Re: POC: converting Lists into arrays - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: POC: converting Lists into arrays
Date
Msg-id CAH2-Wz=bLMnTM0SHDvrdBXdRom2XZrXxZvcS8SaFLMOfQTFkzg@mail.gmail.com
Whole thread Raw
In response to Re: POC: converting Lists into arrays  (Bruce Momjian <bruce@momjian.us>)
List pgsql-hackers
On Mon, Mar 4, 2019 at 2:04 PM Bruce Momjian <bruce@momjian.us> wrote:
> On Mon, Mar  4, 2019 at 12:44:41PM -0500, Robert Haas wrote:
> > I think that's a separate but also promising thing to attack, and I
> > agree that it'd take a lot of work to get there.  I don't think that
> > the problem with either parse-tree-copying or list usage is that no
> > performance benefits are to be had; I think it's that the amount of
> > work required to get those benefits is pretty large.  If it were
> > otherwise, somebody likely would have done it before now.
>
> Stupid question, but do we use any kind of reference counter to know if
> two subsystems look at a structure, and a copy is required?

No, but I wonder if we could use Valgrind to enforce rules about who
has the right to scribble on what, when. That could make it a lot
easier to impose a new rule.

-- 
Peter Geoghegan


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