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Subject: Re: max_slot_wal_keep_size and wal_keep_segments
To: David Steele <david@pgmasters.net>,
 Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: alvherre@2ndquadrant.com, pgsql-hackers@postgresql.org
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From: Fujii Masao <masao.fujii@oss.nttdata.com>
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Date: Fri, 17 Jul 2020 18:11:36 +0900
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On 2020/07/14 20:30, David Steele wrote:
> On 7/14/20 12:00 AM, Fujii Masao wrote:
>>
>> The patch was no longer applied cleanly because of recent commit.
>> So I updated the patch. Attached.
>>
>> Barring any objection, I will commit this patch.
> 
> This doesn't look right:
> 
> +   the <xref linkend="guc-wal-keep-size"/> most recent megabytes
> +   WAL files plus one WAL file are
> 
> How about:
> 
> +   <xref linkend="guc-wal-keep-size"/> megabytes of
> +   WAL files plus one WAL file are

Thanks for the comment! Isn't it better to keep "most recent" part?
If so, what about either of the followings?

1. <xref linkend="guc-wal-keep-size"/> megabytes of WAL files plus
     one WAL file that were most recently generated are kept all time.

2. <xref linkend="guc-wal-keep-size"/> megabytes + <xref linkend="guc-wal-segment-size"> bytes
     of WAL files that were most recently generated are kept all time.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION