Hi, Attached is a draft of the PG12 Beta 1 press release that is going out this Thursday. The primary goals of this release announcement are to introduce new features, enhancements, and changes that are available in PG12, as well as encourage our users to test and provide feedback to help ensure the stability of the release.
Speaking of feedback, please provide me with your feedback on the technical correctness of this announcement so I can incorporate changes prior to the release. Thanks! Jonathan
PostgreSQL 12 Beta 1 Released ============================= The PostgreSQL Global Development Group announces that the first beta release of PostgreSQL 12 is now available for download. This release contains previews of all features that will be available in the final release of PostgreSQL 12, though some details of the release could change before then. In the spirit of the open source PostgreSQL community, we strongly encourage you to test the new features of PostgreSQL 12 in your database systems to help us eliminate any bugs or other issues that may exist. While we do not advise for you to run PostgreSQL 12 Beta 1 in your production environments, we encourage you to find ways to run your typical application workloads against this beta release. Your testing and feedback will help the community ensure that the PostgreSQL 12 release upholds our standards of providing a stable, reliable release of the world's most advanced open source relational database. PostgreSQL 12 Features Highlights --------------------------------- ### Indexing Performance, Functionality, and Management PostgreSQL 12 improves the overall performance of the standard B-tree indexes with improvements to the overall space management of these indexes as well. These improvements also provide an overall reduction of bloating when using B-tree for specific use cases, in addition to a performance gain. Additionally, PostgreSQL 12 adds the ability to rebuild indexes concurrently, which lets you perform a [`REINDEX`](https://www.postgresql.org/docs/devel/sql-reindex.html) operation without blocking any writes to the index. The inclusion of this feature should help with length index rebuilds that could cause potential downtime evens when administration a PostgreSQL database in a production environment. PostgreSQL 12 extends the abilities of several of the specialized indexing mechanisms. The ability to create covering indexes, i.e. the `INCLUDE` clause that was introduced in PostgreSQL 11, have now been added to GiST indexes. SP-GiST indexes now support the ability to perform K-nearest neighbor (K-NN) queries for data types that support the distance (`<->`) operation. The amount of write-ahead log (WAL) overhead generated when creating a GiST, GIN, or SP-GiST index is also significantly reduced in PostgreSQL 12, which provides several benefits to the overall disk utilization of a PostgreSQL cluster as well as using features such as continuous archiving and streaming replication. ### Inlined WITH queries (Common table expressions) Common table expressions (aka `WITH` queries) can now be automatically inlined in a query if they are a) not recursive, b) do not have any side-effects and c) are only referenced once in a later part of a query. These removes a known "optimization fence" that has existed since the introduction of the `WITH` clause in PostgreSQL 8.4 You can force a `WITH` query to be inlined using the `NOT MATERIALIZED` clause, e.g. ``` WITH c AS NOT MATERIALIZED ( SELECT * FROM a WHERE a.x % 4 ) SELECT * FROM c JOIN d ON d.y = a.x; ``` ### Partitioning PostgreSQL 12 improves on the performance of processing tables with thousands of partitions for operations that only need to use a small number of partitions. PostgreSQL 12 also provides improvements to the performance of both using `COPY` with a partitioned table as well as the `ATTACH PARTITION` operation. Additionally, the ability to use foreign keys to reference partitioned tables is now allowed in PostgreSQL 12. ### JSON path queries per SQL/JSON specification PostgreSQL 12 now lets you execute [JSON path queries](https://www.postgresql.org/docs/devel/functions-json.html#FUNCTIONS-SQLJSON-PATH) per the SQL/JSON specification in the SQL:2016 standard. Similar to XPath expressions for XML, JSON path expressions let you evaluate a variety of arithmetic expressions and functions in addition to comparing values within JSON documents. A subset of these expressions can be accelerated with GIN indexes, letting you execute highly performant lookups across sets of JSON data. ### Collations PostgreSQL 12 now supports case-insensitive and accent-insensitive collations for ICU provided collations, also known as "[nondeterministic collations](https://www.postgresql.org/docs/devel/collation.html#COLLATION-NONDETERMINISTIC)". When used, these collations can provide convenience for comparisons and sorts, but can also lead to a performance penalty depending as a collation may need to make additional checks on a string. ### Most-common Value Statistics [`CREATE