topic Re: Regarding buffering in Application Development and Automation Discussions

Regarding buffering

spandana_babu — Wed, 24 Dec 2008 10:18:06 GMT

in which case i can use the buffering with select statement

Thanks & Regards

Spanadna

Re: Regarding buffering

Former Member — Wed, 24 Dec 2008 10:26:31 GMT

Hi,

Normally for master data SAP will have a buffer copy of the database table contents in application server itself. So if you write a SELECT for that table SAP will fetch data from buffer. If you want explicitly fetch from database with out using buffer you need to specify BY PASSING BUFFER in the SELECT.

Thanks,

Srinath S

Re: Regarding buffering

Subhankar — Wed, 24 Dec 2008 10:29:43 GMT

Hi....

If a table is buffer table then use by the statement BYPASSING BUFFER. Check the Technical Settings.

Sample code

select count(*)

up to 1 rows

bypassing buffer

from t001w "Plants/Branches

where

werks in s_werks.

Re: Regarding buffering

Former Member — Wed, 24 Dec 2008 10:29:55 GMT

HI.

Refer this link.

http://help.sap.com/saphelp_nwce10/helpdata/en/a7/6e9fff3a08c64f960a29966ecdb9ec/content.htm

Regards.

Jay

Re: Regarding buffering

Former Member — Wed, 24 Dec 2008 10:34:43 GMT

Hello,

Sometimes, even after some data is changes, the older values get displayed. This is because the select statement selects data from a buffer. This has been done to improve system performance.

In case you are facing problems and the updated value does not show up, the buffer can be bypassed.

Regards,

Nimish

Re: Regarding buffering

Former Member — Wed, 24 Dec 2008 10:36:16 GMT

Hi,

Buffering is useful only if table needs to be accessed more no. of times in a program.

Whether buffering is useful, can only be decided depending on the volume of data and the contents.

If the the table data which u r retrieving through select query is used frequently then use buffering else

in technical settings u can mention buffering is allowed or not

Thanks,

Vinod

Re: Regarding buffering

Former Member — Wed, 24 Dec 2008 10:57:46 GMT

you can use buffering in cases the data in DB is not changed frequently.

Usually for extracting transactional data, you dont use buffering as it changes frequently

Re: Regarding buffering

Former Member — Wed, 24 Dec 2008 11:56:48 GMT

Hi ,

Table buffering increases the performance when the records of the table are read.

The records of a buffered table are read directly from the local buffer of the application server on which the accessing transaction is running when the table is accessed. This eliminates time-consuming database accesses. The access improves by a factor of 10 to 100.

When you decide whether a table should be fully buffered, you must take the table size, the number of read accesses and the number of write accesses into consideration. The smaller the table is, the more frequently it is read and the less frequently it is written, the better it is to fully buffer the table.

Advantages and disadvantages of this method of buffer synchronization:

Advantage: The load on the network is kept to a minimum. If the buffers were to be synchronized immediately after each modification, each server would have to inform all other servers about each modification to a buffered table via the network. This would have a negative effect on the performance.

Disadvantage: The local buffers of the application servers can contain obsolete data between the moments of synchronization.

This means that:

Only those tables which are written very infrequently (read mostly) or for which such temporary inconsistencies are of no importance may be buffered.

Regards,

Radhika.