A merge wrote each inserted row one by one: a savepoint for the domain
row, another for its tracker, two statements each, and then read every
tracker back to record attempted values. A device's first push of a
library of 8,000 cards (24,650 changes) took the server 34 to 37 s, nearly
all of it in those round trips.
A batch the projection pass leaves out (nothing in it touches a foreign
key or a unique index, or its inserts are proven to change no decision)
now writes its new rows many to a statement, up to 1,000 at a time, in
one savepoint: each table's domain rows in one insert, parents' tables
first, then their trackers. A row qualifies when the batch inserts it once
and touches it no other way, no tracker exists for it, nothing earlier in
the batch names it, and every row of the batch it names was written
before it. Its values are planned in the batch's order, as the per-row
path plans them. A chunk whose writes fail (a row there already, perhaps
another space's) is rolled back, the presence it claimed for its rows is
forgotten, and it and every row after it are left to the per-row path,
which tells those cases apart. Attempted values read the trackers the
merge holds instead of querying them.
The proof for merged inserts also accepts a parent of the row's own
table inserted earlier in the batch, so a library's nested studysets no
longer send its first push through the pass; a chunk ends before a row
whose parent of its own table it holds. A row naming itself, or a parent
inserted after it, still takes the pass.
Measured on PostgreSQL, the 24,650 changes merge in about 5 s instead of
34 to 37 s, and with the studysets nested instead of 41 s. A device on
SQLite, whose adapter still inserts row by row, receives the library in
44 s instead of 60 s. The new tests cover a batch spanning chunks, a chunk
failing on a row whose tracker was lost and falling back, and a tree of
one table's rows inserted parents first (the shortcut, a chunk per level)
and children first (the pass). The core, server, integration and
simulation suites pass, but for two PostgreSQL tests that can't start
their database while another embedded PostgreSQL runs.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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