STATISTICS`](https://www.postgresql.org/docs/devel/sql-createstatistics.html), introduced in PostgreSQL 10 to help collect more complex statistics to improve query planning, now supports most-common value statistics. This leads to improved query plans for distributions that are non-uniform. ### Generated Columns PostgreSQL 12 lets you create [generated columns](https://www.postgresql.org/docs/devel/ddl-generated-columns.html) that compute their values based on the contents of other columns. This feature provides two types of generated columns: - Stored generated columns, which are computed on inserts and updated and are saved on disk - Virtual generated columns, which are computed only when a column is read as part of a query ### Pluggable Table Storage Interface PostgreSQL 12 introduces the pluggable table storage interface that allows for the creation and use of different storage mechanisms for table storage. New access methods can be added to a PostgreSQL cluster using the [`CREATE ACCESS METHOD`](https://www.postgresql.org/docs/devel/sql-create-access-method.html) and subsequently added to tables with the new `USING` clause on `CREATE TABLE`. A table storage interface can be defined by creating a new [table access method](https://www.postgresql.org/docs/devel/tableam.html). In PostgreSQL 12, the storage interface that is used by default is the `heap` access method, which is currently the only supported method. ### Page Checksums The `pg_verify_checkums` command has been renamed to [`pg_checksums`](https://www.postgresql.org/docs/devel/app-pgchecksums.html) and now supports the ability to enable and disable page checksums across an PostgreSQL cluster that is offline. Previously, page checksums could only be enabled during the initialization of a cluster with `initdb`. ### Authentication GSSAPI now supports client and server-side encryption and can be specified in the [`pg_hba.conf`](https://www.postgresql.org/docs/devel/auth-pg-hba-conf.html) file using the `hostgssenc` and `hostnogssenc` record types. PostgreSQL 12 also allows for LDAP servers to be discovered based on `DNS SRV` records if PostgreSQL was compiled with OpenLDAP. Noted Behavior Changes ---------------------- There are several changes introduced in PostgreSQL 12 that can affect the behavior as well as management of your ongoing operations. A few of these are noted below; for information about other changes, please review the "Migrating to Version 12" section of the [release notes](https://www.postgresql.org/docs/devel/release-12.html). 1. The `recovery.conf` configuration file is now merged into the main `postgresql.conf` file. PostgreSQL will not start if it detects that `recovery.conf` is present. To put PostgreSQL into a non-primary mode, you can use the `recovery.signal` and the `standby.signal` files. You can read more about [archive recovery](https://www.postgresql.org/docs/devel/runtime-config-wal.html#RUNTIME-CONFIG-WAL-ARCHIVE-RECOVERY) here: https://www.postgresql.org/docs/devel/runtime-config-wal.html#RUNTIME-CONFIG-WAL-ARCHIVE-RECOVERY 2. Just-in-Time (JIT) compilation is now enabled by default. Additional Features ------------------- Many other new features and improvements have been added to PostgreSQL 12, some of which may be as or more important to specific users than what is mentioned above. Please see the [Release Notes](https://www.postgresql.org/docs/devel/release-12.html) for a complete list of new and changed features. Testing for Bugs & Compatibility -------------------------------- The stability of each PostgreSQL release greatly depends on your, the community, to test the upcoming version with your workloads and testing tools in order to find bugs and regressions before the release of PostgreSQL 12. As this is a Beta, minor changes to database behaviors, feature details, and APIs are still possible. Your feedback and testing will help determine the final tweaks on the new features, so please test in the near future. The quality of user testing helps determine when we can make a final release. A list of [open issues](https://wiki.postgresql.org/wiki/PostgreSQL_12_Open_Items) is publicly available in the PostgreSQL wiki. You can [report bugs](https://www.postgresql.org/account/submitbug/) using this form on the PostgreSQL website: https://www.postgresql.org/account/submitbug/ Beta Schedule ------------- This is the first beta release of version 12. The PostgreSQL Project will release additional betas as required for testing, followed by one or more release candidates, until the final release in late 2019. For further information please see the [Beta Testing](https://www.postgresql.org/developer/beta/) page. Links ----- * [Download](https://www.postgresql.org/download/) * [Beta Testing Information](https://www.postgresql.org/developer/beta/) * [PostgreSQL 12 Beta Release Notes](https://www.postgresql.org/docs/devel/release-12.html) * [PostgreSQL 12 Open Issues](https://wiki.postgresql.org/wiki/PostgreSQL_12_Open_Items) * [Submit a Bug](https://www.postgresql.org/account/submitbug/)
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