[Bug] Initialize sqlparse lexer prior to using sqlparse

.changes/unreleased/Fixes-20240206-132326.yaml

@@ -0,0 +1,7 @@
+kind: Fixes
+body: Initialize sqlparse.Lexer to resolve issue with `dbt docs generate` that includes
+  external tables
+time: 2024-02-06T13:23:26.061133-05:00
+custom:
+  Author: mikealfare
+  Issue: "710"

dbt/adapters/redshift/connections.py

@@ -354,6 +354,7 @@ def add_query(self, sql, auto_begin=True, bindings=None, abridge_sql_log=False):
         connection = None
         cursor = None
 
+        self._initialize_sqlparse_lexer()
         queries = sqlparse.split(sql)
 
         for query in queries:
@@ -385,3 +386,14 @@ def get_credentials(cls, credentials):
     @classmethod
     def data_type_code_to_name(cls, type_code: Union[int, str]) -> str:
         return get_datatype_name(type_code)
+
+    @staticmethod
+    def _initialize_sqlparse_lexer():
+        """
+        Resolves: https://github.com/dbt-labs/dbt-redshift/issues/710
+        Implementation of this fix: https://github.com/dbt-labs/dbt-core/pull/8215
+        """
+        from sqlparse.lexer import Lexer  # type: ignore
+
+        if hasattr(Lexer, "get_default_instance"):
+            Lexer.get_default_instance()