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Date: Tue, 01 Sep 2020 13:36:38 +0300
From: Alexey Kondratov <a.kondratov@postgrespro.ru>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Michael Paquier <michael@paquier.xyz>, Masahiko Sawada
 <masahiko.sawada@2ndquadrant.com>, Steve Singer <steve@ssinger.info>,
 pgsql-hackers@lists.postgresql.org, Alvaro Herrera
 <alvherre@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Alexander
 Korotkov <a.korotkov@postgrespro.ru>, Masahiko Sawada
 <sawada.mshk@gmail.com>, Jose Luis Tallon <jltallon@adv-solutions.net>
Subject: Re: Allow CLUSTER, VACUUM FULL and REINDEX to change tablespace on
 the fly
In-Reply-To: <20200901101219.GB5450@telsasoft.com>
References: <a0fd6af4bdf3cd209a69cea112ab10ea@postgrespro.ru>
 <20200406184406.GF2228@telsasoft.com>
 <9b6a6cec134451550b74aa2ffd1446d0@postgrespro.ru>
 <20200407204406.GR2228@telsasoft.com> <20200412013352.GA2491@telsasoft.com>
 <20200426175614.GT28974@telsasoft.com> <20200809110252.GD17986@paquier.xyz>
 <20200810022443.GI20473@telsasoft.com> <20200811053945.GG17986@paquier.xyz>
 <20200811070922.GP20473@telsasoft.com> <20200901101219.GB5450@telsasoft.com>
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On 2020-09-01 13:12, Justin Pryzby wrote:
> This patch seems to be missing a call to RelationAssumeNewRelfilenode() 
> in
> reindex_index().
> 
> That's maybe the related to the cause of the crashes I pointed out 
> earlier this
> year.
> 
> Alexey's v4 patch changed RelationSetNewRelfilenode() to accept a 
> tablespace
> parameter, but Michael seemed to object to that.  However that seems 
> cleaner
> and ~30 line shorter.
> 
> Michael, would you comment on that ?  The v4 patch and your comments 
> are here.
> https://www.postgresql.org/message-id/attachment/105574/v4-0001-Allow-REINDEX-and-REINDEX-CONCURRENTLY-to-change-tablespace.patch
> https://www.postgresql.org/message-id/20191127035416.GG5435%40paquier.xyz
> 

Actually, the last time we discussed this point I only got the gut 
feeling that this is a subtle place and it is very easy to break things 
with these changes. However, it isn't clear for me how exactly. That 
way, I'd be glad if Michael could reword his explanation, so it'd more 
clear for me as well.

BTW, I've started doing a review of the last patch set yesterday and 
will try to post some comments later.


Regards
-- 
Alexey Kondratov

Postgres Professional https://www.postgrespro.com
Russian Postgres Company