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Home -> Community -> Usenet -> c.d.o.server -> Re: 2GB limit for SGAs
Chloe Crowder wrote:
> Hi
>
> We're running 32-bit 8.1.7 on 64-bit SunOS 5.8. We have two databases
> and one Oracle installation. Someone has been trying to tell me that
> there is a 2GB limit on the total size of the SGA, i.e. (database 1
> SGA + database 2 SGA) must be less than 2GB. Is this correct?
>
> I quite understand that there's a architectural limit per SGA, but I'm
> really surprised about a total limit.
Hi,
of course there is a limit of the sga size of each database running a
32bit oracle version. But the 2 (or more sga) do not interfere with the
size of the other instances sgas (given that the unix kernel parameter
are set properly and there is enough ram).
The 32bit address limit is 4GB (not 2gb), but the address range has to
be split into kernel and user address range. The split is highly
processor and OS dependent.
On solaris (32 and 64 bit), it's no problem to use a 3GB sga with 32bit
oracle (see below. You can clearly see that the sga is ~2.8GB with
oracle 9.2 32bit).
Regards
Stephan
$ file $ORACLE_HOME/bin/oracle
/oracle/FSP1/orav92_32/bin/oracle: ELF 32-bit MSB executable SPARC
Version 1, dynamically linked, not stripped
$ uname -a
SunOS mybox 5.8 Generic_108528-29 sun4us sparc FJSV,GPUSC-M
$sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.2.0 - Production on Thu May 27 07:53:29 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to an idle instance.
SQL> startup nomount
ORACLE instance started.
Total System Global Area 2814465276 bytes
Fixed Size 455932 bytes Variable Size 1174405120 bytes Database Buffers 1638400000 bytes Redo Buffers 1204224 bytesSQL> exit
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