Fix SQL compare stall: detach progress commits and skip small sheets.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/biz_state/compare_service.py

@@ -1794,7 +1794,7 @@ def _run_sheet(
             on_load_progress(side, n)
 
     # PostgreSQL path: pushdown-safe sheets join in-DB (BGP-scale).
-    from .compare_sql import run_sql_sheet_compare, sql_compare_skip_reason
+    from .compare_sql import SqlCompareSkip, run_sql_sheet_compare, sql_compare_skip_reason
 
     skip_reason = sql_compare_skip_reason(
         db,
@@ -1834,6 +1834,18 @@ def _run_sheet(
                 diffs=list(result.get("diffs") or []),
                 mapping_stats=dict(result.get("mapping_stats") or {}),
             )
+        except SqlCompareSkip as skip:
+            skip_reason = skip.reason or "skip"
+            _log.info(
+                "python compare sheet=%s metric=%s skip_sql=%s",
+                sheet_key(sheet),
+                mid,
+                skip_reason,
+            )
+            try:
+                db.rollback()
+            except Exception:
+                pass
         except Exception:
             _log.exception(
                 "sql compare fallback sheet=%s metric=%s — using Python engine",
@@ -1841,6 +1853,11 @@ def _run_sheet(
                 mid,
             )
             skip_reason = "sql_error_fallback"
+            # Roll back aborted SQL transaction so Python path can use the session
+            try:
+                db.rollback()
+            except Exception:
+                pass
     else:
         _log.info(
             "python compare sheet=%s metric=%s skip_sql=%s",
@@ -2002,9 +2019,14 @@ def _set_run_progress(
     sheet: dict[str, Any] | None,
     started_mono: float,
     extra: dict[str, Any] | None = None,
+    detach: bool = False,
 ) -> None:
+    """Update run progress.
+
+    ``detach=True`` writes via a fresh session so SQL compare can keep an open
+    transaction (TEMP CTAS) without mid-flight commits on the worker ``db``.
+    """
     elapsed_ms = int((time.monotonic() - started_mono) * 1000)
-    prev = dict(run.summary_json or {})
     progress = {
         "phase": phase,
         "sheet_index": sheet_index,
@@ -2015,6 +2037,39 @@ def _set_run_progress(
     }
     if extra:
         progress.update(extra)
+    title = progress["sheet_title"] or progress["sheet_id"] or ""
+    message = (
+        f"{phase} {sheet_index}/{sheet_total}"
+        + (f" · {title}" if title else "")
+        + f" · {elapsed_ms // 1000}s"
+    )[:1024]
+
+    if detach:
+        from ..db import SessionLocal
+
+        s = SessionLocal()
+        try:
+            r = s.get(BizCompareRun, str(run.id))
+            if not r:
+                return
+            prev = dict(r.summary_json or {})
+            prev["progress"] = progress
+            r.summary_json = prev
+            if str(r.status or "") != "cancelled":
+                r.status = "running"
+                r.message = message
+            s.commit()
+            # Mirror into worker instance for later in-memory reads (do not commit db)
+            prev_w = dict(run.summary_json or {})
+            prev_w["progress"] = progress
+            run.summary_json = prev_w
+            if str(run.status or "") != "cancelled":
+                run.message = message
+        finally:
+            s.close()
+        return
+
+    prev = dict(run.summary_json or {})
     prev["progress"] = progress
     run.summary_json = prev
     # Re-read status from DB — cancel may have been committed by another session
@@ -2022,12 +2077,7 @@ def _set_run_progress(
     db.expire(run, ["status", "message"])
     if str(run.status or "") != "cancelled":
         run.status = "running"
-        title = progress["sheet_title"] or progress["sheet_id"] or ""
-        run.message = (
-            f"{phase} {sheet_index}/{sheet_total}"
-            + (f" · {title}" if title else "")
-            + f" · {elapsed_ms // 1000}s"
-        )[:1024]
+        run.message = message
     db.commit()
 
