fix(postgres): allow inference of unknown types

ci/schema/postgresql.sql

@@ -1,6 +1,7 @@
 CREATE EXTENSION IF NOT EXISTS hstore;
 CREATE EXTENSION IF NOT EXISTS postgis;
 CREATE EXTENSION IF NOT EXISTS plpython3u;
+CREATE EXTENSION IF NOT EXISTS vector;
 
 DROP TABLE IF EXISTS diamonds CASCADE;
 
@@ -214,3 +215,7 @@ ADD search tsvector
 GENERATED always AS (
   setweight(to_tsvector('simple', notes), 'A') :: tsvector
 ) stored;
+
+ALTER TABLE awards_players
+ADD simvec vector
+GENERATED always AS ('[1,2,3]' :: vector) stored;

docker/postgres/Dockerfile

@@ -1,2 +1,7 @@
 FROM postgis/postgis:15-3.3-alpine
-RUN apk add postgresql15-plpython3
+RUN apk add --no-cache build-base clang15 llvm15 postgresql15-plpython3 python3 py3-pip && \
+    python3 -m pip install pgxnclient && \
+    pgxn install vector && \
+    python3 -m pip uninstall -y pgxnclient && \
+    rm -rf ~/.cache/pip && \
+    apk del build-base clang15 llvm15 python3 py3-pip

ibis/backends/postgres/__init__.py

@@ -246,6 +246,8 @@ def _metadata(self, query: str) -> Iterable[tuple[str, dt.DataType]]:
   AND attnum > 0
   AND NOT attisdropped
 ORDER BY attnum"""
+        if self.inspector.has_table(query):
+            query = f"TABLE {query}"
         with self.begin() as con:
             con.exec_driver_sql(f"CREATE TEMPORARY VIEW {name} AS {query}")
             type_info = con.execute(

ibis/backends/postgres/datatypes.py

@@ -46,7 +46,14 @@ def _get_type(typestr: str) -> dt.DataType:
     is_array = typestr.endswith(_BRACKETS)
     if (typ := _type_mapping.get(typestr.replace(_BRACKETS, ""))) is not None:
         return dt.Array(typ) if is_array else typ
-    return _parse_numeric(typestr)
+    try:
+        return _parse_numeric(typestr)
+    except parsy.ParseError:
+        # postgres can have arbitrary types unknown to ibis, so we just
+        # consider them null since we can't know what to do with them without
+        # explicit support, return null to effectively give no public API to
+        # such columns
+        return dt.null
 
 
 _type_mapping = {

ibis/backends/postgres/tests/test_client.py

@@ -207,3 +207,11 @@ def test_get_schema_from_query(con, pg_type, expected_type):
     expected_schema = ibis.schema(dict(x=expected_type, y=dt.Array(expected_type)))
     result_schema = con._get_schema_using_query(f"SELECT x, y FROM {name}")
     assert result_schema == expected_schema
+
+
+@pytest.mark.parametrize(
+    ("col", "expected_type"), [("search", dt.string), ("simvec", dt.null)]
+)
+def test_unknown_column_type(con, col, expected_type):
+    awards_players = con.table("awards_players")
+    assert awards_players[col].type() == expected_type

ibis/backends/postgres/tests/test_string.py

@@ -4,7 +4,6 @@
 from pytest import param
 
 import ibis
-import ibis.expr.datatypes as dt
 
 
 @pytest.mark.parametrize(
@@ -17,9 +16,3 @@ def test_special_strings(alltypes, data, data_type):
     expr = alltypes[[alltypes.id, lit]].head(1)
     df = expr.execute()
     assert df['tmp'].iloc[0] == uuid.UUID(data)
-
-
-def test_load_tsvector_table(con):
-    awards_players = con.table("awards_players")
-    assert "search" in awards_players.columns
-    assert awards_players.schema()["search"] == dt.String(nullable=True)