Revise psycopg2 execute_values approach

Revised the approach for the just added support for the psycopg2
"execute_values()" feature added in 1.3.7 for :ticket:`4623`.  The approach
relied upon a regular expression that would fail to match for a more
complex INSERT statement such as one which had subqueries involved.   The
new approach matches exactly the string that was rendered as the VALUES
clause.

Fixes: #4623
Change-Id: Icaae0f7b6bcf87a2cf5c6290a839c8429dd5fac3

1 files changed, 13 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 8bd2249e2..fa7eeaecf 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -498,6 +498,15 @@ class SQLCompiler(Compiled):
 
     """
 
+    insert_single_values_expr = None
+    """When an INSERT is compiled with a single set of parameters inside
+    a VALUES expression, the string is assigned here, where it can be
+    used for insert batching schemes to rewrite the VALUES expression.
+
+    .. versionadded:: 1.3.8
+
+    """
+
     insert_prefetch = update_prefetch = ()
 
     def __init__(
@@ -2512,7 +2521,10 @@ class SQLCompiler(Compiled):
                 )
             )
         else:
-            text += " VALUES (%s)" % ", ".join([c[1] for c in crud_params])
+            insert_single_values_expr = ", ".join([c[1] for c in crud_params])
+            text += " VALUES (%s)" % insert_single_values_expr
+            if toplevel:
+                self.insert_single_values_expr = insert_single_values_expr
 
         if insert_stmt._post_values_clause is not None:
             post_values_clause = self.process(