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Date: Fri, 19 Jun 2020 17:03:20 +0800
From: "movead.li@highgo.ca" <movead.li@highgo.ca>
To: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>,
	"Amit Kapila" <amit.kapila16@gmail.com>,
	"Masahiko Sawada" <masahiko.sawada@2ndquadrant.com>
Cc: "Fujii Masao" <masao.fujii@oss.nttdata.com>,
	pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Global snapshots
References: <07b2c899-4ed0-4c87-1327-23c750311248@postgrespro.ru>,
	<4d13207c-43ba-1db3-1459-e7d4bc0e47ad@oss.nttdata.com>,
	<9964cf46-9294-34b9-4858-971e9029f5c7@postgrespro.ru>,
	<CAA4eK1Jo=1261+qEKmm69Bm9wv6fvR7kVbqDo7EFUw3vkQtC7w@mail.gmail.com>,
	<f23083b9-38d0-6126-eb6e-091816a78585@postgrespro.ru>
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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; charse=
t=3DUTF-8"><style>body { line-height: 1.5; }blockquote { margin-top: 0px; =
margin-bottom: 0px; margin-left: 0.5em; }body { font-size: 10.5pt; font-fa=
mily: 'Microsoft YaHei UI'; color: rgb(0, 0, 0); line-height: 1.5; }</styl=
e></head><body>=0A<div><span></span><br></div><div><div>&gt;&gt; would lik=
e to know if the patch related to CSN based snapshot [2] is a</div><div><s=
pan style=3D"font-size: 10.5pt; line-height: 1.5; background-color: transp=
arent;">&gt;</span>&gt; precursor for this, if not, then is it any way rel=
ated to this patch</div><div><span style=3D"font-size: 10.5pt; line-height=
: 1.5; background-color: transparent;">&gt;</span>&gt; because I see the l=
atest reply on that thread [2] which says it is an</div><div><span style=
=3D"font-size: 10.5pt; line-height: 1.5; background-color: transparent;">&=
gt;</span>&gt; infrastructure of sharding feature but I don't understand c=
ompletely</div><div><span style=3D"font-size: 10.5pt; line-height: 1.5; ba=
ckground-color: transparent;">&gt;</span>&gt; whether these patches are re=
lated?</div><div><span style=3D"font-size: 10.5pt; line-height: 1.5; backg=
round-color: transparent;">&gt;</span>I need some time to study this patch=
.. At first sight it is different.</div></div><div><br></div>=0A<div>This p=
atch[2] is almost base on [3],&nbsp;<span style=3D"font-size: 10.5pt; line=
-height: 1.5; background-color: transparent;">because I think [1] is talki=
ng about 2PC</span></div><div><span style=3D"font-size: 10.5pt; line-heigh=
t: 1.5; background-color: transparent;">and FDW, so this patch</span>&nbsp=
;focus on CSN only and<span style=3D"font-size: 10.5pt; line-height: 1.5; =
background-color: transparent;">&nbsp;I detach&nbsp;</span><span style=3D"=
font-size: 10.5pt; line-height: 1.5; background-color: transparent;">the g=
lobal snapshot</span></div><div><span style=3D"font-size: 10.5pt; line-hei=
ght: 1.5; background-color: transparent;">part and FDW part from the [1] p=
atch.&nbsp;</span></div><div><span style=3D"font-size: 10.5pt; line-height=
: 1.5; background-color: transparent;"><br></span></div><div><span style=
=3D"font-size: 10.5pt; line-height: 1.5; background-color: transparent;">I=
 notice CSN&nbsp;</span><span style=3D"font-size: 10.5pt; line-height: 1.5=
; background-color: transparent;">will not&nbsp;survival after a restart i=
n [1] patch, I think it may not the</span></div><div><span style=3D"font-s=
ize: 10.5pt; line-height: 1.5; background-color: transparent;">right way, =
may be it is what in last mail "</span><span style=3D"font-family: 'Micros=
oft YaHei UI', Tahoma; line-height: normal; font-size: 10.5pt; background-=
color: transparent;">Needs guarantees of monotonically</span></div><div><s=
pan style=3D"font-family: 'Microsoft YaHei UI', Tahoma; line-height: norma=
l; font-size: 10.5pt; background-color: transparent;">increasing of the CS=
N in the case&nbsp;</span><span style=3D"font-size: 10.5pt; font-family: '=
Microsoft YaHei UI', Tahoma; line-height: normal; background-color: transp=
arent;">of an instance restart/crash etc"</span><span style=3D"font-size: =
10.5pt; line-height: 1.5; background-color: transparent;">&nbsp;</span><sp=
an style=3D"font-size: 10.5pt; line-height: 1.5; background-color: transpa=
