From: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Cc: sawada.mshk@gmail.com
Cc: tgl@sss.pgh.pa.us
Cc: alvherre@2ndquadrant.com
Cc: sk@zsrv.org
Cc: nasbyj@amazon.com
Cc: andres@anarazel.de
Cc: robertmhaas@gmail.com
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: pgsql: Improve autovacuum logging for aggressive and anti-wraparound ru
Date: Fri, 29 Mar 2019 09:11:47 -0400
Message-ID: <e454b280-d7b5-1798-b01c-213b663d8907@2ndQuadrant.com> (raw)
In-Reply-To: <20190329115138.GD1954@paquier.xyz>
References: <CAD21AoBR+y31ps+=G6_fxxVd_o1itTnaK19sDAEhAP_RyVT2AA@mail.gmail.com>
<20181005031603.GF1629@paquier.xyz>
<20181005063504.GB14664@paquier.xyz>
<20181009.181536.142257785.horiguchi.kyotaro@lab.ntt.co.jp>
<920b7f84-407c-005c-4b7d-e8266a17d22b@2ndQuadrant.com>
<20190309011537.GD9266@paquier.xyz>
<20190329115138.GD1954@paquier.xyz>
On 3/29/19 7:51 AM, Michael Paquier wrote:
> On Sat, Mar 09, 2019 at 10:15:37AM +0900, Michael Paquier wrote:
>> I am adding an open item about that. I think I could commit the
>> patch, but I need to study it a bit more first.
> So, coming back to this thread, and studying the problem again, it
> looks that the diagnostic that a non-aggressive, anti-wraparound
> vacuum could be triggered because the worker sees trouble in the
> force because of some activity happening in parallel. Hence, if we
> face this case, it looks right to skip the vacuum for this relation.
>
> Attached is an updated patch with a better error message, more
> comments, and the removal of the anti-wraparound non-aggressive log
> which was added in 28a8fa9. The error message could be better I
> guess. Suggestions are welcome.
>
> Thoughts?
+ (errmsg_internal("found vacuum to prevent wraparound of
table \"%s.%s.%s\" to be not aggressive, so skipping",
This might convey something to hackers, but I doubt it will convey much
to regular users. Perhaps something like "skipping redundant
anti-wraparound vacuum of table ..." would be better.
The comment is also a bit too tentative. Perhaps something like this
would do:
Normally the relfrozenxid for an anti-wraparound vacuum will be old
enough to force an aggressive vacuum. However, a concurrent vacuum
might have already done this work that the relfroxzenxid in relcache
has been updated. If that happens this vacuum is redundant, so skip it.
cheers
andrew
--
Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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Cc: andrew.dunstan@2ndquadrant.com, michael@paquier.xyz, horiguchi.kyotaro@lab.ntt.co.jp, sawada.mshk@gmail.com, tgl@sss.pgh.pa.us, alvherre@2ndquadrant.com, sk@zsrv.org, nasbyj@amazon.com, andres@anarazel.de, robertmhaas@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: pgsql: Improve autovacuum logging for aggressive and anti-wraparound ru
In-Reply-To: <e454b280-d7b5-1798-b01c-213b663d8907@2ndQuadrant.com>
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