Re: PostgreSQL 15 release announcement draft

On 9/12/22 4:17 PM, David Rowley wrote:
> On Tue, 13 Sept 2022 at 04:53, Jonathan S. Katz <jkatz@postgresql.org> wrote:
>> Here is a (penultimate?) draft that includes URLs. Please provide any
>> additional feedback no later than 2022-09-14 0:00 AoE. After that, we
>> will begin the translation process.
> 
> Thanks for drafting these up.
> 
> I noticed a couple of things, one pretty minor and one that might need
> a bit of a reword.
> 
>> sorted. Using `row_number()`, `rank()`, and `count()` as
> 
> dense_rank() is affected by that change too. Maybe it was just omitted
> for brevity. I'm ok if it was, but just wanted to make sure it wasn't
> an accidental omission.

It would be an accidental omission. It's also omitted from the release 
notes:

"Improve the performance of window functions that use row_number(), 
rank(), and count() (David Rowley)"[1]

so we should add it there too :)

>> certain operating systems, PostgreSQL 15 supports the ability to
>> [prefetch WAL file contents](https://www.postgresql.org/docs/15/runtime-config-wal.html#GUC-RECOVERY-PREFETCH)
> 
> I think "ability to prefetch WAL file contents" is not really an
> accurate way to describe this feature.  What the prefetcher does is
> prefetch the pages of tables, indexes and materialized views which are
> referenced by WAL, so that when the recovery process comes along
> later, the pages of these relations which are being changed by the WAL
> record are more likely to be in memory so that the recovery process is
> less likely to have to load the referenced pages from disk.

Thanks. That's a really crisp explanation :)

> Perhaps the text should read:
> 
> "PostgreSQL 15 adds support for prefetching pages referenced in [WAL]."

What do you think of this (copied from the attached file)

On certain operating systems, PostgreSQL 15 adds support to [prefetch 
pages referenced in 
WAL](https://www.postgresql.org/docs/15/runtime-config-wal.html#GUC-RECOVERY-PREFETCH) 
to help speed up recovery times.

Thanks,

Jonathan

[1] https://www.postgresql.org/docs/15/release-15.html