I'd like to understand what hides behind the SHM Key 41 (DB statistics buffer) on ABAP AS. Why can it grow from a couple of Mbs to GBs ? Is there any parameter setting to control it ?
Generally shared memory sizes can't change their size during runtime, they are created when the application starts. However, some OS'ses (Solaris) can do that neverless using DISM.
I agree that they are calculated at start and (in some condtions on some OSes) they can grow. I wanted to know if there is a parameter for this specific buffer ? and btw what is it for ?
OK for the pool 40: If I enlanrge the CUA too much (setting rsdb/cua/buffersize parameter higher), I might have to modify the pool size ALSO (setting ipc/shm_psize_40 higher like requested by SAPPFPAR) because CUA is contained in the pool 40.
In my case, the pool value is 0 (ipc/shm_psize_41=0). But the size of "DB statistics buffer" is 13 MB on the system I am working on now.
Unlike the "classical" buffers like the CUA which is contained (in my case) in the pool 40, this one is out of pool and that's why it has an onw ID exactly in the same way as the PXA buffer who has the pool ID 06.
To modify the PXA buffer size you chage the abap/buffersize parameter and not ipc/shm_psize_06. And I am looking for the "real parameter" or the influencing factor for "DB statistics buffer" and not just the IPC SHM parameter.
Do you see what I mean ? (My explanation might still be confusing .. sorry for that)
> Unlike the "classical" buffers like the CUA which is contained (in my case) in the pool 40, this one is out of pool and that's why it has an onw ID exactly in the same way as the PXA buffer who has the pool ID 06.
> To modify the PXA buffer size you chage the abap/buffersize parameter and not ipc/shm_psize_06. And I am looking for the "real parameter" or the influencing factor for "DB statistics buffer" and not just the IPC SHM parameter.
I understand your issue
On one of our systems:
Pool 40:
Shared memories inside of pool 40
Key: 42 Size: 19552992 ( 18.6 MB) DB TTAB buffer
Key: 43 Size: 38999736 ( 37.2 MB) DB FTAB buffer
Key: 44 Size: 11715256 ( 11.2 MB) DB IREC buffer
Key: 45 Size: 8304312 ( 7.9 MB) DB short nametab buffer
Key: 46 Size: 20480 ( 0.0 MB) DB sync table
Key: 47 Size: 6657024 ( 6.3 MB) DB CUA buffer
Key: 48 Size: 500000 ( 0.5 MB) Number range buffer
Key: 49 Size: 2968344 ( 2.8 MB) Spool admin (SpoolWP+DiaWP)
Shared memories outside of pools
<...>
Key: 41 Size: 25010000 ( 23.9 MB) DB statistics buffer
<...>
In the developer trace I see
B Wed Dec 1 23:38:50 2010
B dbstat: table statistics switched on for 34857 tables
B dbstat: TABSTAT buffer created (addr: 0x2c4d5d1000, size: 17176536)
B db_con_shm_ini: WP_ID = 0, WP_CNT = 51, CON_ID = -1
Don't know whether this is the correct segment/key/object buffer...
I'd open an OSS call for this (BC-CST-MM) if you think this is a problem.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.