Re: PostgreSQL 17 release announcement draft - Mailing list pgsql-advocacy

From Andrew Atkinson
Subject Re: PostgreSQL 17 release announcement draft
Date
Msg-id CAG6XLEk19rgUWarFbO2uq55gkvwRPMYEFXrWKgM5zyp8BACgZg@mail.gmail.com
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In response to Re: PostgreSQL 17 release announcement draft  (Andrew Atkinson <andyatkinson@gmail.com>)
List pgsql-advocacy
I'll send one more bigger email. I also have made these as comments in a google doc I'm happy to add anyone to if they're interested. Let me know.

> PostgreSQL 17 extends its performance gains to query execution. Planner statistics help PostgreSQL to determine the best way to search for data, and PostgreSQL 17 can now use planner statistics and the sort order [common table expressions](https://www.postgresql.org/docs/17/queries-with.html) ([`WITH` queries](https://www.postgresql.org/docs/17/queries-with.html)) to further speed up queries.

Was that meant to be the sort order "from" CTEs? Maybe a missing "From"?


to support more expressive JSON processing capabilities and implementation of the SQL/JSON standard. 

Was that meant to be something like "and to expand the implementation" of or "an expanded implementation"?


> "with an emphasis of converting JSON data to a native PostgreSQL data type"

Was that meant to be an emphasis "on" and not "of" ?

> For the merge section, here's a proposed reworked version:

PostgreSQL 17 provides expanded control over `MERGE` behavior, including a new `merge_action` function that describes how a row was modified.

PostgreSQL 17 provides new capabilities and performance improvements for bulk data loading and exporting. This includes improving exports of large rows by up to 2x using the [`COPY`](https://www.postgresql.org/docs/17/sql-copy.html) command, and performance improvements for cases when the source and destination encodings match. A new option `ON_ERROR` was added which can be used to allow imports to continue even when errors happen for inserts.

> For the predefined role, something to consider would be using action verbs. I don't know if this seems too inconsistent though. It makes it easier to write. For example:

Use the new `pg_maintain` [predefined role](https://www.postgresql.org/docs/17/predefined-roles.html) to grant permissions for maintenance operations.


> For the EXPLAIN enhancements:

PostgreSQL 17 [`EXPLAIN`](https://www.postgresql.org/docs/17/sql-explain.html) now shows the time spent for I/O block reads and writes, and includes two new options: `SERIALIZE` and `MEMORY`, useful for seeing the time spent in data conversion for network transmission, and how much memory was used.



That's all I've got.

This is an exciting release! Nice work!





On Thu, Sep 5, 2024 at 1:44 PM Andrew Atkinson <andyatkinson@gmail.com> wrote:
Additional chunk:

Proposed:
PostgreSQL 17 improves the performance of queries with `IN` clauses that use [B-tree](https://www.postgresql.org/docs/17/indexes-types.html#INDEXES-TYPES-BTREE) indexes, the default index method in PostgreSQL). Support for parallel index builds were added for [BRIN](https://www.postgresql.org/docs/17/brin.html) indexing.

PostgreSQL 17 leverages the constraints you've defined. The query planner removes redundant `IS NOT NULL` statements when a column has a `NOT NULL` constraint, and skips over `IS NULL` clauses for columns with an `IS NOT NULL` constraint.


On Thu, Sep 5, 2024 at 11:58 AM Andrew Atkinson <andyatkinson@gmail.com> wrote:

On Thu, Sep 5, 2024 at 11:49 AM Andrew Atkinson <andyatkinson@gmail.com> wrote:
Hi Jonathan. Do you want change proposals here as text snippets in emails? It seems the patch process isn't used here.

If so, here's an attempted reduction that echoes what Robert said. I also thought explaining Vacuum wouldn't be necessary for this audience, so less lead-in could work. Is the benefit to end users that there is less memory and CPU needed by vacuum, thus more CPU and memory is available to their foreground workload?

Original:
> A foundational feature of PostgreSQL is [vacuum](https://www.postgresql.org/docs/17/routine-vacuuming.html), which is used to reclaim storage from data that was marked as removed. Reducing resources required for vacuuming directly helps other areas of PostgreSQL, particularly on very busy systems. PostgreSQL 17 introduces a new internal memory structure for vacuum that's shown up to a 20x reduction in memory and improvements in overall vacuuming speed.

Proposed:
The PostgreSQL [vacuum](https://www.postgresql.org/docs/17/routine-vacuuming.html) process is critical for healthy operations, requiring server instance resources to operate. With PostgreSQL 17, a new internal memory structure for vacuum was used that consumes up to 20x less memory. This improves vacuum speed and also reduces the use of shared resources, making more available for your workload.


Something along those lines, where the benefit to the user is they could expect more CPU/mem etc. available for their SQL operations, right?  This could be something folks want to benchmark as well as a reason to upgrade, at least for Vacuum-intensive workloads, high UPDATE and DELETE operations etc.





On Thu, Sep 5, 2024 at 11:04 AM Robert Haas <robertmhaas@gmail.com> wrote:
On Thu, Sep 5, 2024 at 5:22 AM Peter Eisentraut <peter@eisentraut.org> wrote:
> On 04.09.24 23:05, Jonathan S. Katz wrote:
> > Attached is the draft of the PostgreSQL 17 release announcement. This is
> > a draft of the text that will go into the press kit, with the key
> > portions to review starting from the top of the document, up until the
> > "About PostgreSQL" section.
>
> I noticed that we don't yet have a list of major features in the PG17
> release notes.  We should probably put that in soon, so that what we
> list there and what is in the announcement are consistent.

+1.

> On the actual list, there will be lots of opinions to be had, but I'll
> just offer one:  I don't think the MERGE RETURNING clause deserves twice
> as much space as incremental backup.

I agree with that, although obviously I'm biased.

I also feel like this whole thing could just be shorter. If it were
half as long and mentioned fewer things and those more briefly, would
we be worse off? I think we might be better off, because it just feels
wordy to me right now. For example:

A foundational feature of PostgreSQL is
[vacuum](https://www.postgresql.org/docs/17/routine-vacuuming.html),
which is used to reclaim storage from data that was marked as removed.
Reducing resources required for vacuuming directly helps other areas
of PostgreSQL, particularly on very busy systems. PostgreSQL 17
introduces a new internal memory structure for vacuum that's shown up
to a 20x reduction in memory and improvements in overall vacuuming
speed. This release also removes the  `1GB` limit on the memory it can
use (controlled by
[`maintenance_work_mem`](https://www.postgresql.org/docs/17/runtime-config-resource.html#GUC-MAINTENANCE-WORK-MEM)),
letting users apply more resources to vacuuming, which is beneficial
for systems with lots of changes.

It seems to me that the first two sentences could just be completely
nuked, and everything from "letting users" to the end could also be
nuked. At least to me, all of that stuff reads as unnecessarily
filler. I'm not at all sure that removing the 1GB limit on
maintenance_work_mem is important enough that it needs to be in the
release announcement -- I agree it's a good improvement, but to have
it be one of the first things in the press release seems like an odd
choice from my perspective. Nobody's going to look back on this
release years from now and say "oh, that was the release where could
finally set maintenance_work_mem=4GB, that was so much better". If
they think about VACUUM, they'll think about the 20x memory reduction
stuff which made the ability to configure values larger than 1GB
irrelevant in the first place. So I'd probably delete the part about
lifting the 1GB cap entirely. But even if you don't do that, the
paragraph could be half as long without losing anything, from my
perspective.

--
Robert Haas
EDB: http://www.enterprisedb.com


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