Re: Can avoid list_copy in recomputeNamespacePath() conditionally?

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От amul sul
Тема Re: Can avoid list_copy in recomputeNamespacePath() conditionally?
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Msg-id CAAJ_b94aokxZBDqR+B0EZn21pgd5ES+-cFKdp8KY2UWUDT5D0A@mail.gmail.com
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Ответ на Re: Can avoid list_copy in recomputeNamespacePath() conditionally?  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-hackers
On Sat, Nov 2, 2019 at 8:01 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
amul sul <sulamul@gmail.com> writes:
> I wondered can we have a shortcut somewhat similar to following POC
> in recomputeNamespacePath () when the recomputed path is the same as the
> previous baseSearchPath/activeSearchPath :
> +   /* TODO: POC */
> +   if (equal(oidlist, baseSearchPath))
> +       return;

There's an awful lot missing from that sketch; all of the remaining
steps still need to be done:


You are correct, but that was intentionally skipped to avoid longer post
descriptions for the initial discussion. Sorry for being little lazy.
 
        baseCreationNamespace = firstNS;
        baseTempCreationPending = temp_missing;

        /* Mark the path valid. */
        baseSearchPathValid = true;
        namespaceUser = roleid;

        /* And make it active. */
        activeSearchPath = baseSearchPath;
        activeCreationNamespace = baseCreationNamespace;
        activeTempCreationPending = baseTempCreationPending;

        /* Clean up. */
        pfree(rawname);
        list_free(namelist);
        list_free(oidlist);

More to the point, I think the onus would be on the patch submitter
to prove that the extra complexity had some measurable benefit.
I really doubt that it would, since the list_copy is surely trivial
compared to the catalog lookup work we had to do to compute the OID
list above here.

Agree.
 
It'd likely be more useful to see if you could reduce the number of
places where we have to invalidate the path in the first place.

Understood, let me check.

Regards,
Amul 

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