Re: PostgreSQL 16 release announcement draft

On 8/24/23 11:19 AM, Alvaro Herrera wrote:
> On 2023-Aug-24, Jonathan S. Katz wrote:
>
>> ### Performance Improvements
>>
>> PostgreSQL 16 improves the performance of existing PostgreSQL functionality
>> through new query planner optimizations. In this latest release, the query
>> planner can parallelize `FULL` and `RIGHT` joins, generate better optimized
>> plans for queries that use aggregate functions (e.g. `count`) with a `DISTINCT`
>> or `ORDER BY` clause, utilize incremental sorts for `SELECT DISTINCT` queries,
>> and optimize window function executions so they execute more efficiently.
>
> "optimize window function executions so that they execute blah" sounds
> redundant and strange. Maybe just "optimize execution of window
> functions" is sufficient? Also, using "e.g." there looks somewhat out
> of place; maybe "(such as `count`)" is a good replacement?
>
>> It also introduces `RIGHT` and `OUTER` "anti-joins", which enable users to
>> identify rows not present in a joined table.
>
> Wait. Are you saying we didn't have those already? Looking at
> release-16.sgml I think this refers to commit 16dc2703c541, which means
> this made them more efficient rather than invented them.
>
>
>> This release includes improvements for bulk loading using `COPY` in both single
>> and concurrent operations, with tests showing up to a 300% performance
>> improvement in some cases. PostgreSQL adds support for load balancing in clients
>
> PostgreSQL 16
>
>> that use `libpq`, and improvements to vacuum strategy that reduce the necessity
>> of full-table freezes. Additionally, PostgreSQL 16 introduces CPU acceleration
>> using `SIMD` in both x86 and ARM architectures, resulting in performance gains
>> when processing ASCII and JSON strings, and performing array and subtransaction
>> searches.
>>
>> ### Logical replication
>>
>> Logical replication lets PostgreSQL users stream data to other PostgreSQL
>
> "L.R. in PostgreSQL lets users"?
>
>> instances or subscribers that can interpret the PostgreSQL logical replication
>> protocol. In PostgreSQL 16, users can perform logical decoding from a standby
>
> s/decoding/replication/ ? (It seems odd to use "decoding" when the
> previous sentence used "replication")
>
>> instance, meaning a standby can publish logical changes to other servers. This
>> provides developers with new workload distribution options – for example, using
>> a standby rather than the busier primary to logically replicate changes to
>> downstream systems.
>>
>> Additionally, there are several performance improvements in PostgreSQL 16 to
>> logical replication. Subscribers can now apply large transactions using parallel
>> workers. For tables that do not have a `PRIMARY KEY`, subscribers can use B-tree
>
> "a primary key", no caps.
>
>> indexes instead of sequential scans to find rows. Under certain conditions,
>> users can also speed up initial table synchronization using the binary format.
>>
>> There are several access control improvements to logical replication in
>> PostgreSQL 16, including the new predefined role pg_create_subscription, which
>> grants users the ability to create a new logical subscription. Finally, this
>> release begins adding support for bidirectional logical replication, introducing
>> functionality to replicate data between two tables from different publishers.
>
> "to create a new logical subscription" -> "to create new logical subscriptions"
>
>> ### Developer Experience
>>
>> PostgreSQL 16 adds more syntax from the SQL/JSON standard, including
>> constructors and predicates such as `JSON_ARRAY()`, `JSON_ARRAYAGG()`, and
>> `IS JSON`. This release also introduces the ability to use underscores for
>> thousands separators (e.g. `5_432_000`) and non-decimal integer literals, such
>> as `0x1538`, `0o12470`, and `0b1010100111000`.
>>
>> Developers using PostgreSQL 16 will also benefit from the addition of multiple
>> commands to `psql` client protocol, including the `\bind` command, which allows
>> users to execute parameterized queries (e.g `SELECT $1 + $2`) then use `\bind`
>> to substitute the variables.
>
> This paragraph sounds a bit suspicious. What do you mean with "multiple
> commands to psql client protocol"? Also, I think "to execute parameterized
> queries" should be "to prepare parameterized queries", and later "then
> use \bind to execute the query substituting the variables".
>
>
>
>> ### Monitoring
>>
>> A key aspect of tuning the performance of database workloads is understanding
>> the impact of your I/O operations on your system. PostgreSQL 16 helps simplify
>> how you can analyze this data with the new pg_stat_io view, which tracks key I/O
>> statistics such as shared_buffer hits and I/O latency.
>
> Hmm, I think what pg_stat_io gives you is data which wasn't available
> previously at all. Maybe do something like "Pg 16 introduces
> pg_stat_io, a new source of key I/O metrics that can be used for more
> fine grained something something".
>
>> Additionally, this release adds a new field to the `pg_stat_all_tables` view
>> that records a timestamp representing when a table or index was last scanned.
>> PostgreSQL also makes auto_explain more readable by logging values passed into
>
> PostgreSQL 16
>
>> parameterized statements, and improves accuracy of pg_stat_activity's
>> normalization algorithm.
>
> I think jian already mentioned that this refers to pg_stat_statement
> query fingerprinting. I know that the query_id also appears in
> pg_stat_activity, but that is much newer, and it's not permanent there
> like in pss. Maybe it should be "of the query fingerprinting algorithm
> used by pg_stat_statement and pg_stat_activity".
>
>> ## Images and Logos
>>
>> Postgres, PostgreSQL, and the Elephant Logo (Slonik) are all registered
>> trademarks of the [PostgreSQL Community Association of Canada](https://www.postgres.ca).
>
> Isn't this just the "PostgreSQL Community Association", no Canada?

Thanks for the feedback. I accepted most of the changes. Please see
revised text here, which also includes the URL substitutions.

Jonathan