topic JOIN Alias name. in Application Development and Automation Discussions

JOIN Alias name.

vinod_vemuru2 — Wed, 05 Mar 2008 06:41:38 GMT

Hi Guys,

I am doing analysis on Performance improvement. when we are using JOINS is it better to use short alias name or Long alias name.

Surprisingly i am getting better performance for long alias name. resulting time is the average of 100 executions.

Please check below code.

TYPES: Begin of t_vbrk,

vbeln TYPE vbrk-vbeln,

fkart TYPE vbrk-fkart,

vbtyp TYPE vbrk-vbtyp,

vkorg TYPE vbrk-vkorg,

erdat TYPE vbrk-erdat,

zuonr TYPE vbrk-zuonr,

posnr TYPE vbrp-posnr,

meins TYPE vbrp-meins,

fklmg TYPE vbrp-fklmg,

ntgew TYPE vbrp-ntgew,

gewei TYPE vbrp-gewei,

matnr TYPE vbrp-matnr,

vkbur TYPE vbrp-vkbur,

END OF t_vbrk.

DATA: i_vbrk TYPE STANDARD TABLE OF t_vbrk,

w_before TYPE i,

w_after TYPE i,

w_delta TYPE i.

GET RUN TIME FIELD w_before.

SELECT vbrk_{vbeln vbrk}fkart vbrk_{vbtyp vbrk}vkorg

vbrk_{erdat vbrk}zuonr vbrp_{posnr vbrp}meins

vbrp_{fklmg vbrp}ntgew vbrp_{gewei vbrp}matnr

vbrp~vkbur

INTO TABLE i_vbrk

FROM vbrk AS vbrk INNER JOIN vbrp AS vbrp

ON vbrk_{vbeln EQ vbrp}vbeln

WHERE vbrk~vbeln LT '0005021899'.

GET RUN TIME FIELD w_after.

w_delta = ( w_after - w_before ) / 100000.

WRITE:/1 'With Long alias name', w_delta.

CLEAR: w_before, w_after, w_delta.

GET RUN TIME FIELD w_before.

SELECT a_{vbeln a}fkart a_{vbtyp a}vkorg

a_{erdat a}zuonr b_{posnr b}meins

b_{fklmg b}ntgew b_{gewei b}matnr b~vkbur

INTO TABLE i_vbrk

FROM vbrk AS a INNER JOIN vbrp AS b

ON a_{vbeln EQ b}vbeln

WHERE a~vbeln LT '0005021899'.

GET RUN TIME FIELD w_after.

w_delta = ( w_after - w_before ) / 100000.

WRITE:/1 'With short alias name', w_delta.

Even i tried interchanging the position of the select statements.

This select will fetch around 24000+ records in my system.

Please suggest whether this is the right way to do the performance analysis.

Thanks,

Vinod.

Re: JOIN Alias name.

Former Member — Wed, 05 Mar 2008 06:47:26 GMT

Hi,

If u want to improve the performance of the program then use for all entries instead of joins, bezc joins reduces the speed of retiveing the data from the Database.

In ur query u used alias, it is used for only to reduce the code length, instead of repeting the same word more no. of times, i thing its nothing related to perfomance.You try with FORALL ENTRIES.

Regards,

kavitha.

Re: JOIN Alias name.

Former Member — Wed, 05 Mar 2008 06:50:27 GMT

Hi,

In the first query, if u use the same alias name as the table name , there is no need of extension 'as vbrk' . It can be given as 'from vbrk join vbrp on' condn.

Regards,

Ramya

Re: JOIN Alias name.

Former Member — Wed, 05 Mar 2008 06:53:22 GMT

Hi,

But this has got nothing to do with the performance. Check if u can reduce the selection time. Use 'for all entries'. Make sure that u check if the itab is not initial before using 'for all entries in itab'.

Regards,

Ramya

Re: JOIN Alias name.

vinod_vemuru2 — Wed, 16 Apr 2008 06:34:38 GMT

Thank u guys