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05627 - buffer synchronization

05627 - buffer synchronization

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buffer synchronization

Hello Jenny,
In a 3-tier environment, each application server (the central instance can
also be an application server) buffers it's own copy of data. When one
application makes a change to the data that is buffered, a record is written
to the dirty data log and the data in the local buffer in the application
server is invalidated. After the time specified in the buffer reference
synchronization time expires, the dirty data log is read and the buffers in
the other application servers in a system are marked as invalid. The next
time the invalid data is requested, the data is reloaded from the database
into the buffer in the application server. Until that time passes, the data
is still read from the buffer and may be outdated. This means that the
application can receive old data. If the application must have the most
current data, the application can avoid this situation by executing SQL
statements that bypass the buffer. This is good from the standpoint of
receiving the most current data in the program. However, this reduces the
effectiveness of the buffering because the buffer is not used for these
statements.

I hope this helps.
Best regards,
Alan

-----Original Message-----
From: Gueldenpfennig, Volker
Sent: Tuesday, April 09, 2002 1:56 AM
To: 'DoNotReply@consolut.eu'
Cc: 'jenny_9406Zh...'
Subject: RE: Re: buffer synchronization


Hi Jenny,

you could use both values - 60 and 120 should work fine. 60 means, that the
system more often checks, which will result in a bit more overhead. With 120
it will happen, that up to 120 s the buffers in the other APPL-server can be
outdated, but it is a less overhead.

You can check this with RZ11.

If you want to change this you could use RZ10. Normally it is set in the
default profile. But it could be in the instance profiles as well.

But be aware, that the bufrefmode is set to sendon/exeauto and NOT to
sendoff/exeauto, as you are running a 3-tier system this would be totally
wrong!
You might want to have a look to note 484548.

Regards

Volker

-----Original Message-----
From: jenny_sun392002 [mailto:jenny_9406Zh...]
Sent: Dienstag, 9. April 2002 06:26
To: DoNotReply@consolut.eu
Subject: Re: buffer synchronization


Hi Alan,

I have seen that you recommend 'buffer reference sync time should be
set to 60 seconds.'.
In notes 14754 I saw another value for the same parameter 'Parameter
rdisp/bufreftime defines the intervals in which buffer invalidation
is carried out. The unit is seconds, the recommended value is 120. '

Could you tell me: which is best in practise? and how could I defined
the value that our system need?


Thanks and Best Regards.

jenny

the --- In SAP on System iZy..., "Olson, Clyde" <clyde.olsonZs...>
wrote:buffer reference sync time should be set to 60 seconds.
> Hello Eric,
> buffer reference sync mode is probably set to sendof,exeauto - it
should be
> sendon,exeauto.
> buffer reference sync time should be set to 60 seconds.
> That should help. By the way, the parameters need to be set the
same on all
> instances.
> Best regards,
> Alan
>
> -----Original Message-----
> From: Erik Huot [mailto:ehuotZs...]
> Sent: Thursday, April 04, 2002 5:00 PM
> To: SAP on System iZy...
> Subject: buffer synchronization
>
>
> Hi every one,
>
> We have a problem and I am sure some of you faced it before.
>
> * User A is working in instance 1. He displays a certain record,
then gets
> out.
> * User B is working in instance 2 of the same SID. He changes
that same
> record, saves it and gets out.
> * User A doesn't see these changes even after a long period of time
(10
> minutes).
>
> Is there any set-up I can modify to accelerate the buffer
synchronization in
> various instances?
>
> Best Regards,
>
> P.S. is sap400Zm... still down?
>
> Erik Huot
> Southshore Industries Ltd
>
>
>
>
> Have a look to our homepage at: http://www.consolut.net
> SAP on System i-unsubscribeZy...
>
> Your use of consolut is subject to
http://www.consolut.net



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