Re: Sun box runs out of swap when starting Oracle

From: vsevolod afanassiev <vsevolod.afanassiev_at_gmail.com>
Date: Mon, 26 Sep 2011 17:24:08 -0700 (PDT)
Message-ID: <c7486974-e077-412f-bc5d-d995232d7c73_at_i33g2000yqm.googlegroups.com>



After reading a bit more on the subject I've found that Oracle uses DISM (Dynamic ISM) pages,
this can be seen using "pmap -sx":

0000000380000000 4096 4096 - - 4M rwxs- [ dism shmid=0x16 ]
0000000380400000 15822848 - - - - rwxs- [ dism shmid=0x16 ]
0000000746000000 180224 180224 - - 4M rwxs- [ dism shmid=0x16 ]
0000000751000000 8192 8192 - - - rwxs- [ dism shmid=0x16 ]
0000000751800000 8192 8192 - - 4M rwxs- [ dism shmid=0x16 ]

There is Solaris paper "Dynamic Reconfiguration and Oracle9i Dynamically Resizable SGA",
it states that Oracle 9i uses DISM if SGA size > size of its components which is true in our case.

Experimenting with another database that has 1 GB SGA I was able to get it to use ISM instead of DISM
after increasing db_cache_size:

000000010362C000 8 8 8 - 8K rwx-- [ heap ]
0000000380000000 1069056 1069056 - 1069056 4M rwxsR [ ism shmid=0x2000036 ]
FFFFFFFF7D100000 8 8 8 - 8K rwx-- [ anon ]
FFFFFFFF7D102000 8 - - - - rwx-- [ anon ] Received on Mon Sep 26 2011 - 19:24:08 CDT

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