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From: Nathan Bossart <[email protected]>
To: Jeff Davis <[email protected]>
Cc: Bharath Rupireddy <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: Dilip Kumar <[email protected]>
Cc: Kyotaro Horiguchi <[email protected]>
Cc: [email protected]
Cc: Masahiko Sawada <[email protected]>
Subject: Re: Improve WALRead() to suck data directly from WAL buffers when possible
Date: Tue, 24 Oct 2023 20:54:01 -0500
Message-ID: <20231025015401.GB977906@nathanxps13> (raw)
In-Reply-To: <[email protected]>
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	<[email protected]>

On Tue, Oct 24, 2023 at 05:15:19PM -0700, Jeff Davis wrote:
> * Are you sure that reducing the number of calls to memcpy() is a win?
> I would expect that to be true only if the memcpy()s are tiny, but here
> they are around XLOG_BLCKSZ. I believe this was done based on a comment
> from Nathan Bossart, but I didn't really follow why that's important.
> Also, if we try to use one memcpy for all of the data, it might not
> interact well with my idea above to avoid taking the lock.

I don't recall exactly why I suggested this, but if additional memcpy()s
help in some way and don't negatively impact performance, then I retract my
previous comment.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

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