SQL Compilation Caching Support

README.md

@@ -70,6 +70,10 @@ Multi-value fields are mapped to SQL arrays of a specific scalar type. For examp
 phones = Column('PHONE_ss', ARRAY(String))
 ```
 
+### SQL Compilation Caching
+
+The dialect supports caching by leveraging SQLAlchemy SQL compilation caching capabilities, which include query caching.
+
 ### Schema
 
 If the ORM query supplied explicitly refers to a schema, the schema would be filtered out before query execution.

src/sqlalchemy_solr/base.py

@@ -526,6 +526,7 @@ class SolrDialect(default.DefaultDialect):
     returns_unicode_strings = True
     description_encoding = None
     supports_native_boolean = True
+    supports_statement_cache = True
 
     def __init__(self, **kw):
         default.DefaultDialect.__init__(self, **kw)

src/sqlalchemy_solr/http.py

@@ -37,6 +37,8 @@
 class SolrDialect_http(SolrDialect):    # pylint: disable=invalid-name
     # pylint: disable=abstract-method,too-many-instance-attributes
 
+    supports_statement_cache = True
+
     mf = MessageFormatter()
 
     def __init__(self, **kw):

tests/setup.py

@@ -18,7 +18,6 @@ def prepare_orm(settings):
         settings["SOLR_CONNECTION_URI"]
         + "/"
         + settings["SOLR_WORKER_COLLECTION_NAME"],
-        echo=True,
     )
     t = Table(
         settings["SOLR_WORKER_COLLECTION_NAME"],

tests/test_sql_compilation_caching.py

@@ -0,0 +1,57 @@
+from sqlalchemy import select
+from sqlalchemy.sql.expression import bindparam
+from sqlalchemy.util.langhelpers import _symbol
+
+from tests.setup import prepare_orm
+from .fixtures.fixtures import SalesFixture
+
+class TestSQLCompilationCaching:
+    def index_data(self, settings):
+        f = SalesFixture(settings)
+        f.truncate_collection()
+        f.index()
+
+    def test_sql_compilation_caching_1(self, settings):
+        _, t = prepare_orm(settings)
+
+        qry_1 = (select(t.c.CITY_s).select_from(t)).limit(1)
+        qry_2 = (select(t.c.CITY_s).select_from(t)).limit(10)
+
+        k1 = qry_1._generate_cache_key()    # pylint: disable=protected-access
+        k2 = qry_2._generate_cache_key()    # pylint: disable=protected-access
+
+        assert k1 == k2
+
+    def test_sql_compilation_caching_2(self, settings):
+        _, t = prepare_orm(settings)
+
+        qry_1 = (select(t.c.CITY_s).select_from(t)).limit(1).offset(1)
+        qry_2 = (select(t.c.CITY_s).select_from(t)).limit(1).offset(2)
+
+        k1 = qry_1._generate_cache_key()    # pylint: disable=protected-access
+        k2 = qry_2._generate_cache_key()    # pylint: disable=protected-access
+
+        assert k1 == k2
+
+    def test_sql_compilation_caching_3(self, settings):
+        engine, t = prepare_orm(settings)
+
+        qry = select(t).where(t.c.CITY_s == bindparam('CITY_s')).limit(10)
+
+        with engine.connect() as connection:
+            result_1 = connection.execute(qry, {'CITY_s': 'Singapore'})
+            result_2 = connection.execute(qry, {'CITY_s': 'Boras'})
+
+        assert result_1.context.cache_hit == _symbol('CACHE_MISS')
+        assert result_2.context.cache_hit == _symbol('CACHE_HIT')
+
+    def test_sql_compilation_caching_4(self, settings):
+        _, t = prepare_orm(settings)
+
+        qry_1 = select(t).where(t.c.CITY_s == bindparam('CITY_s')).limit(10)
+        qry_2 = select(t).where(t.c.COUNTRY_s == bindparam('COUNTRY_s')).limit(10)
+
+        k1 = qry_1._generate_cache_key()    # pylint: disable=protected-access
+        k2 = qry_2._generate_cache_key()    # pylint: disable=protected-access
+
+        assert k1 != k2