Re: Add a GUC check hook to ensure summarize_wal cannot be enabled when wal_level is minimal

On 2024/07/17 22:44, Robert Haas wrote:
> On Tue, Jul 16, 2024 at 1:16 PM Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>> I don't have another solution that can be pushed into v17. I understand
>> the risks raised so far, so I'm okay with just pushing the "fast_forward" patch.
>> It might be helpful to add a note to the summarize_wal documentation,
>> for example, "summarize_wal can be enabled after startup with wal_level = minimal,
>> but WAL generated at this level won't be summarized."?
> 
> Here is v5. This version differs from v4 in that it updates the
> documentation for summarize_wal and pg_get_wal_summarizer_state(). The
> previous version made no documentation changes.

Thanks for updating the patch! It looks good to me, except for one minor detail.

> +        reaches WAL not generated under <literal>wal_level=minimal</literal>,
> +        it will resume writing summaries to disk.

"WAL not generated under wal_level=minimal" sounds a bit confusing??
How about "WAL generated while wal_level is replica or higher" instead?

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION