John Cantu, January 17, 2013 - 12:31 pm UTC
Thank you for enlightening me on this important information.
So does the paging cause database performance problems since operating systems are allowed to page out pages from 'shared pool' and 'buffer cache pools'?
Also, regarding the background process memory usage. There is the PGA and the 'other memory associated with the proceses' that you mentioned. Roughly, how much Maximum total physical OS RAM can the 'other memory' can allocated byby all 20+ 11g background processes? Is it like <50M or 50-100M or 500+ M or 1+gB, etc.?
Thank you
January 17, 2013 - 2:17 pm UTC
paging (reading and writing memory to/from disk) affects the performance of everything on the machine more or less (in a negative fashion)
the amount of memory used by the backgrounds varies, you can sum up the pga memory - but you'd have to use an OS utility to measure the other ram used by them. It'll be megabytes typically - not gigabytes.
query on pdbs
jithu, March 15, 2022 - 3:49 pm UTC
Hi
If we execute the sql
elect vs.program, s.sid, sn.name, round( s.value/1024/1024, 2 ) mb
2 from v$statname sn, v$sesstat s, v$session vs
3 where sn.statistic# = s.statistic#
4 and vs.sid = s.sid
5 and sn.name = 'session pga memory'
in the CDB level ,will this provide us with the results of PDB level processes as well.
The actual intend of the question was to find out whether any of our application sessions in any of our pdbs inside the CDB is holding up SGA
Thanks
JIthu
March 16, 2022 - 3:36 am UTC
Yes
SQL> select con_id, count(*)
2 from v$sesstat
3 group by con_id;
CON_ID COUNT(*)
---------- ----------
1 5922
3 1974
0 151998