Re: Seeking reason behind performance gain in 12 with HashAggregate

--000000000000fe1c48059c0b8b8e
Content-Type: text/plain; charset="UTF-8"

Hi Michael,

I appreciate your question. I ran a vacuum analyze on the 9.6 table and it
yielded no difference. Same number of buffers were read, same query plan.

Thanks,
Shira

On Mon, Jan 13, 2020 at 10:07 AM Michael Lewis <[email protected]> wrote:

> I am not at all familiar with PostGIS so perhaps this is a silly question,
> is bloat an issue on the older instance? Correlation isn't causation, but
> half the buffers scanned and half the runtime in the v12 plan has me
> curious why that might be.
>
>>

-- 
Shira Bezalel
Database Administrator & Desktop Support Manager
San Francisco Estuary Institute
www.sfei.org
Ph: 510-746-7304

--000000000000fe1c48059c0b8b8e
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div class=3D"gmail_default" style=3D"font-family:tahoma,s=
ans-serif">Hi Michael,</div><div class=3D"gmail_default" style=3D"font-fami=
ly:tahoma,sans-serif"><br></div><div class=3D"gmail_default" style=3D"font-=
family:tahoma,sans-serif">I appreciate your question. I ran a vacuum analyz=
e on the 9.6 table and it yielded no difference. Same number of buffers wer=
e read, same query plan.</div><div class=3D"gmail_default" style=3D"font-fa=
mily:tahoma,sans-serif"><br></div><div class=3D"gmail_default" style=3D"fon=
t-family:tahoma,sans-serif">Thanks,</div><div class=3D"gmail_default" style=
=3D"font-family:tahoma,sans-serif">Shira</div><br><div class=3D"gmail_quote=
"><div dir=3D"ltr" class=3D"gmail_attr">On Mon, Jan 13, 2020 at 10:07 AM Mi=
chael Lewis &lt;<a href=3D"mailto:[email protected]" target=3D"_blank">mle=
[email protected]</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" s=
tyle=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);pad=
ding-left:1ex"><div dir=3D"ltr"><div>I am not at all familiar with PostGIS =
so perhaps this is a silly=C2=A0question, is bloat an issue on the older in=
stance? Correlation isn&#39;t causation, but half the buffers scanned and h=
alf the runtime in the v12 plan has me curious why that might be.</div><div=
 class=3D"gmail_quote"><blockquote class=3D"gmail_quote" style=3D"margin:0p=
x 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
</blockquote></div></div>
</blockquote></div><br clear=3D"all"><div><br></div></div>-- <br><div dir=
=3D"ltr"><div dir=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr"><div>=
<div><font color=3D"#666666" face=3D"tahoma, sans-serif" size=3D"2">Shira B=
ezalel=C2=A0</font></div><div><font color=3D"#666666" face=3D"tahoma, sans-=
serif" size=3D"2">Database Administrator &amp; Desktop Support=C2=A0</font>=
<span style=3D"color:rgb(102,102,102);font-family:tahoma,sans-serif;font-si=
ze:small">Manager</span></div><div><font color=3D"#666666" face=3D"tahoma, =
sans-serif" size=3D"2">San Francisco Estuary Institute</font></div><div><fo=
nt color=3D"#666666" face=3D"tahoma, sans-serif" size=3D"2"><a href=3D"http=
://www.sfei.org" target=3D"_blank">www.sfei.org</a></font></div><div><font =
color=3D"#666666" face=3D"tahoma, sans-serif" size=3D"2">Ph: 510-746-7304</=
font></div></div><div style=3D"font-weight:bold;font-style:normal;font-vari=
ant:normal;line-height:20px;margin:0px"><br style=3D"color:rgb(0,0,0);font-=
family:Tahoma;font-size:13px;font-weight:normal;line-height:normal"></div>
<div style=3D"padding-top:8px">
	=C2=A0</div></div></div></div></div></div></div>

--000000000000fe1c48059c0b8b8e--