After 9cff677 the loop over the other device's confirmed and ignored faces
(13,000 on the reference library) still asked three cached statements per
face -- the person by uuid, the face's current assignment, and whether this
pair was rejected here. It was 51 ms of a steady-state merge.
The person is now resolved in the statement that reads the incoming rows,
by the local `people.uuid` key:
SCAN fp
SEARCH p USING INTEGER PRIMARY KEY (rowid=?)
SEARCH lp USING COVERING INDEX sqlite_autoindex_people_1 (uuid=?)
and the local `face_person` (16,800 rows) and `face_person_rejected` are
each read once into memory and looked up there. A write goes to the table
and to the map, so a second remote face matched to the same local face sees
what the first left, as it did when each face re-read the table. The
incoming rows are ordered by face id -- the order the table was already
walked in -- since which of two such faces is applied last decides the
answer. An inner join to `people` drops the rows the old loop skipped for
want of a local person, and the counts in the report are unchanged.
After: the loop 10-12 ms. The merge as a whole, with the two changes before
this, went from 228-231 ms to 135 ms best of 5, and every catalog table
checksums the same after the bench as after the old build's run.
dtourolle
ce6705be89