Re: Stack overflow issue

On Thu, Mar 7, 2024 at 12:52 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Alexander Korotkov <aekorotkov(at)gmail(dot)com> writes:
> > The revised set of remaining patches is attached.
> > ...
> > 0003 Avoid recursion in MemoryContext functions
> > I've renamed MemoryContextTraverse() => MemoryContextTraverseNext(),
> > which I think is a bit more intuitive. Also I fixed
> > MemoryContextMemConsumed(), which was still trying to use the removed
> > argument "print" of MemoryContextStatsInternal() function.
>
> This patch still doesn't compile for me --- MemoryContextMemConsumed
> got modified some more by commit 743112a2e, and needs minor fixes.
>
> I initially didn't like the definition of MemoryContextTraverseNext
> because it requires two copies of the "process node" logic. However,
> that seems fine for most of the callers, and even where we are
> duplicating logic it's just a line or so, so I guess it's ok.
> However, MemoryContextTraverseNext seems undercommented to me, plus
> the claim that it traverses in depth-first order is just wrong.
>
> I found some bugs in MemoryContextStatsInternal too: the old
> logic assumed that ichild exceeding max_children was the only
> way to get into the summarization logic, but now ichild minus
> max_children could very well be negative. Fortunately we can
> just reset ichild to zero and not worry about having any
> connection between the first loop and the second.
>
> Here's a v5 of 0003 with those issues and some more-cosmetic ones
> cleaned up. I didn't look at 0001 or 0002.
>

Tom, thank you for your revision of this patch!

Sorry for tediousness, but isn't pre-order a variation of depth-first order
[1]?

Links.
1. https://en.wikipedia.org/wiki/Tree_traversal#Depth-first_search

------
Regards,
Alexander Korotkov