Re: Online checksums patch - once again

On 10/02/2021 16:25, Magnus Hagander wrote:
> On Tue, Feb 9, 2021 at 9:54 AM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>>
>> (I may have said this before, but) My overall high-level impression of
>> this patch is that it's really cmmplex for a feature that you use maybe
>> once in the lifetime of a cluster. I'm happy to review but I'm not
>> planning to commit this myself. I don't object if some other committer
>> picks this up (Magnus?).
> 
> A fairly large amount of this complexity comes out of the fact that it
> now supports restarting and tracks checksums on a per-table basis. We
> skipped this in the original patch for exactly this reason (that's not
> to say there isn't a fair amount of complexity even without it, but it
> did substantially i increase both the size and the complexity of the
> patch), but in the review of that i was specifically asked for having
> that added. I personally don't think it's worth that complexity but at
> the time that seemed to be a pretty strong argument. So I'm not
> entirely sure how to move forward with that...
> 
> is your impression that it would still be too complicated, even without that?

I'm not sure. It would certainly be a lot better.

Wrt. restartability, I'm also not very happy with the way that works - 
or rather doesn't :-) - in this patch. After shutting down and 
restarting the cluster, you have to manually call 
pg_enable_data_checksums() again to restart the checksumming process.

- Heikki