| From: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> |
|---|---|
| To: | Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: ALTER TABLE ADD COLUMN fast default |
| Date: | 2018-03-14 00:28:35 |
| Message-ID: | CAKJS1f-oW14tJB8iytaND5CJO8kF9gtUQrEc9Unn+g-zuDJPLw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On 14 March 2018 at 11:36, Andrew Dunstan
<andrew(dot)dunstan(at)2ndquadrant(dot)com> wrote:
> 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.
Can you explain what "fdnmiss" is that appears in the results?
--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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