Re: Thinking about inventing MemoryContextSetParent

Excerpts from Tom Lane's message of sáb sep 10 19:03:23 -0300 2011:
> I'm considering inventing a new mcxt.c primitive,
> 
> void MemoryContextSetParent(MemoryContext context, MemoryContext new_parent);
> 
> which would have the effect of delinking "context" from its current
> parent context and attaching it as a child of the new specified parent.
> (Any child contexts that it has would naturally follow along.)
> Because of the way that mcxt.c handles parent/child links, there is no
> palloc required and so the operation cannot fail.

Interesting.  I wonder whether we could use this somehow to fix
performance problems in certain subtransaction code paths that "reassign
stuff to the parent"; instead of moving pointers or memory around,
perhaps we could do something like this.  Not that I have actually
looked into it.

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Álvaro Herrera <alvherre@commandprompt.com>
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