Subject: Re: [PATCH] xlogreader: do not read a file block twice
To: Michael Paquier <michael@paquier.xyz>,
 Grigory Smolkin <g.smolkin@postgrespro.ru>
Cc: pgsql-hackers@lists.postgresql.org
References: <2ddf4a32-517e-d6f4-d992-4a63b6035bfd@postgrespro.ru>
 <87e30af6-f85a-dc95-4574-95cded028786@postgrespro.ru>
 <20190212042300.GL1475@paquier.xyz>
From: Arthur Zakirov <a.zakirov@postgrespro.ru>
Message-ID: <1fa0c9fe-32a5-3ebd-e9c2-b5e2c9abc03e@postgrespro.ru>
Date: Tue, 12 Feb 2019 11:44:14 +0300
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On 12.02.2019 07:23, Michael Paquier wrote:
>> On 02/11/2019 07:25 PM, Arthur Zakirov wrote:
>>> Grigory noticed that one of our utilities has very slow performance when
>>> xlogreader reads zlib archives. We found out that xlogreader sometimes
>>> reads a WAL file block twice.
>>>
>>> What do you think?
> 
> I think that such things, even if they look simple, need a careful
> lookup, and I have not looked at the proposal yet.  Could you add it
> to the next commit fest so as we don't lose track of it?
> https://commitfest.postgresql.org/22/

Of course. Agree, it may be a non trivial case. Added as a bug fix:
https://commitfest.postgresql.org/22/1994/

-- 
Arthur Zakirov
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company