 100,000 rows in several weeks on the other database. I know it is the 'like' operator that is causing the problem, but I don't know where to look in the database setup parameters as to what could be different between the two. Can someone point me in the right direction?

I tried to think of another way to write the query, but I really need to use the wildcard option on the data I'm searching for. The system I'm working with attaches a suffix to the end of every ID (ie. '214-222-1234-0') The suffix ('-0') increments but the rest of the ID stays the same ('-1','-2',etc...), but I want to find all of the rows where the first 12 characters are the same, so I strip off the suffix and use a wildcard '%' in its place. I tried adding the SUBSTR() function to the left hand column of the where clause, but it was even slower than using the 'like' operator. I know its a sound query, I just can't figure out why it works fine on one database and not the other.

Performance problem using wwsec_api.is_user_in_group

Hello,
In our PL/SQL code, we using the wwsec_api.is_user_in_group to know in which group is the current user :
This is the code we're using :
AdminNatGroupId := portal.wwsec_api.group_id(upper('vw_admin'));
AnimComGroupId := portal.wwsec_api.group_id(upper('vw_animcom'));
AnimProjGroupId := portal.wwsec_api.group_id(upper('vw_animproj'));
if ( portal.wwsec_api.is_user_in_group(portal.wwctx_api.get_user_id,AdminNatGroupId) ) then
end if ;
Since we have insert 18,000 users in OID, the performances became very, very bad !!!!!
WHY ?
Is there anybody who have an idea ?
Luc.

Your snippet worked fine in PL/SQL on 10.1.2.
l_is_member is a BOOLEAN which is not allowed in SQL, but is allowed in PL/SQL. Although I would expect a different error.
The following dynamic page worked for me:
<HTML>
<HEAD>
<TITLE>Example</TITLE>
</HEAD>
<BODY>
<H2>Example of A Dynamic Page</H2>
<ORACLE>
DECLARE
user_sn NUMBER;
group_sn NUMBER;
l_is_member BOOLEAN;
BEGIN
htp.p('user = ' || :userid);htp.br;
htp.p('group = ' || :groupname);htp.br;
user_sn := wwsec_api.id (:userid);
group_sn := wwsec_api.group_id (:groupname);
l_is_member := wwsec_api.is_user_in_group(
p_person_id => user_sn,
p_group_id => group_sn
IF l_is_member
THEN
htp.p('User ' || :userid || ' is a member of ' || :groupname);
ELSE
htp.p('User ' || :userid || ' is NOT a member of ' || :groupname);
END IF;
exception
when wwsec_api.USER_NOT_FOUND_EXCEPTION
then
htp.p('USER_NOT_FOUND_EXCEPTION');
when wwsec_api.GROUP_NOT_FOUND_EXCEPTION
then
htp.p('GROUP_NOT_FOUND_EXCEPTION');
when wwsec_api.VALUE_ERROR_EXCEPTION
then
htp.p('VALUE_ERROR_EXCEPTION');
when wwsec_api.LDAP_CONNECTION_EXCEPTION
then
htp.p('LDAP_CONNECTION_EXCEPTION');
when wwsec_oid.MULTIPLE_MATCHES_FOUND
then
htp.p('wwsec_oid.MULTIPLE_MATCHES_FOUND');
END;
</ORACLE>
</BODY>
</HTML>

Diff Using and changing in Perform

Hi All,
       What is the difference betwen USING and CHANGING in Perform.
Thanks in advance
                                              Ranjith

hi,
Using helps to use the parameter value passed.
Changing helps to change the parameter value and then use the same in main program with changed value.
Sample:
data : val1 type i value 1,
       val2 type i value 0.
perform calc using val1 changing val2.
Write / : 'Changing :' , val2.
write / : 'Using :' , val1.
*&      Form calc
      text
     -->P_VAL1 text
     <--P_VAL2 text
form calc using    p_val1
           changing p_val2.
p_val2 = p_val1 + 100.
*p_val1 = p_val1 + 100.
*Since p_val1 is passed as using,the above is not *permitted
endform.                    " calc
This link will clear all your Doubts reagrding Perform Statement.
Have a look:
http://help.sap.com/saphelp_erp2005/helpdata/en/9f/db977635c111d1829f0000e829fbfe/frameset.htm
rgds
anver

Using and changing

Hi sir,
what is the diff b/w using and changing keywords for passing the perameters to subroutine and form

Hi ,
   By default if you pass a varaible as Using , you cannot change the value of it in the subroutine but in case of chianging it can be.
Now you can pass the value of using paramater by pass by value , it allows you to change the value in the subroutine but once you are out of the subroutine the changed value is lost and the original value is retained.
So in case you want to change value of a parameter you are passing to a subroutine use changing and if you just want to use its value then use using.
Here is a code which might help you understand it better
REPORT .
data : one type i ,
        two type i.
        one = 1.
        two = 1.
perform chnage_value using one
                     changing two.
write /: one , two.
*&      Form chnage_value
      text
     -->P_ONE text
     <--P_TWO text
form chnage_value using value(p_one)
                  changing p_two.
p_one = p_one + 1.
p_two = p_two + 1.
endform.                    " chnage_value
regards
Arun

Performance problem using on change

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