Re: Memory Accounting v11

On 14 June 2015 at 23:51, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:

> The current state, where HashAgg just blows up the memory, is just not
>>> reasonable, and we need to track the memory to fix that problem.
>>>
>>
>> Meh. HashAgg could track its memory usage without loading the entire
>> system with a penalty.
>>
>
> +1 to a solution like that, although I don't think that's doable without
> digging the info from memory contexts somehow.
>
>>
Jeff is right, we desperately need a solution and this is the place to
start.

Tom's concern remains valid: we must not load the entire system with a
penalty.

The only questions I have are:

* If the memory allocations adapt to the usage pattern, then we expect to
see few memory chunk allocations. Why are we expecting "the entire system"
to experience a penalty?

* If we do not manage our resources, how are we certain this does not
induce a penalty? Not tracking memory could be worse than tracking it.

--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
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