[#23188] DocDB: Persist new colocated_id mapping discovered as part o…

…f processing CHANGE_METADATA_OP in xCluster ClusterConfig.

Summary:
Problem:

When a new table is added to a colocated database, the table needs to be created on both xCluster source and target with the same colocation_id.
As part of processing the ChangeMetadataOp for the AddTable operation received from the source, the target creates a mapping of source->target schema versions of the newly created table. However, this is not getting persisted in ClusterConfig if the source/target schema versions are default values. As a result while replication may work immediately after setup, upon a restart of the T-server, the mapping of source-target schema versions may be lost and replication may stall until another schema change happens on the source.

Fix:
Fix is to detect the non-existent colocation_id correctly and persisting the ClusterConfig.

Test Plan:
ybt xcluster_ysql_colocated-test XClusterYsqlColocatedTest.DatabaseReplication

The test was failing without the fix and is passing with the fix.

Reviewers: hsunder, xCluster

Reviewed By: hsunder

Subscribers: ybase

Differential Revision: https://phorge.dev.yugabyte.com/D36552

src/yb/integration-tests/xcluster/xcluster_ysql_colocated-test.cc

@@ -1,4 +1,4 @@
-// Copyright (c) YugabyteDB, Inc.
+// Copyright (c) YugaByte, Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 // in compliance with the License.  You may obtain a copy of the License at
@@ -23,6 +23,7 @@
 #include "yb/master/master_ddl.proxy.h"
 #include "yb/master/master_replication.proxy.h"
 #include "yb/master/mini_master.h"
+#include "yb/tserver/mini_tablet_server.h"
 #include "yb/util/backoff_waiter.h"
 
 DECLARE_bool(xcluster_wait_on_ddl_alter);
@@ -118,6 +119,7 @@ class XClusterYsqlColocatedTest : public XClusterYsqlTestBase {
       auto& tables = onlyColocated ? colocated_consumer_tables : consumer_tables_;
       for (const auto& consumer_table : tables) {
         LOG(INFO) << "Checking records for table " << consumer_table->name().ToString();
+        RETURN_NOT_OK(WaitForRowCount(consumer_table->name(), num_results, &consumer_cluster_));
         RETURN_NOT_OK(ValidateRows(consumer_table->name(), num_results, &consumer_cluster_));
       }
       return true;
@@ -196,28 +198,58 @@ class XClusterYsqlColocatedTest : public XClusterYsqlTestBase {
         [&]() -> Result<bool> {
           LOG(INFO) << "Checking records for table "
                     << new_colocated_consumer_table->name().ToString();
-          RETURN_NOT_OK(
-              ValidateRows(new_colocated_consumer_table->name(), kRecordBatch, &consumer_cluster_));
+          RETURN_NOT_OK(WaitForRowCount(
+              new_colocated_consumer_table->name(), kRecordBatch, &consumer_cluster_));
+          RETURN_NOT_OK(ValidateRows(
+              new_colocated_consumer_table->name(), kRecordBatch, &consumer_cluster_));
           return true;
         },
         MonoDelta::FromSeconds(20 * kTimeMultiplier),
         "IsDataReplicatedCorrectly new colocated table"));
 
-    // 6. Drop the new table and ensure that data is getting replicated correctly for
+    // 6. Shutdown the colocated tablet leader and verify that replication is still happening.
+    {
+      auto tablet_ids = ListTabletIdsForTable(consumer_cluster(), colocated_parent_table_id);
+      auto old_ts = FindTabletLeader(consumer_cluster(), *tablet_ids.begin());
+      old_ts->Shutdown();
+      const auto deadline = CoarseMonoClock::Now() + 10s * kTimeMultiplier;
+      RETURN_NOT_OK(WaitUntilTabletHasLeader(consumer_cluster(), *tablet_ids.begin(), deadline));
+      RETURN_NOT_OK(old_ts->RestartStoppedServer());
+      RETURN_NOT_OK(old_ts->WaitStarted());
+
+      RETURN_NOT_OK(InsertRowsInProducer(
+          kRecordBatch, 2 * kRecordBatch, new_colocated_producer_table,
+          use_transaction));
+
+      RETURN_NOT_OK(WaitFor(
+          [&]() -> Result<bool> {
+            LOG(INFO) << "Checking records for table "
+                      << new_colocated_consumer_table->name().ToString();
+            RETURN_NOT_OK(WaitForRowCount(
+                new_colocated_consumer_table->name(), 2 * kRecordBatch, &consumer_cluster_));
+            RETURN_NOT_OK(ValidateRows(
+                new_colocated_consumer_table->name(), 2 * kRecordBatch, &consumer_cluster_));
+            return true;
+      },
+          MonoDelta::FromSeconds(20 * kTimeMultiplier),
+          "IsDataReplicatedCorrectly new colocated table"));
+    }
+
+    // 7. Drop the new table and ensure that data is getting replicated correctly for
     // the other tables
     RETURN_NOT_OK(
         DropYsqlTable(&producer_cluster_, namespace_name, "", Format("test_table_$0", idx)));
     LOG(INFO) << Format("Dropped test_table_$0 on Producer side", idx);
 
-    // 7. Add additional data to the original tables.
+    // 8. Add additional data to the original tables.
     for (const auto& producer_table : producer_tables_) {
       LOG(INFO) << "Writing records for table " << producer_table->name().ToString();
       RETURN_NOT_OK(
           InsertRowsInProducer(count, count + kRecordBatch, producer_table, use_transaction));
     }
     count += kRecordBatch;
 
-    // 8. Verify all tables are properly replicated.
+    // 9. Verify all tables are properly replicated.
     RETURN_NOT_OK(WaitFor(
         [&]() -> Result<bool> { return data_replicated_correctly(count, false); },
         MonoDelta::FromSeconds(20 * kTimeMultiplier),

src/yb/master/xrepl_catalog_manager.cc

@@ -5670,16 +5670,22 @@ Status CatalogManager::UpdateConsumerOnProducerMetadata(
   schema_cached->Clear();
 
   cdc::SchemaVersionsPB* schema_versions_pb = nullptr;
+  bool schema_versions_updated = false;
 
   // TODO (#16557): Support remove_table_id() for colocated tables / tablegroups.
   if (IsColocationParentTableId(consumer_table_id) && req->colocation_id() != kColocationIdNotSet) {
     auto map = stream_entry->mutable_colocated_schema_versions();
-    schema_versions_pb = &((*map)[req->colocation_id()]);
+    schema_versions_pb = FindOrNull(*map, req->colocation_id());
+    if (nullptr == schema_versions_pb) {
+      // If the colocation_id itself does not exist, it needs to be recorded in clusterconfig.
+      // This is to handle the case where source-target schema version mapping is 0:0.
+      schema_versions_updated = true;
+      schema_versions_pb = &((*map)[req->colocation_id()]);
+    }
   } else {
     schema_versions_pb = stream_entry->mutable_schema_versions();
   }
 
-  bool schema_versions_updated = false;
   SchemaVersion current_producer_schema_version =
       schema_versions_pb->current_producer_schema_version();
   SchemaVersion current_consumer_schema_version =