Christian Schwarz ff51e96fbd fix synthetic size for (last_record_lsn - gc_horizon) < initdb_lsn (#3874) ...

fix synthetic size for (last_record_lsn - gc_horizon) < initdb_lsn

Assume a single-timeline project.
If the gc_horizon covers all WAL (last_record_lsn < gc_horizon)
but we have written more data than just initdb, the synthetic
size calculation worker needs to calculate the logical size
at LSN initdb_lsn (Segment BranchStart).

Before this patch, that calculation would incorrectly return
the initial logical size calculation result that we cache in
the Timeline::initial_logical_size. Presumably, because there
was confusion around initdb_lsn vs. initial size calculation.

The fix is to only hand out the initialized_size() only if
the LSN matches.

The distinction in the metrics between "init logical size" and "logical
size" was also incorrect because of the above. So, remove it.

There was a special case for `size != 0`. This was to cover the case of
LogicalSize::empty_initial(), but `initial_part_end` is `None` in that
case, so the new `LogicalSize::initialized_size()` will return None
in that case as well.

Lastly, to prevent confusion like this in the future, rename all
occurrences of `init_lsn` to either just `lsn` or a more specific name.

Co-authored-by: Joonas Koivunen <joonas@neon.tech>
Co-authored-by: Heikki Linnakangas <heikki@neon.tech>

2023-03-27 12:45:10 +02:00

..

benches

feat: LayerMap::replace (#3513)

2023-02-03 15:33:46 +02:00

fixtures

walredo: simple tests and bench updates (#3045)

2023-01-16 18:24:45 +02:00

src

fix synthetic size for (last_record_lsn - gc_horizon) < initdb_lsn (#3874)

2023-03-27 12:45:10 +02:00

Cargo.toml

Move async postgres_backend to its own crate.

2023-03-09 20:45:56 +03:00