rent;">so I try to</span></div><div><span style=3D"font-size: 10.5pt; line=
-height: 1.5; background-color: transparent;">add wal support for CSN on t=
his patch.</span></div><div><span style=3D"font-size: 10.5pt; line-height:=
 1.5; background-color: transparent;"><br></span></div><div><span style=3D=
"font-size: 10.5pt; line-height: 1.5; background-color: transparent;">That=
's why this thread exist.</span></div><div><br></div><div><div class=3D"pl=
aintext_qoute" style=3D"font-size: 14px; line-height: normal;">&gt; [1] -&=
nbsp;<a href=3D"https://www.postgresql.org/message-id/CA%2Bfd4k4v%2BKdofMy=
N%2BjnOia8-7rto8tsh9Zs3dd7kncvHp12WYw%40mail.gmail.com" style=3D"text-deco=
ration: none !important;">https://www.postgresql.org/message-id/CA%2Bfd4k4=
v%2BKdofMyN%2BjnOia8-7rto8tsh9Zs3dd7kncvHp12WYw%40mail.gmail.com</a></div>=
<div class=3D"plaintext_qoute" style=3D"font-size: 14px; line-height: norm=
al;">&gt; [2] -&nbsp;<a href=3D"https://www.postgresql.org/message-id/2020=
061911294657960322%40highgo.ca" style=3D"text-decoration: none !important;=
" class=3D"">https://www.postgresql.org/message-id/2020061911294657960322%=
40highgo.ca</a></div></div><div><span style=3D"font-family: Verdana, Arial=
, Helvetica, sans-serif; white-space: pre-wrap; text-decoration: underline=
; color: rgb(0, 56, 132);">[3]<a href=3D"https://www.postgresql.org/messag=
e-id/21BC916B-80A1-43BF-8650-3363CCDAE09C%40postgrespro.ru" target=3D"_bla=
nk" style=3D"font-family: Verdana, Arial, Helvetica, sans-serif; white-spa=
ce: pre-wrap; text-decoration: none !important;">https://www.postgresql.or=
g/message-id/21BC916B-80A1-43BF-8650-3363CCDAE09C%40postgrespro.ru</a></sp=
an><span style=3D"font-family: Verdana, Arial, Helvetica, sans-serif; whit=
e-space: pre-wrap;">&nbsp;</span></div><hr style=3D"width: 210px; height: =
1px;" color=3D"#b5c4df" size=3D"1" align=3D"left">=0A<div><span><div style=
=3D"MARGIN: 10px; FONT-FAMILY: verdana; FONT-SIZE: 10pt"><span style=3D"co=
lor: rgb(13, 10, 11); font-family: monospace, monospace; font-size: 10.733=
3px; font-variant-ligatures: normal; orphans: 2; white-space: pre-wrap; wi=
dows: 2;">Regards,</span></div><div style=3D"MARGIN: 10px; FONT-FAMILY: ve=
rdana; FONT-SIZE: 10pt"><span style=3D"color: rgb(13, 10, 11); font-family=
: monospace, monospace; font-size: 10.7333px; font-variant-ligatures: norm=
al; orphans: 2; white-space: pre-wrap; widows: 2;">Highgo Software (Canada=
/China/Pakistan) </span><br style=3D"box-sizing: border-box; color: rgb(13=
, 10, 11); font-family: monospace, monospace; font-size: 10.7333px; font-v=
ariant-ligatures: normal; orphans: 2; white-space: pre-wrap; widows: 2;"><=
span style=3D"color: rgb(13, 10, 11); font-family: monospace, monospace; f=
ont-size: 10.7333px; font-variant-ligatures: normal; orphans: 2; white-spa=
ce: pre-wrap; widows: 2;">URL : </span><a href=3D"http://www.highgo.ca/" r=
el=3D"nofollow" style=3D"box-sizing: border-box; color: rgb(132, 0, 50); t=
ext-decoration: none; font-weight: 600; transition: color 0.2s ease-in-out=
 0s; font-family: monospace, monospace; font-size: 10.7333px; font-variant=
-ligatures: normal; orphans: 2; white-space: pre-wrap; widows: 2;">www.hig=
hgo.ca</a><span style=3D"color: rgb(13, 10, 11); font-family: monospace, m=
onospace; font-size: 10.7333px; font-variant-ligatures: normal; orphans: 2=
; white-space: pre-wrap; widows: 2;"> </span><br style=3D"box-sizing: bord=
er-box; color: rgb(13, 10, 11); font-family: monospace, monospace; font-si=
ze: 10.7333px; font-variant-ligatures: normal; orphans: 2; white-space: pr=
e-wrap; widows: 2;"><span style=3D"color: rgb(13, 10, 11); font-family: mo=
nospace, monospace; font-size: 10.7333px; font-variant-ligatures: normal; =
orphans: 2; white-space: pre-wrap; widows: 2;">EMAIL: mailto:movead(dot)li=
(at)highgo(dot)ca</span></div></span></div><blockquote style=3D"margin-Top=
: 0px; margin-Bottom: 0px; margin-Left: 0.5em; margin-Right: inherit"><div=
>=0A</div></blockquote>=0A</body></html>
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