postgres: add exponential backoff to connection retries (dbt-labs#5503)

add exponential backoff to postgres connection retries

.changes/unreleased/Features-20220720-171257.yaml

@@ -0,0 +1,7 @@
+kind: Features
+body: add exponential backoff to connection retries on Postgres (and Redshift)
+time: 2022-07-20T17:12:57.486949-04:00
+custom:
+  Author: nathaniel-may
+  Issue: "5502"
+  PR: "5503"

plugins/postgres/dbt/adapters/postgres/connections.py

@@ -145,11 +145,15 @@ def connect():
             psycopg2.errors.OperationalError,
         ]
 
+        def exponential_backoff(attempt: int):
+            return attempt * attempt
+
         return cls.retry_connection(
             connection,
             connect=connect,
             logger=logger,
             retry_limit=credentials.retries,
+            retry_timeout=exponential_backoff,
             retryable_exceptions=retryable_exceptions,
         )