From: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Subject: Re: Should we increase the default vacuum_cost_limit?
To: David Rowley <david.rowley@2ndquadrant.com>,
 Joe Conway <mail@joeconway.com>
Cc: Peter Geoghegan <pg@bowt.ie>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
References: 
 <CAKJS1f_YbXC2qTMPyCbmsPiKvZYwpuQNQMohiRXLj1r=8_rYvw@mail.gmail.com>
 <CAH2-Wz=WQ9ju6sjPF7RcW0g6NPXAenZeC5qVme6uj+eMRw5q2g@mail.gmail.com>
 <241b80ab-7af0-c606-7b2c-b0a5d6be696a@joeconway.com>
 <CAKJS1f_5xofbg0K16MkhQPeCXV6oGCuD2SVcV76OW7ydFDHDkw@mail.gmail.com>
Openpgp: preference=signencrypt
Autocrypt: addr=andrew.dunstan@2ndQuadrant.com; prefer-encrypt=mutual;
 keydata=
 xsBNBE7KWFkBCAClridxur2AIc7eW2AR7izbfp3EnNefie2HbLF0izW5Ik5UjX2HBXBx4syI
 gY6b0ugohXrr274+baoAlvSbq6cAoQuEVrk5IZFzt20b1Xkx65FwGSEj526yiKLocqkJceSq
 Xr9xcA5SGY+FZv441chh5SU92v4q6z+6LPpoHOh97ptAVXZYNTtU0LevyvD5lja0TzbvJm6C
 eFXitJfnm1pLEr0DGJCR/iUOl/N62Kh4855zZC7NHIjQHPOvV5Stz/l5ilDhvGVk+xkXFPys
 SjZoUr1rXhYLpiyi5sR0X9FHXT0KnGuz1F5ERO7ZTLSSQ6fJwPj6gOk9K+vvoKvoeql5ABEB
 AAHNL0FuZHJldyBEdW5zdGFuIDxhbmRyZXcuZHVuc3RhbkAybmRRdWFkcmFudC5jb20+wsCY
 BBMBAgBCAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUJDyV6hBYhBOQ+WEYd/Hy/RGkV
 pZn6f8tZ/DuBBQJcH/EVAhkBAAoJEJn6f8tZ/DuB7BEH/iDWZEbVft2m2MT6SPjARzTupt/l
 xLLZ/Cl6n2US2hov5+fBbnR5xvECk/YCOfG9ICvKNlpFjceqNLRKStd8cmndnI+kDw91uNM2
 hpL4aJMeW65XCHvqXlOLSwv5chBpXz9NG7FMaJ+q+59sWEWjcTNmjXgkEHn53y+1pc7nSLDe
 cr5ZI1aB3nGXRm1SoDY5PYZkUKMykW+YBZwgcs/Q5tRaE+siN7DKbz8E628+PerwAkmHPVXN
 MdJFD6gs4S0gDFA8IxcyIwZU2v4By+brzcJ9Se3FK5BYxBDHtaYZxgSrJAvOUOrLIZPQTQfL
 TtnVs3C3JTfrxCH1ceHtnA6dRuTOwE0ETspYWQEIANGc4zQULOxhbqO2dyD51YhqCNRmm9oK
 Waqf+wmW4tpDe/VVcxAnNizd4LWCHfzpb5cHAtGkOPePMfzWVf6nvdF7d3eglbtf59+zG7O7
 llV0xSSoFiieQBsrGvqDInXYX/4mRRXMtyhM353/tixC9RWLs1oofyYmCPPXXY7h9R7en3B8
 BoVrRFcdzlIY/NFNhFGW/9dkEiGjgna2Rk6e15kln4ZvFBWUg23p93w/pqXcxY6+k/8TEk+C
 4R+M6w7o2PLGOjdZ+kPiUcw5H85zf/yZJwQXzisXaNduwWB6Vads9YC9dj6kPR1c4VGRqAaY
 L++LAEOqrlvm2TvqQqZRtnEAEQEAAcLAZQQYAQIADwIbDAUCXA6fpAUJDyV6xAAKCRCZ+n/L
 Wfw7geU4B/9vFFsVmWxerDWgNjyiK80zIPmlw/iwdUlU6FIu0JWLMg4093kvxBs7RMZV9hBq
 n3ekBvD4IvFsVLJrw9qzSI2FH3UeYy5WXpEs01Ppia60NOlvRDqXbryzuvfe+iYo6bVP3Ikr
 TPTNYL/BePUTD2DPvSI82SbGTyzuA7SJv6NRqqQDMIy1fU6KyQFLmQJp/QJyhKWzm9jWh8ee
 w8jVaoMY0Kbq5N7RqisEx1Lu/Iw646UphdYzQNymf+kbiU5Kf4I6DhzV8w9sie1Bo1juNj3I
 c5/fFJsmxljbnaDbXPcnFsur1Oo9mIHFakgWgOBMuxoWfjONiLjjLh/9+ZIqSSLX
Message-ID: <df548503-d261-d8c4-97d0-61be6617df41@2ndQuadrant.com>
Date: Tue, 5 Mar 2019 17:14:55 -0500
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.3.0
MIME-Version: 1.0
In-Reply-To: 
 <CAKJS1f_5xofbg0K16MkhQPeCXV6oGCuD2SVcV76OW7ydFDHDkw@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Content-Language: en-MW
Precedence: bulk


On 2/25/19 8:38 AM, David Rowley wrote:
> On Tue, 26 Feb 2019 at 02:06, Joe Conway <mail@joeconway.com> wrote:
>> On 2/25/19 1:17 AM, Peter Geoghegan wrote:
>>> On Sun, Feb 24, 2019 at 9:42 PM David Rowley
>>> <david.rowley@2ndquadrant.com> wrote:
>>>> The current default vacuum_cost_limit of 200 seems to be 15 years old
>>>> and was added in f425b605f4e.
>>>>
>>>> Any supporters for raising the default?
>>> I also think that the current default limit is far too conservative.
>> I agree entirely. In my experience you are usually much better off if
>> vacuum finishes quickly. Personally I think our default scale factors
>> are horrible too, especially when there are tables with large numbers of
>> rows.
> Agreed that the scale factors are not perfect, but I don't think
> changing them is as quite a no-brainer as the vacuum_cost_limit, so
> the attached patch just does the vacuum_cost_limit.
>
> I decided to do the times by 10 option that I had mentioned.... Ensue
> debate about that...
>
> I'll add this to the March commitfest and set the target version as PG12.
>

This patch is tiny, seems perfectly reasonable, and has plenty of
support. I'm going to commit it shortly unless there are last minute
objections.


cheers


andrew


-- 
Andrew Dunstan                https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services