From 4550983e0ce2f35b3585e53894c941c23693e71d Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Wed, 20 May 2020 13:41:44 -0400
Subject: Performance fixes for new result set

A few small mistakes led to huge callcounts.   Additionally,
the warn-on-get behavior which is attempting to warn for
deprecated access in SQLAlchemy 2.0 is very expensive; it's not clear
if its feasible to have this warning or to somehow alter how it
works.

Fixes: #5340
Change-Id: I73bdd2d7b6f1b25cc0222accabd585cf761a5af4
---
 lib/sqlalchemy/sql/compiler.py   | 19 +++++++++----------
 lib/sqlalchemy/sql/selectable.py | 29 ++++++++++++++++-------------
 2 files changed, 25 insertions(+), 23 deletions(-)

(limited to 'lib/sqlalchemy/sql')

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index d32e3fd7a..ccc1b53fe 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -840,16 +840,17 @@ class SQLCompiler(Compiled):
                     ),
                     replace_context=err,
                 )
-            resolved_extracted = dict(
-                zip([b.key for b in orig_extracted], extracted_parameters)
-            )
+
+            resolved_extracted = {
+                b.key: extracted
+                for b, extracted in zip(orig_extracted, extracted_parameters)
+            }
         else:
             resolved_extracted = None
 
         if params:
             pd = {}
-            for bindparam in self.bind_names:
-                name = self.bind_names[bindparam]
+            for bindparam, name in self.bind_names.items():
                 if bindparam.key in params:
                     pd[name] = params[bindparam.key]
                 elif name in params:
@@ -884,7 +885,7 @@ class SQLCompiler(Compiled):
             return pd
         else:
             pd = {}
-            for bindparam in self.bind_names:
+            for bindparam, name in self.bind_names.items():
                 if _check and bindparam.required:
                     if _group_number:
                         raise exc.InvalidRequestError(
@@ -908,11 +909,9 @@ class SQLCompiler(Compiled):
                     value_param = bindparam
 
                 if bindparam.callable:
-                    pd[
-                        self.bind_names[bindparam]
-                    ] = value_param.effective_value
+                    pd[name] = value_param.effective_value
                 else:
-                    pd[self.bind_names[bindparam]] = value_param.value
+                    pd[name] = value_param.value
             return pd
 
     @property
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index bcab46d84..cc82c509b 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -3527,12 +3527,14 @@ class Select(
     @classmethod
     def _create_select_from_fromclause(cls, target, entities, *arg, **kw):
         if arg or kw:
-            util.warn_deprecated_20(
-                "Passing arguments to %s.select() is deprecated and "
-                "will be removed in SQLAlchemy 2.0.  Please use generative "
-                "methods such as select().where(), etc."
-                % (target.__class__.__name__,)
-            )
+            if util.SQLALCHEMY_WARN_20:
+                util.warn_deprecated_20(
+                    "Passing arguments to %s.select() is deprecated and "
+                    "will be removed in SQLAlchemy 2.0.  "
+                    "Please use generative "
+                    "methods such as select().where(), etc."
+                    % (target.__class__.__name__,)
+                )
             return Select(entities, *arg, **kw)
         else:
             return Select._create_select(*entities)
@@ -3744,13 +3746,14 @@ class Select(
             :meth:`_expression.Select.apply_labels`
 
         """
-        util.warn_deprecated_20(
-            "The select() function in SQLAlchemy 2.0 will accept a "
-            "series of columns / tables and other entities only, "
-            "passed positionally. For forwards compatibility, use the "
-            "sqlalchemy.future.select() construct.",
-            stacklevel=4,
-        )
+        if util.SQLALCHEMY_WARN_20:
+            util.warn_deprecated_20(
+                "The select() function in SQLAlchemy 2.0 will accept a "
+                "series of columns / tables and other entities only, "
+                "passed positionally. For forwards compatibility, use the "
+                "sqlalchemy.future.select() construct.",
+                stacklevel=4,
+            )
 
         self._auto_correlate = correlate
 
-- 
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