fix: Implements connection pool for postgres online store

sdk/python/feast/infra/online_stores/contrib/postgres.py

@@ -1,3 +1,4 @@
+import contextlib
 import logging
 from collections import defaultdict
 from datetime import datetime
@@ -7,14 +8,15 @@
 import pytz
 from psycopg2 import sql
 from psycopg2.extras import execute_values
+from psycopg2.pool import SimpleConnectionPool
 from pydantic.schema import Literal
 
 from feast import Entity
 from feast.feature_view import FeatureView
 from feast.infra.key_encoding_utils import serialize_entity_key
 from feast.infra.online_stores.online_store import OnlineStore
-from feast.infra.utils.postgres.connection_utils import _get_conn
-from feast.infra.utils.postgres.postgres_config import PostgreSQLConfig
+from feast.infra.utils.postgres.connection_utils import _get_conn, _get_connection_pool
+from feast.infra.utils.postgres.postgres_config import ConnectionType, PostgreSQLConfig
 from feast.protos.feast.types.EntityKey_pb2 import EntityKey as EntityKeyProto
 from feast.protos.feast.types.Value_pb2 import Value as ValueProto
 from feast.repo_config import RepoConfig
@@ -27,12 +29,21 @@ class PostgreSQLOnlineStoreConfig(PostgreSQLConfig):
 
 class PostgreSQLOnlineStore(OnlineStore):
     _conn: Optional[psycopg2._psycopg.connection] = None
+    _conn_pool: Optional[SimpleConnectionPool] = None
 
+    @contextlib.contextmanager
     def _get_conn(self, config: RepoConfig):
-        if not self._conn:
-            assert config.online_store.type == "postgres"
-            self._conn = _get_conn(config.online_store)
-        return self._conn
+        assert config.online_store.type == "postgres"
+        if config.online_store.conn_type == ConnectionType.pool:
+            if not self._conn_pool:
+                self._conn_pool = _get_connection_pool(config.online_store)
+            connection = self._conn_pool.getconn()
+            yield connection
+            self._conn_pool.putconn(connection)
+        else:
+            if not self._conn:
+                self._conn = _get_conn(config.online_store)
+            yield self._conn
 
     @log_exceptions_and_usage(online_store="postgres")
     def online_write_batch(

sdk/python/feast/infra/utils/postgres/connection_utils.py

@@ -5,6 +5,7 @@
 import psycopg2
 import psycopg2.extras
 import pyarrow as pa
+from psycopg2.pool import SimpleConnectionPool
 
 from feast.infra.utils.postgres.postgres_config import PostgreSQLConfig
 from feast.type_map import arrow_to_pg_type
@@ -22,10 +23,28 @@ def _get_conn(config: PostgreSQLConfig):
         sslcert=config.sslcert_path,
         sslrootcert=config.sslrootcert_path,
         options="-c search_path={}".format(config.db_schema or config.user),
+        keepalives_idle=config.keepalives_idle,
     )
     return conn
 
 
+def _get_connection_pool(config: PostgreSQLConfig):
+    return SimpleConnectionPool(
+        config.min_conn,
+        config.max_conn,
+        dbname=config.database,
+        host=config.host,
+        port=int(config.port),
+        user=config.user,
+        password=config.password,
+        sslmode=config.sslmode,
+        sslkey=config.sslkey_path,
+        sslcert=config.sslcert_path,
+        sslrootcert=config.sslrootcert_path,
+        options="-c search_path={}".format(config.db_schema or config.user),
+    )
+
+
 def _df_to_create_table_sql(entity_df, table_name) -> str:
     pa_table = pa.Table.from_pandas(entity_df)
     columns = [

sdk/python/feast/infra/utils/postgres/postgres_config.py

@@ -1,11 +1,20 @@
+from enum import Enum
 from typing import Optional
 
 from pydantic import StrictStr
 
 from feast.repo_config import FeastConfigBaseModel
 
 
+class ConnectionType(Enum):
+    singleton = "singleton"
+    pool = "pool"
+
+
 class PostgreSQLConfig(FeastConfigBaseModel):
+    min_conn: int = 1
+    max_conn: int = 10
+    conn_type: ConnectionType = ConnectionType.singleton
     host: StrictStr
     port: int = 5432
     database: StrictStr
@@ -16,3 +25,4 @@ class PostgreSQLConfig(FeastConfigBaseModel):
     sslkey_path: Optional[StrictStr] = None
     sslcert_path: Optional[StrictStr] = None
     sslrootcert_path: Optional[StrictStr] = None
+    keepalives_idle: int = 0

