Re: Memory Accounting v11

On 7 July 2015 at 18:59, Jeff Davis <pgsql@j-davis.com> wrote:

 

> One other thing that I don't remember seeing discussed would be to
> just store a List in each context which would store all of the
> mem_allocated's that need to be updated during each allocation and
> deallocation of memory. The list would be setup once when the context
> is created. When a child context is setup we'd just loop up the parent
> context chain and list_concat() all of the parent's lists onto the
> child's lists. Would this method add too much overhead when a context
> is deleted? Has this been explored already?
>
That's a good idea, as it would be faster than recursing. Also, the
number of parents can't change, so we can just make an array, and that
would be quite fast to update. Unless I'm missing something, this sounds
like a nice solution. It would require more space in MemoryContextData,
but that might not be a problem.

Oh an array is even better, but why more space? won't it just be a pointer to an array? It can be NULL if there's nothing to track. Sounds like it would be the same amount of space, at least on a 64 bit machine.