Add documentation + pass connection through to PGDialect._set_backslash_escapes()

diff --git a/doc/build/changelog/unreleased_20/9442.rst b/doc/build/changelog/unreleased_20/9442.rst
new file mode 100644 (file)
index 0000000..2b17219
--- /dev/null
+++ b/doc/build/changelog/unreleased_20/9442.rst
@@ -0,0 +1,7 @@
+.. change::
+      :tags: usecase, postgresql
+      :tickets: 9442
+
+      Modifications to the base PostgreSQL dialect to allow for better integration with the
+      sqlalchemy-redshift third party dialect for SQLAlchemy 2.0. Pull request courtesy
+      matthewgdv.

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 580897f8a1170f0e2f1969ff7b60fd32d163cea7..3c1fc00734f6ac1e6e1dc7f7588ca2d17c91b0c9 100644 (file)
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -3030,7 +3030,7 @@ class PGDialect(default.DefaultDialect):
         # https://www.postgresql.org/docs/9.3/static/release-9-2.html#AEN116689
         self.supports_smallserial = self.server_version_info >= (9, 2)
 
-        self.set_backslash_escapes()
+        self._set_backslash_escapes(connection)
 
         self._supports_drop_index_concurrently = self.server_version_info >= (
             9,
@@ -3038,14 +3038,6 @@ class PGDialect(default.DefaultDialect):
         )
         self.supports_identity_columns = self.server_version_info >= (10,)
 
-    def set_backslash_escapes(self):
-        # this method is provided as an override hook for descendant
-        # dialects (e.g. Redshift), so removing it may break them
-        std_string = connection.exec_driver_sql(
-            "show standard_conforming_strings"
-        ).scalar()
-        self._backslash_escapes = std_string == "off"
-
     def get_isolation_level_values(self, dbapi_conn):
         # note the generic dialect doesn't have AUTOCOMMIT, however
         # all postgresql dialects should include AUTOCOMMIT.
@@ -4704,3 +4696,11 @@ class PGDialect(default.DefaultDialect):
             domains.append(domain_rec)
 
         return domains
+
+    def _set_backslash_escapes(self, connection):
+        # this method is provided as an override hook for descendant
+        # dialects (e.g. Redshift), so removing it may break them
+        std_string = connection.exec_driver_sql(
+            "show standard_conforming_strings"
+        ).scalar()
+        self._backslash_escapes = std_string == "off"