sdk/python/tests/conftest.py

@@ -393,3 +393,17 @@ def feature_store_for_online_retrieval(
     ]
 
     return fs, feature_refs, entity_rows
+
+
+@pytest.fixture
+def fake_ingest_data():
+    """Fake data to ingest into the feature store"""
+    data = {
+        "driver_id": [1],
+        "conv_rate": [0.5],
+        "acc_rate": [0.6],
+        "avg_daily_trips": [4],
+        "event_timestamp": [pd.Timestamp(datetime.utcnow()).round("ms")],
+        "created": [pd.Timestamp(datetime.utcnow()).round("ms")],
+    }
+    return pd.DataFrame(data)

sdk/python/tests/integration/online_store/test_universal_online.py

@@ -17,6 +17,7 @@
 from feast.feature_service import FeatureService
 from feast.feature_view import FeatureView
 from feast.field import Field
+from feast.infra.utils.postgres.postgres_config import ConnectionType
 from feast.online_response import TIMESTAMP_POSTFIX
 from feast.types import Float32, Int32, String
 from feast.wait import wait_retry_backoff
@@ -32,9 +33,45 @@
 from tests.utils.data_source_test_creator import prep_file_source
 
 
+@pytest.mark.integration
+@pytest.mark.universal_online_stores(only=["postgres"])
+def test_connection_pool_online_stores(
+    environment, universal_data_sources, fake_ingest_data
+):
+    if os.getenv("FEAST_IS_LOCAL_TEST", "False") == "True":
+        return
+    fs = environment.feature_store
+    fs.config.online_store.conn_type = ConnectionType.pool
+    fs.config.online_store.min_conn = 1
+    fs.config.online_store.max_conn = 10
+
+    entities, datasets, data_sources = universal_data_sources
+    driver_hourly_stats = create_driver_hourly_stats_feature_view(data_sources.driver)
+    driver_entity = driver()
+
+    # Register Feature View and Entity
+    fs.apply([driver_hourly_stats, driver_entity])
+
+    # directly ingest data into the Online Store
+    fs.write_to_online_store("driver_stats", fake_ingest_data)
+
+    # assert the right data is in the Online Store
+    df = fs.get_online_features(
+        features=[
+            "driver_stats:avg_daily_trips",
+            "driver_stats:acc_rate",
+            "driver_stats:conv_rate",
+        ],
+        entity_rows=[{"driver_id": 1}],
+    ).to_df()
+    assertpy.assert_that(df["avg_daily_trips"].iloc[0]).is_equal_to(4)
+    assertpy.assert_that(df["acc_rate"].iloc[0]).is_close_to(0.6, 1e-6)
+    assertpy.assert_that(df["conv_rate"].iloc[0]).is_close_to(0.5, 1e-6)
+
+
 @pytest.mark.integration
 @pytest.mark.universal_online_stores(only=["redis"])
-def test_entity_ttl_online_store(environment, universal_data_sources):
+def test_entity_ttl_online_store(environment, universal_data_sources, fake_ingest_data):
     if os.getenv("FEAST_IS_LOCAL_TEST", "False") == "True":
         return
     fs = environment.feature_store
@@ -47,19 +84,8 @@ def test_entity_ttl_online_store(environment, universal_data_sources):
     # Register Feature View and Entity
     fs.apply([driver_hourly_stats, driver_entity])
 
-    # fake data to ingest into Online Store
-    data = {
-        "driver_id": [1],
-        "conv_rate": [0.5],
-        "acc_rate": [0.6],
-        "avg_daily_trips": [4],
-        "event_timestamp": [pd.Timestamp(datetime.datetime.utcnow()).round("ms")],
-        "created": [pd.Timestamp(datetime.datetime.utcnow()).round("ms")],
-    }
-    df_ingest = pd.DataFrame(data)
-
     # directly ingest data into the Online Store
-    fs.write_to_online_store("driver_stats", df_ingest)
+    fs.write_to_online_store("driver_stats", fake_ingest_data)
 
     # assert the right data is in the Online Store
     df = fs.get_online_features(