How to compute the ADABAS buffer efficiency

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1

Hi all,
I need assistance to corretly determine the buffer efficiency (BE) of my current ADARUN session. Please see following snapshot from SYSAOS:


                  Physical            ---------- Call Distribution ----------
            Reads          Writes     Remote Logical .............          0
          -------------------------   Remote Physical ............   19407220
ASSO       778923228      163152797   Local  Logical .............          0
DATA      1176890892       24803150   Local  Physical ............  781628077
WORK          716809      145485735   ADASTAR own ................          0
PLOG                       92768560   ADASTAR other ..............          0
                                                                             
Logical Reads ........    664271670   Logical Reads (binary) .....   2797FB36
Buffer Efficiency ....          0.0   No. of HQEs active .........          8
                                      No. of UQEs in User Queue ..        122

Of course, my BE is not 0.0, this may be related to the old release numbers of either SYSAOS or ADABAS :wink:
However, it is possible to correctly compute the BE using the above numbers. But how is the exact formula?

b.t.w. the LBP-parm for that session is at 30 MB!

Thanks in advance,
Ralf Geritz

2

If AOS doesn’t give you the correct numbers, issue a DSTAT operator command against your database and it’ll give you something like:

ADAN17 01196 2006-09-27 14:21:51 Read I/Os A=94,D=4,W=3
ADAN17 01196 2006-09-27 14:21:51 Write I/O A=17,D=5,W=22
ADAN17 01196 2006-09-27 14:21:51 Nr. of commands=818,Buffer efficiency=1052.1
ADAN17 01196 2006-09-27 14:21:51 Nr. of Fmt-Tran.=13,Nr. of Fmt-Ovwr.=0
ADAN17 01196 2006-09-27 14:21:51 Thread001=818 commands
ADAN41 01196 2006-09-27 14:21:51 Function completed

3

Hi Wolfgang,
thx for the quick response. After issuing a DSTAT operator command, I realized, that the buffer efficiency is really at 0 (ZERO)!! So SYSAOS gave me the correct numbers :wink:
What are the experiences in other companies regarding a low BE? I think this is not common for a production environment. Please remember also, the associated LBP parameter is at 30M!
What are your recommendations for increasing the LBP parameter, is there anything to consider since the host-OS is BS2000 and the release levels are rather old (see SIG).
Any comments are welcome!

Thanks, Ralf

4

Please check if you have fixes AN22161 and AN22221 applied.

They talk about incorrect B.E. calculation with a high number of commands (which you have).