Re: Process memory behaviour of Oracle

From: Robert Klemme <>
Date: Mon, 14 Jan 2008 23:00:59 +0100
Message-ID: <>

On 14.01.2008 19:41, wrote:
> On Jan 14, 6:21 pm, "Jonathan Lewis" <>
> wrote:

>> The presentation and notes at the following URL may help:
>> --
>> Regards
>> Jonathan Lewis

> Thanks Jonathan!
> In the meantime I have also noted the following: when I check v
> $pgastats I notice a huge entry for memory freed/released to OS
> (suspiciously close to the 10G I released earlier) - I am guessing
> that Oracle "holds on" to PGA memory for a while and does not let the
> OS have it back ?
> From what I understand of the Linux memory allocator it masks system
> brk() calls inside the library malloc() for efficiency reaons so
> perhaps Oracle does something similar ? But one problem I have is that
> the SGA sometimes has problems acquiring memory (I see this in the
> stack trace of a Java OJDBC driver when it tries to set up connections
> etc.) even though my own C program does not (i.e., I believe the
> memory is there to be had)
> ...but first I must study your link!

Some additional food for thought:

Kind regards

        robert Received on Mon Jan 14 2008 - 16:00:59 CST

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