index: Set tombstone_gc when creating secondary index

Before this commit, when the underlying materialized view was created,
it didn't have the property `tombstone_gc` set to any value. That
was a bug and we fix it now.

Two reproducer tests is added for validation. They reproduce the problem
and don't pass before this commit.

Fixes scylladb/scylladb#26542

cql3/statements/create_index_statement.cc

@@ -34,6 +34,7 @@
 #include "index/secondary_index_manager.hh"
 #include "types/concrete_types.hh"
 #include "db/tags/extension.hh"
+#include "tombstone_gc_extension.hh"
 
 #include <stdexcept>
 
@@ -113,7 +114,9 @@ static data_type type_for_computed_column(cql3::statements::index_target::target
     }
 }
 
-view_ptr create_index_statement::create_view_for_index(const schema_ptr schema, const index_metadata& im) const {
+view_ptr create_index_statement::create_view_for_index(const schema_ptr schema, const index_metadata& im,
+        const data_dictionary::database& db) const
+{
     sstring index_target_name = im.options().at(cql3::statements::index_target::target_option_name);
     schema_builder builder{schema->ks_name(), secondary_index::index_table_name(im.name())};
     auto target_info = secondary_index::target_parser::parse(schema, im);
@@ -196,6 +199,10 @@ view_ptr create_index_statement::create_view_for_index(const schema_ptr schema,
         format("{} IS NOT NULL", index_target->name_as_cql_string()) :
         "";
     builder.with_view_info(schema, false, where_clause);
+
+    auto tombstone_gc_ext = seastar::make_shared<tombstone_gc_extension>(get_default_tombstone_gc_mode(db, schema->ks_name()));
+    builder.add_extension(tombstone_gc_extension::NAME, std::move(tombstone_gc_ext));
+
     // A local secondary index should be backed by a *synchronous* view,
     // see #16371. A view is marked synchronous with a tag. Non-local indexes
     // do not need the tags schema extension at all.
@@ -582,7 +589,7 @@ create_index_statement::prepare_schema_mutations(query_processor& qp, const quer
 
         // Produce the underlying view for the index.
         if (db::schema_tables::view_should_exist(res->index)) {
-            view_ptr view = create_view_for_index(cf.schema(), res->index);
+            view_ptr view = create_view_for_index(cf.schema(), res->index, qp.db());
             utils::chunked_vector<mutation> view_muts = co_await service::prepare_new_view_announcement(qp.proxy(), std::move(view), ts);
 
             muts.reserve(muts.size() + view_muts.size());

cql3/statements/create_index_statement.hh

@@ -54,7 +54,7 @@ public:
         index_metadata index;
     };
     std::optional<base_schema_with_new_index> build_index_schema(data_dictionary::database db) const;
-    view_ptr create_view_for_index(const schema_ptr, const index_metadata& im) const;
+    view_ptr create_view_for_index(const schema_ptr, const index_metadata& im, const data_dictionary::database&) const;
 private:
     void validate_for_local_index(const schema& schema) const;
     void validate_for_frozen_collection(const index_target& target) const;

test/cqlpy/test_secondary_index.py

@@ -2176,3 +2176,26 @@ def test_indexing_paging_and_aggregation(cql, test_keyspace):
         assert list(cql.execute(stmt)) == [(row_count * row_count // 4,)]
         stmt = SimpleStatement(f'SELECT avg(id) FROM {table} WHERE c2 = 1', fetch_size=3)
         assert list(cql.execute(stmt)) == [(row_count / 2 + 1,)]
+
+# Verify that a newly created secondary index has
+# the property `tombstone_gc` set to some value.
+#
+# Reproducer of scylladb/scylladb#26542
+def test_tombstone_gc_property(cql, test_keyspace, scylla_only):
+    with new_test_table(cql, test_keyspace, "p int PRIMARY KEY, v int") as table:
+        index_name = unique_name()
+        cql.execute(f"CREATE INDEX {index_name} ON {table}(v)")
+
+        desc_row = cql.execute(f"DESCRIBE MATERIALIZED VIEW {test_keyspace}.{index_name}_index").one()
+        assert "tombstone_gc = {" in desc_row.create_statement
+
+# Verify that a newly created unnamed secondary index has
+# the property `tombstone_gc` set to some value.
+#
+# Reproducer of scylladb/scylladb#26542
+def test_tombstone_gc_property_unnamed_index(cql, test_keyspace, scylla_only):
+    with new_test_table(cql, test_keyspace, "p int PRIMARY KEY, v int") as table:
+        cql.execute(f"CREATE INDEX ON {table}(v)")
+
+        desc_row = cql.execute(f"DESCRIBE MATERIALIZED VIEW {table}_v_idx_index").one()
+        assert "tombstone_gc = {" in desc_row.create_statement

tools/schema_loader.cc

@@ -334,7 +334,7 @@ std::vector<schema_ptr> do_load_schemas(const db::config& cfg, std::string_view
             }
             it->schema = std::move(new_base_schema);
             it->secondary_idx_man.reload();
-            auto view = p->create_view_for_index(it->schema, index);
+            auto view = p->create_view_for_index(it->schema, index, db);
             real_db.tables.emplace_back(dd_impl, dd_impl.unwrap(ks), view, true);
         } else if (auto p = dynamic_cast<cql3::statements::update_statement*>(statement)) {
             if (p->keyspace() != db::schema_tables::NAME && p->column_family() != db::schema_tables::DROPPED_COLUMNS) {