diff --git a/edb/schema/indexes.py b/edb/schema/indexes.py
index bbcc21e07c3..08e2863a7e4 100644
--- a/edb/schema/indexes.py
+++ b/edb/schema/indexes.py
@@ -71,21 +71,19 @@ def is_index_valid_for_type(
     schema: s_schema.Schema,
     context: sd.CommandContext,
 ) -> bool:
-    index_name = str(index.get_name(schema))
+    index_allows_tuples = is_index_supporting_tuples(index, schema)
 
     for index_match in schema.get_referrers(
         index, scls_type=IndexMatch, field_name='index',
     ):
         valid_type = index_match.get_valid_type(schema)
-        if index_name == 'std::fts::index':
-            # FTS index works not only on its valid type (document), but also
-            # on tuples comtaining document as an element.
+        if index_allows_tuples:
             if is_subclass_or_tuple(expr_type, valid_type, schema):
                 return True
         elif expr_type.issubclass(schema, valid_type):
             return True
 
-    if context.testmode and index_name == 'default::test':
+    if context.testmode and str(index.get_name(schema)) == 'default::test':
         # For functional tests of abstract indexes.
         return expr_type.issubclass(
             schema,
@@ -95,6 +93,21 @@ def is_index_valid_for_type(
     return False
 
 
+def is_index_supporting_tuples(
+    index: Index,
+    schema: s_schema.Schema,
+) -> bool:
+    index_name = str(index.get_name(schema))
+    return index_name in {
+        "std::fts::index",
+        "ext::pg_trgm::gin",
+        "ext::pg_trgm::gist",
+        "pg::gist",
+        "pg::gin",
+        "pg::brin",
+    }
+
+
 def is_subclass_or_tuple(
     ty: s_types.Type, parent: s_types.Type, schema: s_schema.Schema
 ) -> bool:
diff --git a/tests/schemas/pg_trgm.esdl b/tests/schemas/pg_trgm.esdl
index aee13d97f08..96fae0e80d6 100644
--- a/tests/schemas/pg_trgm.esdl
+++ b/tests/schemas/pg_trgm.esdl
@@ -26,6 +26,16 @@ type Gin extending Base {
     index ext::pg_trgm::gin on (.p_str);
 }
 
+type Gin2 extending Base {
+    p_str_2: str;
+    index ext::pg_trgm::gist on ((.p_str, .p_str_2));
+}
+
 type Gist extending Base {
     index ext::pg_trgm::gist on (.p_str);
 }
+
+type Gist2 extending Base {
+    p_str_2: str;
+    index ext::pg_trgm::gist on ((.p_str, .p_str_2));
+}
diff --git a/tests/schemas/pg_trgm_setup.edgeql b/tests/schemas/pg_trgm_setup.edgeql
index 0069f1fae18..ab1d2ae48f5 100644
--- a/tests/schemas/pg_trgm_setup.edgeql
+++ b/tests/schemas/pg_trgm_setup.edgeql
@@ -18,7 +18,14 @@
 
 for x in range_unpack(range(1, 1001)) union (
     insert Gist {
-        p_str := "qwertyu" ++ str_pad_start(<str>x, 4, "0")
+        p_str := "qwertyu" ++ str_pad_start(<str>x, 4, "0"),
+    }
+);
+
+for x in range_unpack(range(1, 1001)) union (
+    insert Gist2 {
+        p_str := "qwertyu" ++ str_pad_start(<str>x, 4, "0"),
+        p_str_2 := "iopasdf" ++ str_pad_start(<str>x, 4, "0"),
     }
 );
 
@@ -531,7 +538,12 @@ for x in {
     "Samarra School",
     "Jangal-e Marakeh Sar",
 } union (
-    insert Gist {
+    (insert Gist {
         p_str := x
-    }
+    })
+    union
+    (insert Gist2 {
+        p_str := x,
+        p_str_2 := x,
+    })
 );
diff --git a/tests/test_edgeql_ext_pg_trgm.py b/tests/test_edgeql_ext_pg_trgm.py
index 098fa2f81ff..139e482fa35 100644
--- a/tests/test_edgeql_ext_pg_trgm.py
+++ b/tests/test_edgeql_ext_pg_trgm.py
@@ -129,6 +129,47 @@ async def test_edgeql_ext_pg_trgm_similarity(self):
             index_type="ext::pg_trgm::gist",
         )
 
+        qry = """
+            SELECT
+                Gist2 {
+                    p_str,
+                    sim_dist := ext::pg_trgm::similarity_dist(
+                        .p_str, "q0987wertyu0988"
+                    ),
+                    p_str_2,
+                    sim_dist_2 := ext::pg_trgm::similarity_dist(
+                        .p_str_2, "q0987opasdf0988"
+                    ),
+                }
+            ORDER BY
+                .sim_dist EMPTY LAST THEN .sim_dist_2 EMPTY LAST
+            LIMIT
+                2
+        """
+
+        await self.assert_query_result(
+            qry,
+            [
+                {
+                    "p_str": "qwertyu0988",
+                    "sim_dist": 0.411765,
+                    "p_str_2": "iopasdf0988",
+                    "sim_dist_2": 0.5,
+                },
+                {
+                    "p_str": "qwertyu0987",
+                    "sim_dist": 0.5,
+                    "p_str_2": "iopasdf0987",
+                    "sim_dist_2": 0.57894737,
+                },
+            ]
+        )
+
+        await self.assert_index_use(
+            qry,
+            index_type="ext::pg_trgm::gist",
+        )
+
     async def test_edgeql_ext_pg_trgm_word_similarity(self):
         await self.assert_query_result(
             """
@@ -216,6 +257,43 @@ async def test_edgeql_ext_pg_trgm_word_similarity(self):
             index_type="ext::pg_trgm::gist",
         )
 
+        qry = """
+            SELECT
+                Gist2 {
+                    p_str,
+                    word_sim_dist := ext::pg_trgm::word_similarity_dist(
+                        "Kabankala", .p_str
+                    ),
+                    p_str_2,
+                    word_sim_dist_2 := ext::pg_trgm::word_similarity_dist(
+                        "Pub", .p_str_2
+                    )
+                }
+            ORDER BY
+                .word_sim_dist EMPTY LAST THEN .word_sim_dist_2 EMPTY LAST
+            LIMIT
+                2
+        """
+
+        await self.assert_query_result(
+            qry,
+            [
+                {
+                    "p_str": "Kabankala",
+                    "word_sim_dist": 0.0,
+                },
+                {
+                    "p_str": "Kabankalan City Public Plaza",
+                    "word_sim_dist": 0.1,
+                },
+            ]
+        )
+
+        await self.assert_index_use(
+            qry,
+            index_type="ext::pg_trgm::gist",
+        )
+
     async def test_edgeql_ext_pg_trgm_strict_word_similarity(self):
         await self.assert_query_result(
             """