John Spray b8095f84a0 pageserver: make true GC cutoff visible in admin API, rebrand latest_gc_cutoff as applied_gc_cutoff (#10707) ...

## Problem

We expose `latest_gc_cutoff` in our API, and callers understandably were
using that to validate LSNs for branch creation. However, this is _not_
the true GC cutoff from a user's point of view: it's just the point at
which we last actually did GC. The actual cutoff used when validating
branch creations and page_service reads is the min() of latest_gc_cutoff
and the planned GC lsn in GcInfo.

Closes: https://github.com/neondatabase/neon/issues/10639

## Summary of changes

- Expose the more useful min() of GC cutoffs as `gc_cutoff_lsn` in the
API, so that the most obviously named field is really the one people
should use.
- Retain the ability to read the LSN at which GC was actually done, in
an `applied_gc_cutoff_lsn` field.
- Internally rename `latest_gc_cutoff_lsn` to `applied_gc_cutoff_lsn`
("latest" was a confusing name, as the value in GcInfo is more up to
date in terms of what a user experiences)
- Temporarily preserve the old `latest_gc_cutoff_lsn` field for compat
with control plane until we update it to use the new field.

---------

Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>

2025-02-13 10:33:47 +00:00

..

src

pageserver: make true GC cutoff visible in admin API, rebrand latest_gc_cutoff as applied_gc_cutoff (#10707)

2025-02-13 10:33:47 +00:00

Cargo.toml

fast imports: initial Importer and Storage changes (#9218)

2024-11-22 22:47:06 +00:00