That is what I thought too. But apparently quite a few people are using high SGA and Sharedpool in their databases. Looks like we can use big SGAs and shared pools without negative side effects. I did not get to see the response times or performance reports of this database that I saw; maybe it is good. On Mon, Apr 19, 2010 at 2:21 PM, Marcin Przepiorowski <pioro1@xxxxxxxxx>wrote: > Hi, > > I have always think that if you increasing shared pool to enormous > size like 22 GB > you are generating more problems for database and decrease performance due > to > long time spend on shared pool management - did you ever try to > decrease shared pool > to 2 or 3 GB ? > How many SQL with plans are you keep in shared pool ? how much pl/sql > code do you have ? > and maybe first of all what version do you have ? > > regards, > -- > Marcin Przepiorowski > http://oracleprof.blogspot.com > > > On Fri, Apr 16, 2010 at 8:13 AM, LS Cheng <exriscer@xxxxxxxxx> wrote: > > Hi > > > > I configured one a few weeks ago with 48G SGA and 22GB shared pool for a > > DWH. > > > > I think I hit some bug that is why I need to set the shared pool so large > > because this is a 6 nodes RAC and whenever shared pool is under pressure > > process LCK starts to free shared pool memory (observed from v$rowcache > and > > v$sgastat) and holds the shared pool latch which cause hang in the node > > (sometimes the entire system, all 6 nodes). Previously I had shared pool > set > > to 8GB and the hang situation happened everyday (many times instance > dies), > > when I increased to 22GB it only happens like once every couple of weeks. > > > > v$rowcache shows 7 million entries, anyone seen larger than that? I am > > really curious. > > > > > > Thanks > > > > -- > > LSC > > > > > > > > > > On Fri, Apr 16, 2010 at 3:55 AM, Ram Raman <veeeraman@xxxxxxxxx> wrote: > >> > >> > >> I saw a big database today with an SGA size of 56GB and a shared pool of > >> 12Gb. The SGA_TARGET was set to 0. This database size is a few > terabytes. I > >> have not heard of such big SGA or SP sizes. I thought having big memory > >> sizes may cause latch contention and CPU issues. > >> > >> What is the maximum SGA and SP sizes of DBs that you have seen. > >> > >> Thanks. > > > > > > -- >