OPtimizing Performance for Select query on huge table

Hi All,
   We are fetching a single record from NAST table. The table has around 10 Million Entries.
   The Select Query takes around 5-6 minutes to return.
   We are not using the Primary key completely. We are using only one field of the primary key.
    The field is also a part of the Index but we are not using all the fields in the index as well.
    We need to bring down the time. What can be the solution? I cant see any changes to the code, since its a single query and we cant use the Entire Primary key.
   Would creating an Index on the fields that we are concerned with help in this regard.
   Open to all solutions.
Thanks in Advance,
Imran

There are sometimes tricks you can use to get it to use the index more efficiently. If you let us know which fields you are using in the SELECT (all of them actually), we might be able to help.
Or are you saying you can't change the code at all?
Please don't create duplicate posts though.
Rob
Message was edited by:
Rob Burbank

Similar Messages

OPtimizing Performance for Select query on NAST table

Hi All,
   We are fetching a single record from NAST table. The table has around 10 Million Entries.
   The Select Query takes around 5-6 minutes to return.
   We are not using the Primary key completely. We are using only one field of the primary key.
    The field is also a part of the Index but we are not using all the fields in the index as well.
    We need to bring down the time. What can be the solution? I cant see any changes to the code, since its a single query and we cant use the Entire Primary key.
   Would creating an Index on the fields that we are concerned with help in this regard.
   Open to all solutions.
Thanks in Advance,
Imran

Hi,
Please check this thread
http://sap.ittoolbox.com/documents/popular-q-and-a/specifying-the-index-to-be-used-2462
For creating another secondary index in NAST whether basis will approve for this?
aRs

Select query on a table with 13 million of rows

Hi guys,
I have been trying to perform a select query on a table which has 13 millions of entries however it took around 58 min to complete.
The table has 8 columns with 4 Primary keys looks like below:
(PK) SegmentID > INT
(PK) IPAddress > VARCHAR (45)
MAC Address > VARCHAR (45)
(PK) Application Name > VARCHAR (45)
Total Bytes > INT
Dates > VARCHAR (45)
Times > VARCHAR (45)
(PK) DateTime > DATETIME
The sql query format is :
select ipaddress, macaddress, sum(totalbytes), applicationname , dates,
times from appstat where segmentid = 1 and datetime between '2011-01-03
15:00:00.0' and '2011-01-04 15:00:00.0' group by ipaddress,
applicationname order by applicationname, sum(totalbytes) desc
Is there a way I can improve this query to be faster (through my.conf or any other method)?
Any feedback is welcomed.
Thank you.
Mus

Tolls wrote:
What db is this?
You never said.
Anyway, it looks like it's using the Primary Key to find the correct rows.
Is that the correct number of rows returned?
5 million?
Sorted?I am using MySQL. By the way, the query time has been much more faster (22 sec) after I changed the configuration file (based on my-huge.cnf).
The number of rows returned is 7999 Rows
This is some portion of the my.cnf
# The MySQL server
[mysqld]
port = 3306
socket = /var/lib/mysql/mysql.sock
skip-locking
key_buffer = 800M
max_allowed_packet = 1M
table_cache = 256
sort_buffer_size = 1M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size= 16M
log = /var/log/mysql.log
log-slow-queries = /var/log/mysqld.slow.log
long_query_time=10
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 6
Is there anything else I need to tune so it can be faster ?
Thanks a bunch.
Edited by: user578505 on Jan 17, 2011 6:47 PM

Creating SELECT query between 3 tables

Hi there,
Im trying to create a SELECT query between 3 tables and it is driving me round the bend.
I have 3 tables connected together which are:
MODUL
modulid
modulname
modulevel
STUDENT
studentid
surname
inits
s e x
phone
email
logon
STUDREGOCCUR
modulid
acyear
semester
occletter
studentid
result
I want to select the fields surname, inits, studentid from the STUDENT table, modulname from the MODUL table and result from my STUDREGOCCUR table that is NOT NULL.
I have tried SELECT STUDENT.STUDENTID, STUDENT.INITS, STUDENT.SURNAME, MODUL.MODULNAME, STUDREGOCCUR.RESULT WHERE STUDREGOCCUR.RESULT IS NOT NULL;
I have also tried many other ways and done research hwich hasnt really helped me unfortunately.
Im quite new to SELECT queries and im not sure where im going wrong, i would greatly appreciate if someone could help me solve my problem.
Thanks for the help :)
Edited by: user633643 on 06-Dec-2008 08:09

