Specializer SQL support wave 4: join forms — USING, residual ON, semi joins, comma rewrite — corpus 383 → 395 (TASK-50) - #35
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…-ON laziness, comma=probe equivalence (TASK-50) Three-agent fleet, measured before implementation. Headlines: USING's merged column stays at the LEFT position (not hoisted) and equals the left value under INNER/LEFT; LEFT keeps residual-failing key-matches with a NULL side; DuckDB pushes single-side residuals into scans (eager traps) while both-sides residuals are pair-lazy — v0 requires single-side residuals trap-free; comma-join == INNER probe bit-exactly incl. star order; duplicate star names survive to Arrow (our typed model cannot hold them — documented constraint). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
…JoinHit with hit-guarded lazy lowering (TASK-50) The residual evaluates in a branch taken only on a raw key hit (the measured per-candidate-pair laziness), 3VL-collapsed, and the block probe cache is overwritten with the final match so every downstream consumer (INNER skip, LEFT flags, StaticCol, JoinHit) picks it up unchanged. Frontend wiring (bind_on split, USING, comma rewrite, all-key lift, star reconstruction) lands next; all 129 Rust tests green. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
…er-join key reconstruction (TASK-50) bind_on splits equalities-with-a-static-side into probe keys and returns everything else raw; residuals bind with the join in scope and enforce the measured evaluation-order rule (single-side must be trap-free — DuckDB scan-pushes those; both-sides evaluate per candidate pair, our hit-guarded lowering exactly). USING pairs the LEFT scope's binding with this table's column (dedupes silently, ambiguity after an ON join errors like DuckDB) and suppresses the static-side key from stars and bare-name binds (merged column = left value, measured). Key columns reconstruct everywhere via key_lane: INNER = the key expr, LEFT = CASE JoinHit THEN key ELSE NULL. Map statics may now be one-side-empty (semi joins / cross), incl. text-format round-trip. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
…reject — corpus 383 -> 395 (TASK-50) Comma relations rewrite to INNER probes (measured bit-identical incl. star order): WHERE equi conjuncts pairing the current scope with a comma table's column are consumed as its keys, everything else stays WHERE. Keyless comma tables are cross joins via the empty-key map — the duplicate-key check enforces single-entry-ness at compile, and a 0-row static annihilates, both measured. The residual guard now threads the probe's value lanes through the block params / live stack (strict block-param SSA — caught by the corpus, fixed, verifier green). Static values outside BIGINT range (UBIGINT/HUGEINT payloads) reject cleanly. Join-blocked corpus pool: 71 -> 13 (10 dynamic self-joins, 2 NATURAL deeper-blocked by COLUMNS(), 1 FULL OUTER). 15 new join oracle tests. Corpus 395/678, zero FAILs, deterministic; gate green (753 + 13 xfail). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
ahrzb
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Jul 26, 2026
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Wave 4: join forms — USING, residual ON, semi joins, comma rewrite — corpus 383 → 395 (TASK-50)
Pins-first: a three-agent fleet measured DuckDB 1.5.5's join semantics before implementation (
2026-07-26-wave4-join-pins.md+pins-wave4/*.json).What ships (stage A — no new execution model)
JOIN ... USING— measured merged-column semantics mirrored exactly: the merged column sits at the left table's position with the left value (not PostgreSQL's front-hoisting);t1.aandt2.aboth stay addressable (t2.aNULL on a LEFT miss);USING (a, a)dedupes silently; ambiguity after a prior ON join errors like DuckDB.ON l.id = r.id AND l.val > 1on INNER and LEFT:match = key_hit AND residual, evaluated hit-guarded per candidate pair (DuckDB's measured laziness for both-sides residuals, bit-exact). LEFT keeps residual-failing key-matches with an all-NULL right side — the classic ON-vs-WHERE trap, pinned and reproduced. Single-side residuals are restricted to trap-free shapes: DuckDB scan-pushes those, so a trapping one has different error timing — rejected by name rather than silently diverging.r.id≡ CASE match THEN probe-key ELSE NULL). Duplicate-output-name stars stay cleanly unsupported (DuckDB emits duplicate Arrow columns verbatim; a typed output model cannot).FROM t, u WHERE t.k = u.krewrites to the INNER probe (measured bit-identical, star order included); WHERE equi conjuncts are consumed as keys, everything else stays WHERE.Found by the gate
The corpus replay caught a strict-SSA violation in the first residual lowering (probe value lanes crossing blocks without riding params) — fixed by threading them through block params and the live stack. UBIGINT/HUGEINT static payloads now reject cleanly instead of raising a raw OverflowError.
Results
COLUMNS(), 1 FULL OUTER — all named).Stage B (design only, per the ticket's gate)
Output multiplicity for pure non-equi joins:
Term::EmitTocontinuation + per-entry static scan loop; batch-level API only (breaks 1:1 row mapping). Written up in TASK-50 — awaiting a go before any build.🤖 Generated with Claude Code