Split last_upsert (persisted write) and last_refresh (run liveness) in stats

src/sqlmem/engine.py

@@ -145,17 +145,23 @@ class CachingEngine:
     def stats(self) -> Stats:
         states = self._cache.get_states()
         errors = self._cache.get_errors()
+        last_runs = self._cache.get_last_runs()
         with self._cache._lock:
             base = self._stats.snapshot(self._cache.connection, states)
         base = replace(base, errors=self._cache.error_total)
         return replace(
-            base, tables={n: self._enrich(n, t, errors) for n, t in base.tables.items()}
+            base,
+            tables={n: self._enrich(n, t, errors, last_runs) for n, t in base.tables.items()},
         )
 
     def _enrich(
-        self, name: str, table_stats: TableStats, errors: dict[str, TableError]
+        self,
+        name: str,
+        table_stats: TableStats,
+        errors: dict[str, TableError],
+        last_runs: dict[str, str],
     ) -> TableStats:
-        """Annotate a TableStats with refresh tracking, TTL staleness and errors."""
+        """Annotate a TableStats with refresh tracking, TTL staleness, errors and run time."""
         if name in self._delta:
             tracking = "delta"
         elif name in self._ttl:
@@ -169,17 +175,19 @@ class CachingEngine:
             if age is not None and age > self._ttl[name]:
                 state = TableState.STALE
 
+        last_refresh = last_runs.get(name)
         err = errors.get(name)
         if err is not None:
             return replace(
                 table_stats,
                 tracking=tracking,
                 state=state,
+                last_refresh=last_refresh,
                 last_error=err.message,
                 last_error_at=err.at,
                 consecutive_failures=err.consecutive,
             )
-        return replace(table_stats, tracking=tracking, state=state)
+        return replace(table_stats, tracking=tracking, state=state, last_refresh=last_refresh)
 
     def execute(self, sql: str, params: Params = None) -> list[dict]:
         parsed = parse(sql, params, dialect=self._dialect)