If you want data from multiple tables you would need to perform a join. The general form would be:
select t1.cola, t2.col2, t3.col.x
from table_a a, table_b b, table_c c
where a.key = b.key
and b.key = c.key
or perhaps c relates back directly to a so it is a.key = c.key where key can be any column whose value is equilivent in what it represents to the value it is being compared to, that is, student_number = student_number or the columns regardless of name are both building numbers, room numbers, etc ....
This is not your exact solution but it should help.
HTH -- Mark D Powell --

CV04N takes long time to process select query on DRAT table

Hello Team,
While using CV04N to display DIR's, it takes long time to process select query on DRAT table. This query includes all the key fields. Any idea as to how to analyse this?
Thanks and best regards,
Bobby
Moderator message: please read the sticky threads of this forum, there is a lot of information on what you can do.
Edited by: Thomas Zloch on Feb 24, 2012

Be aware that XP takes approx 1gb of your RAM leaving you with 1gb for whatever else is running. MS Outlook is also a memory hog.
To check Virtual Memory Settings:
Control Panel -> System
System Properties -> Advanced Tab -> Performance Settings
Performance Options -> Adavanced Tab - Virtual Memory section
Virtual Memory -
what are
* Initial Size
* Maximum Size
In a presentation at one of the Hyperion conferences years ago, Mark Ostroff suggested that the initial be set to the same as Max. (Max is typically 2x physical RAM)
These changes may provide some improvement.

How to perform a select op on a table whose name is contained by a variable

I am using Oracle SQL*Plus client.
declare
tablename_var varchar(10); LOOK HERE
date_var date;
begin
select sysdate
into date_var
from &tablename_var; LOOK HERE
dbms_output.put_line('The system date is '||date_var);
end;
The above code prompts the user to enter a value for the variable tablename_var, once the user enters 'dual' on prompt... The system date is given as output.
declare
tablename_var varchar(10):='dual'; LOOK HERE
date_var date;
begin
select sysdate
into date_var
from tablename_var; LOOK HERE
dbms_output.put_line('The system date is '||date_var);
end;
This code fails and gives an error. I understand. Engine interprets it as... trying to perform a select operation on a variable, and says a table or a view is expected.
Can someone please tell me what to do, to perform a select operation on a table whose name is contained by a variable, like above?

Hi,
Welcome to the forum!
You need Dynamic SQL if the table- or column names are variables.
Getting the current date isn't a good example; you could get that without a query simply by saying
date_var := SYSDATE;Also, SELECT ... INTO will raise an error if the query does not return exactly 1 row.
In the example below, let's get the latest entry_date from a given table:
For example:
declare
     tablename_var     varchar(10);
     date_var      date;
     sql_txt           VARCHAR2 (1000);
begin
     tablename_var := 'table_x;
     sql_txt := 'select MAX (entrydate)'
          || ' from ' || tablename_var;
     dbms_output.put_line (sql_txt || ' = sql_txt');    -- Not essential, but recommended
     EXECUTE IMMEDIATE sql_txt INTO date_var;
     dbms_output.put_line ('The latest entry_date is ' || date_var);
end;Dynamic SQL involves creating a string that contains the SQL statement. Displaying the string is purely optional, of course, but it's a very good idea when writing and de-bugging code. Remember to comment-out or delete the display before moving the code into Production.
For an exercise, make the column name a variable, instead of the hard-coded entry_date.
Edited by: Frank Kulash on Nov 5, 2009 9:20 AM

Is it worth using select query on infotype tables

Hi Experts,
I might be posting in the wrong column, but i just need to know is it worth using a select query on Infotype tables (PAxxxx)?? or should we prefer using the function modules for data fetching?
If select is not suggested, what is the reason for that?
Rgds
Prateek

Hi ,
Its not said that u cant write select on PAXXXX tables . Yes of couse LDB are there to fetch the data but it depends on
the requirement when to write a select and when to consider using in LDB .
Generally when you are looking at say 8 to 10 tables of infotypes with free selection , then LDB is suggested to fetch the data .
if you are looking to fetch the data for say some tables for a restricted selection (where clause) then select is used .
If i want to write a program using select only then fetching data from infotypes tables for large no of records will lead to
more time consumption which becomes easier in LDB as they are fetched in hierarchy level based on keys .
Normally it will be a combination of LDB and select querys in the development scenario
Br,
Vijay.

