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List:       pgsql-hackers
Subject:    Re: [BUG] Autovacuum not dynamically decreasing cost_limit and cost_delay
From:       Scott Mead <scott () meads ! us>
Date:       2023-01-31 15:35:54
Message-ID: CAJsHxiBauvYyJYtEtUy40aTZz+R5nYFwcTJWxknMmerpHQfJRQ () mail ! gmail ! com
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On Mon, Jan 23, 2023 at 12:33 PM Alvaro Herrera <alvherre@alvh.no-ip.org>
wrote:

> On 2021-Feb-08, Mead, Scott wrote:
>
> > Hello,
> >    I recently looked at what it would take to make a running autovacuum
> > pick-up a change to either cost_delay or cost_limit.  Users frequently
> > will have a conservative value set, and then wish to change it when
> > autovacuum initiates a freeze on a relation.  Most users end up
> > finding out they are in ‘to prevent wraparound' after it has happened,
> > this means that if they want the vacuum to take advantage of more I/O,
> > they need to stop and then restart the currently running vacuum (after
> > reloading the GUCs).
>
> Hello, I think this has been overlooked, right?  I can't find a relevant
> commit, but maybe I just didn't look hard enough.  I have a feeling that
> this is something that we should address.  If you still have the cycles,
> please consider posting an updated patch and creating a commitfest
> entry.
>

Thanks!  Yeah, I should be able to get this together next week.


>
> Thanks
>
> --
> Álvaro Herrera         PostgreSQL Developer  —
> https://www.EnterpriseDB.com/
> "Someone said that it is at least an order of magnitude more work to do
> production software than a prototype. I think he is wrong by at least
> an order of magnitude."                              (Brian Kernighan)
>


-- 
--
Scott Mead
*scott@meads.us <scott@meads.us>*

[Attachment #3 (text/html)]

<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" \
class="gmail_attr">On Mon, Jan 23, 2023 at 12:33 PM Alvaro Herrera &lt;<a \
href="mailto:alvherre@alvh.no-ip.org">alvherre@alvh.no-ip.org</a>&gt; \
wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px \
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On 2021-Feb-08, Mead, \
Scott wrote:<br> <br>
&gt; Hello,<br>
&gt;      I recently looked at what it would take to make a running autovacuum<br>
&gt; pick-up a change to either cost_delay or cost_limit.   Users frequently<br>
&gt; will have a conservative value set, and then wish to change it when<br>
&gt; autovacuum initiates a freeze on a relation.   Most users end up<br>
&gt; finding out they are in ‘to prevent wraparound' after it has happened,<br>
&gt; this means that if they want the vacuum to take advantage of more I/O,<br>
&gt; they need to stop and then restart the currently running vacuum (after<br>
&gt; reloading the GUCs).<br>
<br>
Hello, I think this has been overlooked, right?   I can&#39;t find a relevant<br>
commit, but maybe I just didn&#39;t look hard enough.   I have a feeling that<br>
this is something that we should address.   If you still have the cycles,<br>
please consider posting an updated patch and creating a commitfest<br>
entry.<br></blockquote><div><br></div><div>Thanks!   Yeah, I should be able to get \
this together next week.    </div><div>  </div><blockquote class="gmail_quote" \
style="margin:0px 0px 0px 0.8ex;border-left:1px solid \
rgb(204,204,204);padding-left:1ex"> <br>
Thanks<br>
<br>
-- <br>
Álvaro Herrera              PostgreSQL Developer   —   <a \
href="https://www.EnterpriseDB.com/" rel="noreferrer" \
target="_blank">https://www.EnterpriseDB.com/</a><br> &quot;Someone said that it is \
at least an order of magnitude more work to do<br> production software than a \
prototype. I think he is wrong by at least<br> an order of magnitude.&quot;           \
(Brian Kernighan)<br> </blockquote></div><br clear="all"><div><br></div>-- <br><div \
dir="ltr" class="gmail_signature"><div dir="ltr"><div>--</div><div>Scott \
Mead</div><div><span style="color:rgb(68,68,68)"><i><a href="mailto:scott@meads.us" \
target="_blank">scott@meads.us</a></i></span><br></div></div></div></div>



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