Initial sql compilation caching support

src/sqlalchemy_solr/base.py

@@ -514,6 +514,7 @@ 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/test_sql_compilation_caching.py

@@ -0,0 +1,49 @@
+from sqlalchemy import select
+from sqlalchemy.sql.expression import bindparam
+
+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, caplog, settings):
+        engine, t = prepare_orm(settings)
+
+        qry_1 = (select(t.c.CITY_s).select_from(t)).limit(1)  # pylint: disable=unsubscriptable-object
+        qry_2 = (select(t.c.CITY_s).select_from(t)).limit(10)  # pylint: disable=unsubscriptable-object
+
+        with engine.connect() as connection:
+            connection.execute(qry_1)
+            connection.execute(qry_2)
+
+        assert 'generated in' in caplog.text
+        assert 'cached since' in caplog.text
+
+    def test_sql_compilation_caching_2(self, caplog, settings):
+        engine, t = prepare_orm(settings)
+
+        qry_1 = (select(t.c.CITY_s).select_from(t)).limit(1).offset(1)  # pylint: disable=unsubscriptable-object
+        qry_2 = (select(t.c.CITY_s).select_from(t)).limit(1).offset(2)  # pylint: disable=unsubscriptable-object
+
+        with engine.connect() as connection:
+            connection.execute(qry_1)
+            connection.execute(qry_2)
+
+        assert 'generated in' in caplog.text
+        assert 'cached since' in caplog.text
+
+    def test_sql_compilation_caching_3(self, caplog, settings):
+        engine, t = prepare_orm(settings)
+
+        qry = select(t).where(t.c.CITY_s == bindparam('CITY_s')).limit(10)  # pylint: disable=unsubscriptable-object
+
+        with engine.connect() as connection:
+            connection.execute(qry, params={'CITY_s': 'Singapore'})
+            connection.execute(qry, CITY_s='Boras')
+
+        assert 'generated in' in caplog.text
+        assert 'cached since' in caplog.text