Select Query on TCURR table

Hello All,
I am writing select query on TCURR table , but unable to get the values from table though i cansee the entries in table for the same condition as i provided int he program .
Is there an peculiar reason for the sme .
MY query is as follows.
SELECT * FROM tcurr INTO TABLE g_t_tcurr
                                 WHERE kurst = 'M'                             AND fcurr = g_f_waers
                             AND tcurr = 'AUD'
                             AND gdatu LE l_f_datum (MKPF-BUDAT).
Any help is appreciated .
Thanks

Hi,
Please check the datatype and try again...
data:
         DATC(8)       TYPE C,
         GDATU_OLD(8) TYPE C.
*exc_type = 'M'.
SELECT * FROM tcurf into table g_t_tcurr
CLIENT SPECIFIED
           WHERE kurst       = exc_type
           AND    fcurr       = for_curr
           AND    tcurr       = loc_curr
           AND    gdatu      GE datc
           AND    mandt       = mandt
           ORDER BY PRIMARY KEY.
FM: CONVERT_TO_LOCAL_CURRENCY_N can be used to convert the amt from local currency to Foreign currency.
Regds
Parvathi

How to insert the select query result into table?

How to insert the select query result into table?
SELECT top 20 creation_time
,last_execution_time
,total_physical_reads
,total_logical_reads
,total_logical_writes
, execution_count
, total_worker_time
, total_elapsed_time
, total_elapsed_time / execution_count avg_elapsed_time
,SUBSTRING(st.text, (qs.statement_start_offset/2) + 1,
((CASE statement_end_offset
WHEN -1 THEN DATALENGTH(st.text)
ELSE qs.statement_end_offset END
- qs.statement_start_offset)/2) + 1) AS statement_text
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) st
ORDER BY total_elapsed_time / execution_count DESC;
Thanks,
Tirumala

1. SELECT INTO
Below method will create table when data is inserted from one table to another table. Its useful when you need exactly same datatype as source table.
Use AdventureWorks2008R2;
Go
---Insert data using SELECT INTO
SELECT AddressLine1, City
INTO BothellAddresses
FROM Person.Address
where City = 'Bothell';
GO
---VERIFY DATA
Select AddressLine1, City
FROM BothellAddresses
---DROP TABLE
DROP TABLE BothellAddresses
GO
2. INSERT INTO SELECT
Below method will need table to be created prior to inserting data. Its really useful when table is already created and you want insert data from
another table.
Use AdventureWorks2008R2;
Go
---Create Table
CREATE TABLE BothellAddresses (AddressLine1 NVARCHAR(60), City NVARCHAR(30))
---Insert into above table using SELECT
INSERT INTO BothellAddresses(AddressLine1, City)
SELECT AddressLine1, City
FROM Person.Address
where City = 'Bothell';
---VERIFY DATA
Select AddressLine1, City
FROM BothellAddresses
---DROP TABLE
DROP TABLE BothellAddresses
GO
Regards,
Vishal Patel
Blog: http://vspatel.co.uk
Site: http://lehrity.com

Dynamic Select Query including Dynamic Tables with For all Entries

Hello everyone,
I need to create a select query which involves using of Dynamic Tables.
Suppose I have a dynamic table <d1> which consist of let say 10 records.
Now i need to make a select query putting data into another dynamic table <d2>
CONCATENATE keyfield '=' '<d1>' INTO g_condition SEPARATED BY space.
CONCATENATE g_condition '-' keyfield INTO g_condition.
SELECT * FROM (wa_all_tables-name) INTO CORRESPONDING FIELDS OF TABLE <d1>
        FOR ALL ENTRIES IN <d1>
WHERE (g_condition).
But it is giving dump.
Please help me on this....

Short text
    A condition specified at runtime has an unexpected format.
What happened?
    Error in the ABAP Application Program
    The current ABAP program "ZNG_CUSTOMWRITE" had to be terminated because it has
    come across a statement that unfortunately cannot be executed.
Error analysis
    An exception occurred that is explained in detail below.
    The exception, which is assigned to class 'CX_SY_DYNAMIC_OSQL_SEMANTICS', was
     not caught in
    procedure "WRITE_ARCHIVE_PROD" "(FORM)", nor was it propagated by a RAISING
     clause.
    Since the caller of the procedure could not have anticipated that the
    exception would occur, the current program is terminated.
    The reason for the exception is:
    The current ABAP program has tried to execute an Open SQL statement
    which contains a WHERE, ON or HAVING condition with a dynamic part.
    The part of the WHERE, ON or HAVING condition specified at runtime in
    a field or an internal table, contains the invalid value "ZCOURIER-ZCOURIERID".
CONCATENATE keyfield '=' g_header INTO g_condition SEPARATED BY space.
CONCATENATE g_condition '-' keyfield INTO g_condition.
SELECT * FROM (wa_all_tables-name) INTO CORRESPONDING FIELDS OF TABLE <dyn_table1>
FOR ALL ENTRIES IN <dyn_table>
WHERE (g_condition).

