Re: ALTER TABLE ADD COLUMN fast default

On Tue, Mar 13, 2018 at 10:58 PM, Andrew Dunstan
<andrew.dunstan@2ndquadrant.com> wrote:
> On Tue, Mar 13, 2018 at 2:40 PM, Andrew Dunstan
> <andrew.dunstan@2ndquadrant.com> wrote:
>
>>>
>>> Going by the commitfest app, the patch still does appear to be waiting
>>> on Author. Never-the-less, I've made another pass over it and found a
>>> few mistakes and a couple of ways to improve things:
>>>
>>
>> working on these. Should have a new patch tomorrow.
>>
>
>
> Here is a patch that attends to most of these, except that I haven't
> re-indented it.
>
> Your proposed changes to slot_getmissingattrs() wouldn't work, but I
> have rewritten it in a way that avoids the double work you disliked.
>
> I'll rerun the benchmark tests I posted upthread and let you know the results.
>

Here are the benchmark results from the v15 patch. Fairly similar to
previous results. I'm going to run some profiling again to see if I
can identify any glaring hotspots. I do suspect that the "physical
tlist" optimization sometimes turns out not to be one. It seems
perverse to be able to improve a query's performance by dropping a
column.

cheers

andrew


-- 
Andrew Dunstan                https://www.2ndQuadrant.com
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