fix(vector): close local pgvector final review

harness/tht/adapters/vector/pgvector.py

@@ -97,6 +97,13 @@ class PgVectorStore:
             try:
                 with raw.cursor() as cursor:
                     cursor.execute("SELECT 1")
+                    cursor.execute(
+                        "SELECT has_schema_privilege(current_user, %s, 'USAGE')",
+                        (self._schema,),
+                    )
+                    schema_usage = bool(cursor.fetchone()[0])
+                    if not schema_usage:
+                        return False, "vector schema incomplete: missing schema usage", set()
                     cursor.execute(
                         """SELECT c.relname, format_type(a.atttypid, a.atttypmod),
                                   has_table_privilege(current_user, c.oid, 'SELECT'),
@@ -244,8 +251,9 @@ class PgVectorStore:
         if kinds:
             _validate_known_kinds(kinds)
         hits: list[VectorHit] = []
-        raw = self._reader.raw_connection()
+        raw = None
         try:
+            raw = self._reader.raw_connection()
             with raw.cursor() as cursor:
                 for collection in collections:
                     table = _collection(self._schema, collection)
@@ -272,8 +280,13 @@ class PgVectorStore:
                     params.extend((_vector_literal(embedding), limit))
                     cursor.execute(query, params)
                     hits.extend(hit_from_metadata(row[1], row[0]) for row in cursor.fetchall())
+        except VectorStoreError:
+            raise
+        except Exception as exc:
+            raise VectorReadUnavailable("Vector read operation unavailable") from exc
         finally:
-            raw.close()
+            if raw is not None:
+                raw.close()
         return sorted(hits, key=lambda hit: (-hit.similarity, hit.id))[:limit]
 
     def _require_writer(self) -> Engine:
@@ -285,8 +298,9 @@ class PgVectorStore:
         engine = self._require_writer()
         table = _collection(self._schema, collection)
         _validate_collection_kinds(collection, kinds)
-        raw = engine.raw_connection()
+        raw = None
         try:
+            raw = engine.raw_connection()
             with raw.cursor() as cursor:
                 cursor.execute(
                     sql.SQL("SELECT record_key, content_hash FROM {} WHERE kind = ANY(%s)").format(
@@ -295,8 +309,13 @@ class PgVectorStore:
                     (kinds,),
                 )
                 return dict(cursor.fetchall())
+        except VectorStoreError:
+            raise
+        except Exception as exc:
+            raise VectorWriteUnavailable("Vector write operation unavailable") from exc
         finally:
-            raw.close()
+            if raw is not None:
+                raw.close()
 
     def upsert(self, collection: str, records: list[VectorWriteRecord]) -> int:
         engine = self._require_writer()
@@ -317,8 +336,9 @@ class PgVectorStore:
             "UPDATE {} SET kind = %s, content_hash = %s, metadata = %s::jsonb, "
             "embedding = %s::{}, indexed_at = pg_catalog.now() WHERE record_key = %s"
         ).format(table, _vector_type(self._schema))
-        raw = engine.raw_connection()
+        raw = None
         try:
+            raw = engine.raw_connection()
             with raw.cursor() as cursor:
                 for write_record in records:
                     record = write_record.record
@@ -348,11 +368,17 @@ class PgVectorStore:
                             ),
                         )
             raw.commit()
-        except Exception:
-            raw.rollback()
+        except VectorStoreError:
+            if raw is not None:
+                raw.rollback()
             raise
+        except Exception as exc:
+            if raw is not None:
+                raw.rollback()
+            raise VectorWriteUnavailable("Vector write operation unavailable") from exc
         finally:
-            raw.close()
+            if raw is not None:
+                raw.close()
         return len(records)