How to assign table name for select query in loop.

Hi friends my requirement is count the no of records of all the database table which comes into an internal table ."Check the below coding". Iam fetching the tables from dd03l table into an internal table .plz give me a sujjesion how to assign a table name in select query in a loop.
SELECT tabname FROM dd09l
            INTO TABLE i_dd09l
            WHERE protokoll = 'X'.
IF sy-subrc = 0.
    SORT i_dd09l BY tabname.
ENDIF.
LOOP AT i_dd09l.
    SELECT COUNT(*) INTO val FROM i_dd09l-tabname.
    IF sy-subrc = 0.
      i_dd09l-count = val.
    ENDIF.
    MODIFY i_dd09l INDEX sy-index.
    CLEAR val.
ENDLOOP.
error : 'I_DD09L-TABNAME' is not defined in the abap dictionary as a table.

data: dy_table type ref to data,
      dy_line type ref to data,
      xfc type lvc_s_fcat,
      ifc type lvc_t_fcat,
      dy_field type ref to data.
LOOP AT i_dd09l.
perform get_structure using i_dd09l-tabname .
CREATE DATA dy_table TYPE TABLE OF (_dd09l-tab_name).
    UNASSIGN <dyn_table>.
    ASSIGN dy_table->* TO <dyn_table>.
SELECT COUNT(*) INTO val FROM <dyn_table>.
IF sy-subrc = 0.
i_dd09l-count = val.
ENDIF.
MODIFY i_dd09l INDEX sy-index.
CLEAR val.
ENDLOOP.
form get_structure using p_table.
data : idetails type abap_compdescr_tab,
xdetails type abap_compdescr.
data : ref_table_des type ref to cl_abap_structdescr.
Get the structure of the table.
ref_table_des ?=
cl_abap_typedescr=>describe_by_name( p_table ).
idetails = ref_table_des->components.
loop at idetails into xdetails.
    clear xfc.
    xfc-fieldname = xdetails-name .
    xfc-datatype = xdetails-type_kind.
    xfc-inttype = xdetails-type_kind.
    xfc-intlen = xdetails-length.
    xfc-decimals = xdetails-decimals.
    append xfc to ifc.
endloop.
endform.                    "get_structure
Try like this hope it will work.
Regards,
madan.

Performance improvement for select query

Hi all,
need to improve performace for the below select query as it is taking long time
SELECT vbeln pdstk
         FROM vbuk INTO TABLE it_vbuk1 FOR ALL ENTRIES IN it_likp
      WHERE vbeln = it_likp-vbeln       AND
            wbstk = 'C' AND "pdstk = ' ' AND
            vbtyp IN gr_delivery AND
            ( fkstk = 'A' OR fkstk = 'B' ) OR
            ( fkivk = 'A' OR fkivk = 'B' ).
Regards,
Kumar

Hi,
    Check if it_likp is sorted on vbeln.
SELECT vbeln pdstk
FROM vbuk INTO TABLE it_vbuk1 FOR ALL ENTRIES IN it_likp
WHERE vbeln = it_likp-vbeln AND
wbstk = 'C' AND
vbtyp IN gr_delivery AND
( ( fkstk = 'A' OR fkstk = 'B' ) OR      <-- check this condition , if ( ) is needed ...
( fkivk = 'A' OR fkivk = 'B' ) ) .
Regards,
Srini.

Regarding to perform in select query

could any tell the select query in this piece of code would affect the performance of the programe
DATA: BEGIN OF OUTREC,
      BANKS LIKE BNKA-BANKS,
      BANKL LIKE BNKA-BANKL,
      BANKA LIKE BNKA-BANKA,
      PROVZ LIKE BNKA-PROVZ,   "Region (State, Province, County)
      BRNCH LIKE BNKA-BRNCH,
      STRAS LIKE BNKA-STRAS,
      ORT01 LIKE BNKA-ORT01,
      SWIFT LIKE BNKA-SWIFT,
END OF OUTREC.
OPEN DATASET P_OUTPUT FOR OUTPUT IN TEXT MODE.
IF SY-SUBRC NE 0. EXIT. ENDIF.
SELECT * FROM BNKA
         WHERE BANKS EQ P_BANKS
         AND   LOEVM NE 'X'
         AND   XPGRO NE 'X'
         ORDER BY BANKS BANKL.
PERFORM TRANSFER_DATA.
ENDSELECT.
CLOSE DATASET P_OUTPUT.
*&      Transfer the data to the output file
FORM TRANSFER_DATA.
OUTREC-BANKS = BNKA-BANKS.
OUTREC-BANKL = BNKA-BANKL.
OUTREC-BANKA = BNKA-BANKA.
OUTREC-PROVZ = BNKA-PROVZ.
OUTREC-BRNCH = BNKA-BRNCH.
OUTREC-STRAS = BNKA-STRAS.
OUTREC-ORT01 = BNKA-ORT01.
OUTREC-SWIFT = BNKA-SWIFT.
TRANSFER OUTREC TO P_OUTPUT.
ENDFORM.                               " READ_IN_DATA

