Kernel parameter for large concurrent connections database.

Question

Hi,
Does any one have suggestion about kernel parameters we have to modify for large concurrent connections database (about 20000 concurrent connections) ? We would like to use Sun M8000 as our database server. Oracle installation guide indicated many parameters and values, but it seems ok for general database, not the one we need. Please somebody help us. Thanks !

Answer 1

I certainly don't have any idea where the 150G memory usage for 20000 concurrent users come about. That's 7.5MB per user session.
The session memory usage is depends on Oracle version, OS , Database configuration and application behavior etc..
From following query we can tell, average session memory usage is around 1.5M in normal usage on 10g linux platform.
It could go up to 20-30M if user session doing large data manipulation.
SYS@test >  l
  1   select value, n.name|| '('||s.statistic#||')' , sid
  2    from v$sesstat s , v$statname n
  3    where s.statistic# = n.statistic#
  4    and n.name like '%ga memory%'
  5*   order by sid
SYS@azerity > /
     VALUE N.NAME||'('||S.STATISTIC#||')'        SID
    486792 session pga memory max(26)             66
    486792 session pga memory(25)                 66
    225184 session uga memory(20)                 66
    225184 session uga memory max(21)             66
    225184 session uga memory max(21)             70
    486792 session pga memory max(26)             70
    486792 session pga memory(25)                 70
    225184 session uga memory(20)                 70
    225184 session uga memory(20)                 72
    486792 session pga memory max(26)             72
    225184 session uga memory max(21)             72
    486792 session pga memory(25)                 72
    486792 session pga memory max(26)             74
    225184 session uga memory(20)                 74
    486792 session pga memory(25)                 74
    225184 session uga memory max(21)             74
......Aggregate by SID
  1   select sum(value),sid
  2    from v$sesstat s , v$statname n
  3    where s.statistic# = n.statistic#
  4    and n.name like '%ga memory%'
  5    group by sid
  6*   order by sid
SYS@test > /
SUM(VALUE)        SID
   1423952         66
   1423952         70
   1423952         72
   1423952         74
   1423952         75
   1423952         77
   1423952         87
   1423952        101
   2733648        104
   1423952        207
  23723248        209
  23723248        210
   1293136        215
   7370320        216
.........