escape the wildcard underscore in postgres "like" queries (#1960)

plugins/postgres/dbt/include/postgres/macros/catalog.sql

@@ -29,7 +29,7 @@
     join pg_catalog.pg_attribute col on col.attrelid = tbl.oid
 
     where sch.nspname != 'information_schema'
-      and sch.nspname not like 'pg_%' -- avoid postgres system schemas
+      and sch.nspname not like 'pg\_%' -- avoid postgres system schemas, '_' is a wildcard so escape it
       and not pg_is_other_temp_schema(sch.oid) -- not a temporary schema belonging to another session
       and tbl.relpersistence = 'p' -- [p]ermanent table. Other values are [u]nlogged table, [t]emporary table
       and tbl.relkind in ('r', 'v', 'f', 'p') -- o[r]dinary table, [v]iew, [f]oreign table, [p]artitioned table. Other values are [i]ndex, [S]equence, [c]omposite type, [t]OAST table, [m]aterialized view

plugins/postgres/dbt/include/postgres/macros/relations.sql

@@ -32,7 +32,7 @@
             pg_namespace.oid as id,
             pg_namespace.nspname as name
         from pg_namespace
-        where nspname != 'information_schema' and nspname not like 'pg_%'
+        where nspname != 'information_schema' and nspname not like 'pg\_%'
     ),
     referenced as (
         select

plugins/redshift/dbt/include/redshift/macros/catalog.sql

@@ -95,7 +95,7 @@
     join table_owners using (table_database, table_schema, table_name)
 
     where table_schema != 'information_schema'
-      and table_schema not like 'pg_%'
+      and table_schema not like 'pg\_%'
 
     order by "column_index"
   {%- endcall -%}

test/integration/029_docs_generate_tests/test_docs_generate.py

@@ -1,6 +1,8 @@
 import hashlib
 import json
 import os
+import random
+import time
 from datetime import datetime
 from unittest.mock import ANY, patch
 
@@ -53,6 +55,38 @@ def walk_files(path):
             yield os.path.join(root, basename)
 
 
+class TestDocsGenerateEscapes(DBTIntegrationTest):
+    prefix = "pgtest{}{:04}".format(int(time.time()), random.randint(0, 9999))
+
+    @property
+    def schema(self):
+        return 'docs_generate_029'
+
+    @staticmethod
+    def dir(path):
+        return normalize(path)
+
+    @property
+    def models(self):
+        return self.dir("trivial_models")
+
+    def run_and_generate(self):
+        self.assertEqual(len(self.run_dbt(['run'])), 1)
+        os.remove(normalize('target/manifest.json'))
+        os.remove(normalize('target/run_results.json'))
+        self.run_dbt(['docs', 'generate'])
+
+    @use_profile('postgres')
+    def test_postgres_include_schema(self):
+        self.run_and_generate()
+        manifest = _read_json('./target/manifest.json')
+        self.assertIn('nodes', manifest)
+        self.assertEqual(len(manifest['nodes']), 1)
+        self.assertIn('model.test.model', manifest['nodes'])
+        self.assertIn('schema', manifest['nodes']['model.test.model'])
+        self.assertEqual('pg', manifest['nodes']['model.test.model']['schema'][:2])
+
+
 class TestDocsGenerate(DBTIntegrationTest):
     setup_alternate_db = True
 

test/integration/029_docs_generate_tests/trivial_models/model.sql

@@ -0,0 +1 @@
+select 1 as id