Convert execution to move through Session

This patch replaces the ORM execution flow with a
single pathway through Session.execute() for all queries,
including Core and ORM.

Currently included is full support for ORM Query,
Query.from_statement(), select(), as well as the
baked query and horizontal shard systems.  Initial
changes have also been made to the dogpile caching
example, which like baked query makes use of a
new ORM-specific execution hook that replaces the
use of both QueryEvents.before_compile() as well
as Query._execute_and_instances() as the central
ORM interception hooks.

select() and Query() constructs alike can be passed to
Session.execute() where they will return ORM
results in a Results object.   This API is currently
used internally by Query.   Full support for
Session.execute()->results to behave in a fully
2.0 fashion will be in later changesets.

bulk update/delete with ORM support will also
be delivered via the update() and delete()
constructs, however these have not yet been adapted
to the new system and may follow in a subsequent
update.

Performance is also beginning to lag as of this
commit and some previous ones.   It is hoped that
a few central functions such as the coercions
functions can be rewritten in C to re-gain
performance.  Additionally, query caching
is now available and some subsequent patches
will attempt to cache more of the per-execution
work from the ORM layer, e.g. column getters
and adapters.

This patch also contains initial "turn on" of the
caching system enginewide via the query_cache_size
parameter to create_engine(). Still defaulting at
zero for "no caching".   The caching system still
needs adjustments in order to gain adequate performance.

Change-Id: I047a7ebb26aa85dc01f6789fac2bff561dcd555d

1 files changed, 22 insertions, 6 deletions

diff --git a/test/sql/test_compiler.py b/test/sql/test_compiler.py
index c580e972d..efe4d08c5 100644
--- a/test/sql/test_compiler.py
+++ b/test/sql/test_compiler.py
@@ -84,6 +84,7 @@ from sqlalchemy.testing import eq_
 from sqlalchemy.testing import eq_ignore_whitespace
 from sqlalchemy.testing import fixtures
 from sqlalchemy.testing import is_
+from sqlalchemy.testing import mock
 from sqlalchemy.util import u
 
 table1 = table(
@@ -5198,9 +5199,16 @@ class ResultMapTest(fixtures.TestBase):
 
         wrapped_again = select([c for c in wrapped.c])
 
-        compiled = wrapped_again.compile(
-            compile_kwargs={"select_wraps_for": stmt}
-        )
+        dialect = default.DefaultDialect()
+
+        with mock.patch.object(
+            dialect.statement_compiler,
+            "translate_select_structure",
+            lambda self, to_translate, **kw: wrapped_again
+            if to_translate is stmt
+            else to_translate,
+        ):
+            compiled = stmt.compile(dialect=dialect)
 
         proxied = [obj[0] for (k, n, obj, type_) in compiled._result_columns]
         for orig_obj, proxied_obj in zip(orig, proxied):
@@ -5245,9 +5253,17 @@ class ResultMapTest(fixtures.TestBase):
         # so the compiler logic that matches up the "wrapper" to the
         # "select_wraps_for" can't use inner_columns to match because
         # these collections are not the same
-        compiled = wrapped_again.compile(
-            compile_kwargs={"select_wraps_for": stmt}
-        )
+
+        dialect = default.DefaultDialect()
+
+        with mock.patch.object(
+            dialect.statement_compiler,
+            "translate_select_structure",
+            lambda self, to_translate, **kw: wrapped_again
+            if to_translate is stmt
+            else to_translate,
+        ):
+            compiled = stmt.compile(dialect=dialect)
 
         proxied = [obj[0] for (k, n, obj, type_) in compiled._result_columns]
         for orig_obj, proxied_obj in zip(orig, proxied):