Re: WAL usage calculation patch - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: WAL usage calculation patch
Date
Msg-id CAA4eK1LjkwGOegWMfs3tggD3-BXLzyZXFz7qBZaf_yLBPjZdHQ@mail.gmail.com
Whole thread Raw
In response to Re: WAL usage calculation patch  (Dilip Kumar <dilipbalaut@gmail.com>)
Responses Re: WAL usage calculation patch  (Dilip Kumar <dilipbalaut@gmail.com>)
List pgsql-hackers
On Fri, Apr 3, 2020 at 8:55 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> I think now I got the reason.  Basically, both of these records are
> storing the FPW, and FPW size can vary based on the hole size on the
> page.  If hold size is smaller the image length will be more, the
> image_len= BLCKSZ-hole_size.  So in subsequent records, the image size
> is bigger.
>

This means if we always re-create the database or may be keep
full_page_writes to off, then we should get consistent WAL usage data
for all tests.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com



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