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.
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 # 13
SORT 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.

ST05 Trace on a select query on BSEG table

hi all,
this is my select query on table BSEG table:
SELECT bukrs
         belnr
         gjahr
         buzei
         KOART
         mwskz
         kostl
         lifnr
         aufnr
         werks
         ebeln
         txjcd
         projk FROM bseg
               INTO TABLE i_bseg
               FOR ALL ENTRIES IN i_ad_tab
              WHERE bukrs EQ i_ad_tab-bukrs AND
                    belnr EQ i_ad_tab-belnr AND
                    gjahr EQ i_ad_tab-gjahr.
when i m doing SQL trace ST05 on this query and in the detail statement showed the following query
SELECT
"MANDT" , "BUKRS" , "BELNR" , "GJAHR" , "PAGENO" , "TIMESTMP" ,
"PAGELG" , "VARDATA"
FROM
"RFBLG"
WHERE
"MANDT" = ? AND "BUKRS" = ? AND "BELNR" = ? AND "GJAHR" = ?
ORDER BY
"MANDT" , "BUKRS" , "BELNR" , "GJAHR" , "PAGENO"
what is RFBLG table in SE11, but could not find it.
what is RFBLG?also, the above select query giving me performance issues.. the "for all entries" clause is used as per norms...
please suggest a solution..

hi
good
The famous BSEG table is a cluster table.
It is as was correctly stated part of the Accounting Document Segment. It is part of the Pool cluster RFBLG and lives in the package: FBAS (Financial accounting 'Basis').
You can't read a cluster table exactly the way you read a database (old speak, transparent table).
You can use a program to read called RFPPWF05
Note 435694: Display BSEG item by calling FB09D (modified FB09)
Other possiblity: Other possibility: CALL DIALOG 'RF_ZEILEN_ANZEIGE', but since this is a dialog I don't think this would work.
In any event go to FBAS Package (development class) to see your business objects, class library and functions.
you must use keyfields bukrs , belnr, gjahr
(so 1st select table bkpf) to select bseg.
or use secondary index tables:
bsas, bsis, bsik, bsak, bsid, bsad
Regards,
Raj.

Select query on QALS table taking around 4 secs to fetch one record

Hi,
I have one select query that takes around 4 secs to fetch one record. I would like to know if there are any ways to reduce the time taken for this select.
SELECT
     b~prueflos
     b~matnr
     b~lagortchrg
     a~vdatum
     a~kzart
     a~zaehler
     a~vcode
     a~vezeiterf
     FROM qals AS b LEFT OUTER JOIN qave AS a ON
     bprueflos = aprueflos
     INTO TABLE t_qals1
     FOR ALL ENTRIES IN t_lgorts
      WHERE matnr = t_lgorts-matnr
      AND    werk = t_lgorts-werks
      AND    lagortchrg = t_lgorts-lgort
      AND    stat35 = c_x
      AND    art IN (c_01,c_08).
When I took the SQL trace, here I found other details :
Column          No.Of Distinct Records
MANDANT                                      2
MATNR                                      2.954
WERK                                          30
STAT34                                         2
HERKUNFT                                   5
Analyze Method                    Sample 114.654 Rows
Levels of B-Tree                                 2
Number of leaf blocks                         1.126
Number of distinct keys                      16.224
Average leaf blocks per key                1
Average data blocks per key               3
Clustering factor                                  61.610
Also note, This select query is using INDEX RANGE SCAN QALS~D.
All the suggestions are welcome
Regards,
Vijaya

Hi Rob,
Its strange but, the table t_lgorts has only ONE record
MATNR = 000000000500003463
WERK = D133
LAGORTCHRG   = 0001
I have also seen that for the above criteria the table QALS has 2266 records that satisfy this condition.
I am not sure..but if we write the above query as subquery instead of Outer join..will it improve the performance?
Will check it from my side too..
Regards,
Vijaya

OPtimizing Performance for Select query on huge table

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