Re: setting memory_target < memory_max_target
Date: Mon, 1 Dec 2014 17:57:56 +0100
Message-Id: <9155BC37-0C91-43EF-B6E0-8D4E17A98210_at_gmail.com>
So you have some memory left which is not worn-out when you need it.
No, you are right: it doesn’t make sense on most platforms. I believe on solaris the memory is truly allocated if you start using it, not during allocation time, so setting memory_target smaller than memory_max_target results in using only the amount specified by memory_target, so indeed you have spare memory left you can use.
At the end, it still means you save memory, even on solaris, which doesn’t make sense to me; it makes way more sense to allocate the resources you have in your system, instead of saving them, from a performance perspective.
But it also doesn’t make sense to me to use memory_target, because it can’t use huge pages (outside of solaris).
Frits Hoogland
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> On 01 Dec 2014, at 17:49, Zwettler Markus (OIZ) <Markus.Zwettler_at_zuerich.ch> wrote:
>
> Is there any reason why anyone would set memory_target < memory_max_target?
>
> It doesn’t make sense to me because why shouldn’t the database use all allocated memory? Why should anyone save allocated memory for later?
>
> Thanks, Markus
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