topic Re: interview Question on perfomance tunning in Application Development and Automation Discussions

interview Question on perfomance tunning

Former Member — Mon, 21 Apr 2008 08:29:35 GMT

hi abaper's

if for all entries is taking more time to retriew data from DDIC , then how can we improve performance which type of select statement we have to use.

and i need some notes on Performace tunning.

regards

pardeep kumar

Re: interview Question on perfomance tunning

Former Member — Mon, 21 Apr 2008 08:34:11 GMT

Hi,

If it is taking more time, then check

1. if the internal table used in the for all entries is not empty.

2. if the internal table used in for all entries does not have any duplicate entries.

Inspite of the above checks, the for all entries is taking more time...then

try to use Join and make sure you use primary keys as joining fields.

Regards,

Madhumitha

Re: interview Question on perfomance tunning

Former Member — Mon, 21 Apr 2008 08:51:25 GMT

Please have a look at below link for performane tuning tips:

https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/5d0db4c9-0e01-0010-b68f-9b1408d5f234

I hope it helps.

Thanks,

Vibha

Please mark all the useful answers

Re: interview Question on perfomance tunning

Former Member — Mon, 21 Apr 2008 10:31:45 GMT

Hi,

Factors affecting the performance of FOR ALL ENTRIES:-

1) If the table on which the For All Entries IN clause is based is empty, then all rows are selected into the destination table. which may take lot of time move all the rows into the destination table. to avoid this check in before whether the first internal table is empty or not.

2) If the table on which the For All Entries IN clause is based is very large, then also the performance of the FOR ALL ENTRIES may get affected. Hence care should be taken to keep internal table size at a moderate level.

Hope this may help you to solve your problem.

Cheers,

Re: interview Question on perfomance tunning

Former Member — Mon, 21 Apr 2008 15:07:50 GMT

incorrect usage of FOR ALL ENTRIES:

if the driver table is empty, and you don't want to get the whole db-table back. Please take care that the FOR ALL ENTRIES is only executed if the driver table contains records.

(side remark: don't check with describe table lines, you don't need the number of lines, only whether it is not initial)

if the driver table can contain a lot of duplicates, then sort it and delete duplicates before execution. Duplicates means with respect to the fields which are used in the select. If the driver table is needed later and has actually a longer unique key, then it is necessary to move into a temporary table and remove the duplicates there.

performant usage of the FOR ALL ENTRIES:

the select must be able to use an index, otherwise performance will be bad, if the table is large.

Optimization of a correct performant FOR ALL ENTRIES statement:

Check whether the same can be achivied by a join, the join can be more performant than the FOR ALl ENTRIES.

Siegfried

Re: interview Question on perfomance tunning

Former Member — Tue, 22 Apr 2008 07:52:11 GMT

while using FOR ALL ENTRIES you have to make sure the internal table which you are using must not be blank if it is than it will fetch all the entries from the selected table which cause to dump or performance of the program will descreased.

secondly check for duplicate entries and remove them.

And make sure while selecting you can provide as many as key fields or indexed fields, this will improve the performance as well.

reward if helps.