Builds on @ms-alan's label fix: the negative figure had a second cause
that relabelling alone leaves in place.
`hermes sessions optimize-storage` reported "reclaimed -3820.1 MB" on a
database that had in fact shrunk 60% (25069 MB -> 9975 MB). Both figures
came from os.path.getsize(). In WAL mode a VACUUM's rewrite lands in the
-wal file, and the checkpoint that folds it back is REFUSED
(SQLITE_BUSY) while any other connection holds a read-mark — e.g. the
live gateway. So the main file still carried its pre-VACUUM size AND kept
growing while the command ran, making the after-figure larger than the
before-figure. The TRUNCATE checkpoint in close() lands after the caller
has already measured and printed.
- hermes_state.py: add SessionDB.logical_size_bytes() — page_count *
page_size, the size the file settles at once the WAL is folded back.
Correct immediately, readers or not; returns None when the connection
is gone so callers fall back to stat().
- hermes_state.py: best-effort TRUNCATE checkpoint after the optimize
VACUUM so the file settles promptly when nothing else holds the DB.
Documented as insufficient alone (busy under a live gateway) so the
stat() approach is not reintroduced.
- hermes_cli/main.py: both `optimize-storage` and `optimize` report via
logical_size_bytes(); fixing only the reported command would have left
the same bug class next door.
- hermes_cli/main.py: lift the contributor's inline label to a
module-level _size_delta_label() shared by both sites, so the "grew by"
wording is consistent and unit-testable without reading source.
The two halves are complementary: page accounting removes the phantom
negative, and "grew by" still covers a genuine increase when concurrent
session writes outweigh what the rebuild freed.
Verified: sabotaging logical_size_bytes() back to stat() fails the new
test with a 22 MB overstatement, reproducing the report. The test asserts
its own precondition (stat() must actually be lagging) so it cannot
silently stop exercising the bug.
Tests: 464 passed (test_hermes_state.py + the new label tests).
Co-authored-by: chenbin <h-chenbin@voyah.com.cn>
teknium1
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