Re: Fix checkpoint skip logic on idle systems by tracking LSN progress

Hi,

On 2016-12-21 13:28:54 -0800, Andres Freund wrote:
> A mime-type of invalid/octet-stream? That's an, uh, odd choice.
>
> Working on committing this (tomorrow morning, not tonight). There's
> some relatively minor things I want to change:
>
> - I don't like the name XLogSetFlags() - it's completely unclear what
> that those flags refer to - it could just as well be replay
> related. XLogSetRecordFlags()?
> - Similarly I don't like the name "progress LSN" much. What does
> "progress" really mean in that". Maybe "consistency LSN"?
> - It's currently required to avoid triggering archive timeouts and
> checkpoints triggering each other, but I'm nervous marking all xlog
> switches as unimportant. I think it'd be better to only mark timeout
> triggered switches as such.

Here's an updated version of this. Besides the above (with "consistency
LSN" now named "lastImportantAt" instead of the previous
lastProgressAt), I changed how the skipping works in the bgwriter: I
don't see any need to involve the checkpoint location there. This also
allows to drop GetLastCheckpointPtr(). Besides that I did a fair amount
of comment-smithing.

I plan to commit this later today. Hope I got the reviewers roughly right.

Regards,

Andres