 
@@ -2146,6 +2196,7 @@ def _execute_compare_into_run(db: Session, run_id: str) -> dict[str, Any]:
                 }
                 if note:
                     extra["engine_note"] = str(note)[:128]
+                # SQL path: detach progress commits so TEMP CTAS stays in one txn
                 _set_run_progress(
                     db,
                     run,
@@ -2155,6 +2206,7 @@ def _execute_compare_into_run(db: Session, run_id: str) -> dict[str, Any]:
                     sheet=_sheet,
                     started_mono=started_mono,
                     extra=extra,
+                    detach=(eng == "sql"),
                 )
 
             _set_run_progress(

netx_api/biz_state/compare_sql.py

@@ -18,7 +18,20 @@ from .compare_rules import effective_compare_fields, field_rule_map
 
 _log = logging.getLogger("netx.biz_state.compare_sql")
 
+# Below this, Python hash-join is faster and avoids TEMP CTAS / progress races.
+_SQL_MIN_ROWS = 20_000
+# Cap a single SQL statement so a stuck planner/lock surfaces as fallback.
+_SQL_STATEMENT_TIMEOUT_MS = 180_000
+
 _FIELD_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$")
+
+
+class SqlCompareSkip(Exception):
+    """Soft skip — caller should use the Python engine (not an error)."""
+
+    def __init__(self, reason: str) -> None:
+        super().__init__(reason)
+        self.reason = str(reason or "skip")
 _SQL_FILTER_OPS = frozenset(
     {"eq", "==", "ne", "!=", "in", "not_in", "nin", "contains", "empty", "not_empty", "nonempty", "ci_eq"}
 )
@@ -381,6 +394,9 @@ def run_sql_sheet_compare(
     tb = f"_netx_cmp_b_{tag}"
     ta = f"_netx_cmp_a_{tag}"
 
+    # Keep worker transaction open across CTAS — progress must NOT commit this session.
+    db.execute(text(f"SET LOCAL statement_timeout = '{int(_SQL_STATEMENT_TIMEOUT_MS)}'"))
+
     _prog("before", 0, phase="sql_count", note="count")
 
     # Raw counts (no row_filters)
@@ -407,13 +423,20 @@ def run_sql_sheet_compare(
     )
     _prog("after", raw_a, phase="sql_count")
 
+    if max(raw_b, raw_a) < int(_SQL_MIN_ROWS):
+        raise SqlCompareSkip("small_sheet")
+
     base_params = {"bid": bid_b, "mid": mid, **filter_params}
-    # Build TEMP sides
-    for tname, batch_id, side in ((tb, bid_b, "before"), (ta, bid_a, "after")):
+    # Build TEMP sides (one transaction — no mid-flight commits on ``db``)
+    _prog("before", raw_b, phase="sql_project", note="temp_before")
+    for tname, batch_id, side, note in (
+        (tb, bid_b, "before", "temp_before"),
+        (ta, bid_a, "after", "temp_after"),
+    ):
         db.execute(text(f"DROP TABLE IF EXISTS {tname}"))
         params = {**base_params, "bid": batch_id}
-        _prog(side, raw_b if side == "before" else raw_a, phase="sql_project", note="temp")
-        # PRESERVE ROWS: compare progress commits must not drop temps mid-run
+        if side == "after":
+            _prog(side, raw_a, phase="sql_project", note=note)
         db.execute(
             text(
                 f"""
@@ -434,7 +457,9 @@ def run_sql_sheet_compare(
             ),
             params,
         )
-        db.execute(text(f"CREATE INDEX ON {tname} (rk) WHERE dup_rn = 1"))
+        db.execute(
+            text(f"CREATE INDEX IF NOT EXISTS {tname}_rk ON {tname} (rk) WHERE dup_rn = 1")
+        )
 
     before_n = int(
         db.execute(text(f"SELECT count(*) FROM {tb}")).scalar() or 0