Re: Remove secondary checkpoint

From: Simon Riggs <simon(at)2ndquadrant(dot)com>
To: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Remove secondary checkpoint
Date: 2017-10-31 14:00:27
Message-ID: CANP8+jJCrpPR0Kgwp92f1qEJvhBEQkSbdpSCb-Q9W_MU72TQHw@mail.gmail.com
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On 30 October 2017 at 18:58, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> On 30 October 2017 at 15:22, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>
>>> You forgot to update this formula in xlog.c:
>>> distance = (2.0 + CheckPointCompletionTarget) * CheckPointDistanceEstimate;
>>> /* add 10% for good measure. */
>>> distance *= 1.10;
>>> You can guess easily where the mistake is.
>>
>> Doh - fixed that before posting, so I must have sent the wrong patch.
>>
>> It's the 10%, right? ;-)
>
> So, there are 2 locations that mention 2.0 in xlog.c
>
> I had already fixed one, which is why I remembered editing it.
>
> The other one you mention has a detailed comment above it explaining
> why it should be 2.0 rather than 1.0, so I left it.
>
> Let me know if you still think it should be removed? I can see the
> argument both ways.
>
> Or maybe we need another patch to account for manual checkpoints.

Revised patch to implement this

--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Attachment Content-Type Size
remove_secondary_checkpoint.v5.patch application/octet-stream 19.2 KB

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