Oracle on NT4 memory use

[Holger Knust]

We upgraded a server from 512MB to 2.5GB due to performance issues. The
server still uses ca. 512MB of physical memory. The total commit charge is
1.8GB. Physical Memory available is about 2GB.

I've read about NT's 2GB/2GB problem, but I am not sure whether that is the
cause.

The main problem are most likely inefficient queries, but I would like to
maximize Oracle's memory use in the mean time. If I see 2GB of RAM free, I
would like to put them to use.

Any ideas?

Thanks,

Holger

[sybrandb@yahoo.com]

Re: Oracle on NT4 memory use

"Holger Knust" <knusth@bellsou th.netwrote in message news:<TZOMa.610 3$Sy1.3837@fe02 .atl2.webusenet .com>...

We upgraded a server from 512MB to 2.5GB due to performance issues. The
server still uses ca. 512MB of physical memory. The total commit charge is
1.8GB. Physical Memory available is about 2GB.
>
I've read about NT's 2GB/2GB problem, but I am not sure whether that is the
cause.
>
The main problem are most likely inefficient queries, but I would like to
maximize Oracle's memory use in the mean time. If I see 2GB of RAM free, I
would like to put them to use.
>
Any ideas?
>
Thanks,
>
Holger

You won't be able to use the 2G. By design NT uses 50 percent of the
memory for O/S purposes. Hence Oracle recommends to use only 1/3 of
physical memory for the SGA. See the relevant documents on NT
architecture on Metalink.
You should address the root cause instead of fighting symptoms.
Generally speaking increasing the size of the SGA also increases
paging and swapping. All Oracle hitratio's 99 percent and your OS will
be suffocating.

Sybrand Bakker
Senior Oracle DBA

[Holger Knust]

Re: Oracle on NT4 memory use

My next question would be: SGA 1/3 of the physical memory available (2.5GB)
or 1/3 of 500MB that NT leaves to apps?

I will go after the queries but that will take some time.

Thanks,

Holger

<sybrandb@yahoo .comwrote in message
news:a1d154f4.0 307030158.93dba b3@posting.goog le.com...

"Holger Knust" <knusth@bellsou th.netwrote in message

news:<TZOMa.610 3$Sy1.3837@fe02 .atl2.webusenet .com>...

We upgraded a server from 512MB to 2.5GB due to performance issues. The
server still uses ca. 512MB of physical memory. The total commit charge

is

1.8GB. Physical Memory available is about 2GB.

I've read about NT's 2GB/2GB problem, but I am not sure whether that is

the

cause.

The main problem are most likely inefficient queries, but I would like

to

maximize Oracle's memory use in the mean time. If I see 2GB of RAM free,

I

would like to put them to use.

Any ideas?

Thanks,

Holger

>
>
You won't be able to use the 2G. By design NT uses 50 percent of the
memory for O/S purposes. Hence Oracle recommends to use only 1/3 of
physical memory for the SGA. See the relevant documents on NT
architecture on Metalink.
You should address the root cause instead of fighting symptoms.
Generally speaking increasing the size of the SGA also increases
paging and swapping. All Oracle hitratio's 99 percent and your OS will
be suffocating.
>
Sybrand Bakker
Senior Oracle DBA

[Nuno Souto]

Re: Oracle on NT4 memory use

"Holger Knust" <knusth@bellsou th.netwrote in message news:<WzWMa.753 4$eW6.3367@fe03 .atl2.webusenet .com>...

My next question would be: SGA 1/3 of the physical memory available (2.5GB)
or 1/3 of 500MB that NT leaves to apps?

That sounds very weird. You sure you tuned NT for application server?
Looks like you left it at file server, then it uses up as much
mem as it can for file cache. You running Server, aren't you?
Not Workstation! And SP6?
You should have a LOT more than 500Mb free to apps in app server
mode.

>
I will go after the queries but that will take some time.
>

Good luck.


Cheers
Nuno Souto
wizofoz2k@yahoo .com.au.nospam