diff --git a/core/dbt/task/docs/generate.py b/core/dbt/task/docs/generate.py
index 5043a1d54cb..550ae32276a 100644
--- a/core/dbt/task/docs/generate.py
+++ b/core/dbt/task/docs/generate.py
@@ -114,12 +114,10 @@ def add_column(self, data: PrimitiveDict):
         table.columns[column.name] = column
 
     def make_unique_id_map(
-        self, manifest: Manifest, selected_node_ids: Optional[Set[UniqueId]] = None
+        self, manifest: Manifest
     ) -> Tuple[Dict[str, CatalogTable], Dict[str, CatalogTable]]:
         """
-        Create mappings between CatalogKeys and CatalogTables for nodes and sources, filtered by selected_node_ids.
-
-        By default, selected_node_ids is None and all nodes and sources defined in the manifest are included in the mappings.
+        Create mappings between CatalogKeys and CatalogTables for nodes and sources.
         """
         nodes: Dict[str, CatalogTable] = {}
         sources: Dict[str, CatalogTable] = {}
@@ -130,8 +128,7 @@ def make_unique_id_map(
             key = table.key()
             if key in node_map:
                 unique_id = node_map[key]
-                if selected_node_ids is None or unique_id in selected_node_ids:
-                    nodes[unique_id] = table.replace(unique_id=unique_id)
+                nodes[unique_id] = table.replace(unique_id=unique_id)
 
             unique_ids = source_map.get(table.key(), set())
             for unique_id in unique_ids:
@@ -142,8 +139,7 @@ def make_unique_id_map(
                         table.to_dict(omit_none=True),
                     )
                 else:
-                    if selected_node_ids is None or unique_id in selected_node_ids:
-                        sources[unique_id] = table.replace(unique_id=unique_id)
+                    sources[unique_id] = table.replace(unique_id=unique_id)
         return nodes, sources
 
 
@@ -247,11 +243,9 @@ def run(self) -> CatalogArtifact:
         if self.manifest is None:
             raise DbtInternalError("self.manifest was None in run!")
 
-        selected_node_ids: Optional[Set[UniqueId]] = None
         if self.args.empty_catalog:
             catalog_table: agate.Table = agate.Table([])
             exceptions: List[Exception] = []
-            selected_node_ids = set()
         else:
             adapter = get_adapter(self.config)
             with adapter.connection_named("generate_catalog"):
@@ -269,7 +263,6 @@ def run(self) -> CatalogArtifact:
                     selected_source_nodes = self._get_nodes_from_ids(
                         self.manifest, selected_source_ids
                     )
-                    selected_node_ids.update(selected_source_ids)
                     selected_nodes.extend(selected_source_nodes)
 
                     relations = {
@@ -301,7 +294,7 @@ def run(self) -> CatalogArtifact:
         if exceptions:
             errors = [str(e) for e in exceptions]
 
-        nodes, sources = catalog.make_unique_id_map(self.manifest, selected_node_ids)
+        nodes, sources = catalog.make_unique_id_map(self.manifest)
         results = self.get_catalog_results(
             nodes=nodes,
             sources=sources,
diff --git a/tests/functional/docs/test_generate.py b/tests/functional/docs/test_generate.py
index de9163ca743..868f1347870 100644
--- a/tests/functional/docs/test_generate.py
+++ b/tests/functional/docs/test_generate.py
@@ -18,12 +18,12 @@
 
 sample_config = """
 sources:
-  - name: my_seed
+  - name: my_source_schema
     schema: "{{ target.schema }}"
     tables:
-      - name: sample_seed
-      - name: second_seed
-      - name: fake_seed
+      - name: sample_source
+      - name: second_source
+      - name: non_existent_source
 """
 
 
@@ -81,7 +81,13 @@ def test_select_limits_no_match(self, project):
 
 class TestGenerateCatalogWithSources(TestBaseGenerate):
     def test_catalog_with_sources(self, project):
+        # populate sources other than non_existent_source
+        project.run_sql("create table {}.sample_source (id int)".format(project.test_schema))
+        project.run_sql("create table {}.second_source (id int)".format(project.test_schema))
+
+        # build nodes
         run_dbt(["build"])
+
         catalog = run_dbt(["docs", "generate"])
 
         # 2 seeds + 2 models
@@ -92,7 +98,7 @@ def test_catalog_with_sources(self, project):
 
 class TestGenerateCatalogWithExternalNodes(TestBaseGenerate):
     @mock.patch("dbt.plugins.get_plugin_manager")
-    def test_catalog_with_sources(self, get_plugin_manager, project):
+    def test_catalog_with_external_node(self, get_plugin_manager, project):
         project.run_sql("create table {}.external_model (id int)".format(project.test_schema))
 
         run_dbt(["build"])
@@ -114,12 +120,15 @@ def test_catalog_with_sources(self, get_plugin_manager, project):
 
 class TestGenerateSelectSource(TestBaseGenerate):
     def test_select_source(self, project):
-        run_dbt(["build"])
+        project.run_sql("create table {}.sample_source (id int)".format(project.test_schema))
+        project.run_sql("create table {}.second_source (id int)".format(project.test_schema))
 
         # 2 sources, 1 selected
-        catalog = run_dbt(["docs", "generate", "--select", "source:test.my_seed.sample_seed"])
+        catalog = run_dbt(
+            ["docs", "generate", "--select", "source:test.my_source_schema.sample_source"]
+        )
         assert len(catalog.sources) == 1
-        assert "source.test.my_seed.sample_seed" in catalog.sources
+        assert "source.test.my_source_schema.sample_source" in catalog.sources
         # no nodes selected
         assert len(catalog.nodes) == 0