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This makes it possible for the compiler to validate that a match block matched all PostgreSQL versions we support. ## Problem We did not have a complete picture about which places we had to test against PG versions, and what format these versions were: The full PG version ID format (Major/minor/bugfix `MMmmbb`) as transfered in protocol messages, or only the Major release version (`MM`). This meant type confusion was rampant. With this change, it becomes easier to develop new version-dependent features, by making type and niche confusion impossible. ## Summary of changes Every use of `pg_version` is now typed as either `PgVersionId` (u32, valued in decimal `MMmmbb`) or PgMajorVersion (an enum, with a value for every major version we support, serialized and stored like a u32 with the value of that major version) --------- Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>
This module contains utilities for working with PostgreSQL file formats. It's a collection of structs that are auto-generated from the PostgreSQL header files using bindgen, and Rust functions to read and manipulate them.
There are also a bunch of constants in pg_constants.rs that are copied
from various PostgreSQL headers, rather than auto-generated. They mostly
should be auto-generated too, but that's a TODO.
The PostgreSQL on-disk file format is not portable across different
CPU architectures and operating systems. It is also subject to change
in each major PostgreSQL version. Currently, this module supports
PostgreSQL v14, v15 and v16: bindings and code that depends on them are
version-specific.
This code is organized in modules postgres_ffi::v14, postgres_ffi::v15 and
postgres_ffi::v16. Version independent code is explicitly exported into
shared postgres_ffi.
TODO: Currently, there is also some code that deals with WAL records in pageserver/src/waldecoder.rs. That should be moved into this module. The rest of the codebase should not have intimate knowledge of PostgreSQL file formats or WAL layout, that knowledge should be encapsulated in this module.