78c5e141e9
This commit introduces the uuidv7() SQL function, which generates UUID version 7 as specified in RFC 9652. UUIDv7 combines a Unix timestamp in milliseconds and random bits, offering both uniqueness and sortability. In our implementation, the 12-bit sub-millisecond timestamp fraction is stored immediately after the timestamp, in the space referred to as "rand_a" in the RFC. This ensures additional monotonicity within a millisecond. The rand_a bits also function as a counter. We select a sub-millisecond timestamp so that it monotonically increases for generated UUIDs within the same backend, even when the system clock goes backward or when generating UUIDs at very high frequency. Therefore, the monotonicity of generated UUIDs is ensured within the same backend. This commit also expands the uuid_extract_timestamp() function to support UUID version 7. Additionally, an alias uuidv4() is added for the existing gen_random_uuid() SQL function to maintain consistency. Bump catalog version. Author: Andrey Borodin Reviewed-by: Sergey Prokhorenko, Przemysław Sztoch, Nikolay Samokhvalov Reviewed-by: Peter Eisentraut, Jelte Fennema-Nio, Aleksander Alekseev Reviewed-by: Masahiko Sawada, Lukas Fittl, Michael Paquier, Japin Li Reviewed-by: Marcos Pegoraro, Junwang Zhao, Stepan Neretin Reviewed-by: Daniel Vérité Discussion: https://postgr.es/m/CAAhFRxitJv%3DyoGnXUgeLB_O%2BM7J2BJAmb5jqAT9gZ3bij3uLDA%40mail.gmail.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.