tablets, mv: create tablets for a new materialized view

nyh · tgrabiec · commit 88a5ddabcec6 · 2023-11-28T21:54:32.000+01:00
Before this patch, trying to create a materialized view when tablets are enabled for a keyspace results in a failure: "Tablet map not found for table <uuid>", with uuid referring to the new view. When a table schema is created, the handler on_before_create_column_family() is called - and this function creates the tablet map for the new table. The bug was that we forgot to do the same when creating a materialized view - which also a bona-fide table. In this patch we call on_before_create_column_family() also when creating the materialized view. I decided *not* to create a new callback (e.g., on_before_create_view()) and rather call the existing on_before_create_column_family() callback - after all, a view is a column family too. This patch also includes a test for this issue, which fails to create the view before this patch, and passes with the patch. The test is in the test/topology_experimental_raft suite, which runs Scylla with the tablets experimental feature, and will also allow me to create tests that need multiple nodes. However, the first test added here only needs a single node to reproduce the bug and validate its fix. Fixes scylladb#16194. Signed-off-by: Nadav Har'El <nyh@scylladb.com> Closes scylladb#16205
diff --git a/service/migration_manager.cc b/service/migration_manager.cc
@@ -857,16 +857,23 @@ future<std::vector<mutation>> prepare_new_view_announcement(storage_proxy& sp, v
 #endif
     auto& db = sp.local_db();
     try {
-        auto&& keyspace = db.find_keyspace(view->ks_name()).metadata();
+        auto keyspace = db.find_keyspace(view->ks_name()).metadata();
         if (keyspace->cf_meta_data().contains(view->cf_name())) {
             throw exceptions::already_exists_exception(view->ks_name(), view->cf_name());
         }
         mlogger.info("Create new view: {}", view);
-        auto mutations = db::schema_tables::make_create_view_mutations(keyspace, std::move(view), ts);
-        co_return co_await include_keyspace(sp, *keyspace, std::move(mutations));
+        return seastar::async([&db, keyspace = std::move(keyspace), &sp, view = std::move(view), ts] {
+            auto mutations = db::schema_tables::make_create_view_mutations(keyspace, std::move(view), ts);
+            // We don't have a separate on_before_create_view() listener to
+            // call. But a view is also a column family, and we need to call
+            // the on_before_create_column_family listener - notably, to
+            // create tablets for the new view table.
+            db.get_notifier().before_create_column_family(*keyspace, *view, mutations, ts);
+            return include_keyspace(sp, *keyspace, std::move(mutations)).get();
+        });
     } catch (const replica::no_such_keyspace& e) {
-        auto&& ex = std::make_exception_ptr(exceptions::configuration_exception(format("Cannot add view '{}' to non existing keyspace '{}'.", view->cf_name(), view->ks_name())));
-        co_return coroutine::exception(std::move(ex));
+        return make_exception_future<std::vector<mutation>>(
+            exceptions::configuration_exception(format("Cannot add view '{}' to non existing keyspace '{}'.", view->cf_name(), view->ks_name())));
     }
 }
 
diff --git a/test/topology_experimental_raft/test_mv_tablets.py b/test/topology_experimental_raft/test_mv_tablets.py
@@ -0,0 +1,32 @@
+#
+# Copyright (C) 2023-present ScyllaDB
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+#
+
+# Tests for interaction of materialized views with *tablets*
+
+from test.pylib.manager_client import ManagerClient
+
+import pytest
+import asyncio
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+@pytest.mark.asyncio
+async def test_tablet_mv_create(manager: ManagerClient):
+    """A basic test for creating a materialized view on a table stored
+       with tablets on a one-node cluster. We just create the view and
+       delete it - that's it, we don't read or write the table.
+       Reproduces issue #16194.
+    """
+    servers = [await manager.server_add() for i in range(1)]
+    cql = manager.get_cql()
+
+    await cql.run_async("CREATE KEYSPACE test WITH replication = {'class': 'NetworkTopologyStrategy', 'replication_factor': 1, 'initial_tablets': 100}")
+    await cql.run_async("CREATE TABLE test.test (pk int PRIMARY KEY, c int)")
+    await cql.run_async("CREATE MATERIALIZED VIEW test.tv AS SELECT * FROM test.test WHERE c IS NOT NULL AND pk IS NOT NULL PRIMARY KEY (c, pk)")
+    await cql.run_async("DROP KEYSPACE test")
