[Backport 2.6] [#7126] PITR: Restore deleted table

Summary:
Adds the ability to restore the table that was previously deleted.
When the tablet that participates in the snapshot schedule is being deleted, it is marked as hidden instead of performing actual delete.
Such tablets reject reads and write, but could be restored to some point in time.

Cleanup for such tables should be implemented in follow-up diffs.

Original commit: D11389 / 9fd73c7

Test Plan:
ybd --gtest_filter YbAdminSnapshotScheduleTest.SnapshotScheduleUndeleteTable
Jenkins: rebase: 2.6

Reviewers: bogdan

Reviewed By: bogdan

Subscribers: ybase, mbautin, skedia, rahuldesirazu

Differential Revision: https://phabricator.dev.yugabyte.com/D11594

ent/src/yb/master/async_snapshot_tasks.cc

@@ -157,6 +157,7 @@ bool AsyncTabletSnapshotOp::SendRequest(int attempt) {
     req.set_schema_version(schema_version_);
     *req.mutable_schema() = schema_;
     *req.mutable_indexes() = indexes_;
+    req.set_hide(hide_);
   }
   req.set_propagated_hybrid_time(master_->clock()->Now().ToUint64());
 
@@ -186,5 +187,12 @@ void AsyncTabletSnapshotOp::Finished(const Status& status) {
   }
 }
 
+void AsyncTabletSnapshotOp::SetMetadata(const SysTablesEntryPB& pb) {
+  has_metadata_ = true;
+  schema_version_ = pb.version();
+  schema_ = pb.schema();
+  indexes_ = pb.indexes();
+}
+
 } // namespace master
 } // namespace yb

ent/src/yb/master/async_snapshot_tasks.h

@@ -48,13 +48,7 @@ class AsyncTabletSnapshotOp : public enterprise::RetryingTSRpcTask {
     snapshot_hybrid_time_ = value;
   }
 
-  void SetMetadata(uint32_t schema_version, const SchemaPB& schema,
-                   const google::protobuf::RepeatedPtrField<IndexInfoPB>& indexes) {
-    has_metadata_ = true;
-    schema_version_ = schema_version;
-    schema_ = schema;
-    indexes_ = indexes;
-  }
+  void SetMetadata(const SysTablesEntryPB& pb);
 
   void SetCallback(TabletSnapshotOperationCallback callback) {
     callback_ = std::move(callback);
@@ -79,6 +73,7 @@ class AsyncTabletSnapshotOp : public enterprise::RetryingTSRpcTask {
   uint32_t schema_version_;
   SchemaPB schema_;
   google::protobuf::RepeatedPtrField<IndexInfoPB> indexes_;
+  bool hide_ = false;
 };
 
 } // namespace master

ent/src/yb/master/catalog_manager.h

@@ -282,7 +282,8 @@ class CatalogManager : public yb::master::CatalogManager, SnapshotCoordinatorCon
 
   int64_t LeaderTerm() override;
 
-  Result<SnapshotSchedulesToTabletsMap> MakeSnapshotSchedulesToTabletsMap() override;
+  Result<SnapshotSchedulesToObjectIdsMap> MakeSnapshotSchedulesToObjectIdsMap(
+      SysRowEntry::Type type) override;
 
   static void SetTabletSnapshotsState(SysSnapshotEntryPB::State state,
                                       SysSnapshotEntryPB* snapshot_pb);

ent/src/yb/master/catalog_manager_ent.cc

@@ -1400,9 +1400,7 @@ void CatalogManager::SendRestoreTabletSnapshotRequest(
     call->SetSnapshotHybridTime(restore_at);
   }
   if (send_metadata) {
-    auto lock = tablet->table()->LockForRead();
-    const auto& pb = lock->pb;
-    call->SetMetadata(pb.version(), pb.schema(), pb.indexes());
+    call->SetMetadata(tablet->table()->LockForRead()->pb);
   }
   call->SetCallback(std::move(callback));
   tablet->table()->AddTask(call);
@@ -3435,8 +3433,9 @@ void CatalogManager::Started() {
   snapshot_coordinator_.Start();
 }
 
-Result<SnapshotSchedulesToTabletsMap> CatalogManager::MakeSnapshotSchedulesToTabletsMap() {
-  return snapshot_coordinator_.MakeSnapshotSchedulesToTabletsMap();
+Result<SnapshotSchedulesToObjectIdsMap> CatalogManager::MakeSnapshotSchedulesToObjectIdsMap(
+    SysRowEntry::Type type) {
+  return snapshot_coordinator_.MakeSnapshotSchedulesToObjectIdsMap(type);
 }
 
 void CatalogManager::SysCatalogLoaded(int64_t term) {

src/yb/common/snapshot.h

@@ -26,8 +26,8 @@ YB_STRONGLY_TYPED_UUID(TxnSnapshotId);
 YB_STRONGLY_TYPED_UUID(TxnSnapshotRestorationId);
 YB_STRONGLY_TYPED_UUID(SnapshotScheduleId);
 
-using SnapshotSchedulesToTabletsMap =
-    std::unordered_map<SnapshotScheduleId, std::vector<TabletId>, SnapshotScheduleIdHash>;
+using SnapshotSchedulesToObjectIdsMap =
+    std::unordered_map<SnapshotScheduleId, std::vector<std::string>, SnapshotScheduleIdHash>;
 
 } // namespace yb
 

src/yb/integration-tests/cassandra_cpp_driver-test.cc

@@ -2733,15 +2733,12 @@ TEST_F(CppCassandraDriverTest, BigQueryExpr) {
   }
 
   auto start = MonoTime::Now();
-  auto result = ASSERT_RESULT(session_.ExecuteWithResult(Format(
+  auto result = ASSERT_RESULT(session_.FetchValue<std::string>(Format(
       "SELECT MAX(key) FROM $0", kTableName)));
   auto finish = MonoTime::Now();
   LOG(INFO) << "Time: " << finish - start;
 
-  auto iterator = result.CreateIterator();
-  ASSERT_TRUE(iterator.Next());
-  LOG(INFO) << "Result: " << iterator.Row().Value(0).ToString();
-  ASSERT_FALSE(iterator.Next());
+  LOG(INFO) << "Result: " << result;
 }
 
 class CppCassandraDriverSmallSoftLimitTest : public CppCassandraDriverTest {

src/yb/integration-tests/cql_test_util.h

@@ -257,6 +257,15 @@ class CassandraSession {
     return ExecuteAndProcessOneRow(CassandraStatement(query), action);
   }
 
+  template <class T>
+  Result<T> FetchValue(const std::string& query) {
+    T result = T();
+    RETURN_NOT_OK(ExecuteAndProcessOneRow(query, [&result](const CassandraRow& row) {
+      result = row.Value(0).As<T>();
+    }));
+    return result;
+  }
+
   CHECKED_STATUS ExecuteBatch(const CassandraBatch& batch);
 
   CassandraFuture SubmitBatch(const CassandraBatch& batch);

src/yb/master/async_rpc_tasks.cc

@@ -618,14 +618,14 @@ void AsyncDeleteReplica::HandleResponse(int attempt) {
     if (table_) {
       LOG_WITH_PREFIX(INFO)
           << "TS " << permanent_uuid_ << ": tablet " << tablet_id_
-          << " (table " << table_->ToString() << ") successfully deleted";
+          << " (table " << table_->ToString() << ") successfully done";
     } else {
       LOG_WITH_PREFIX(WARNING)
           << "TS " << permanent_uuid_ << ": tablet " << tablet_id_
           << " did not belong to a known table, but was successfully deleted";
     }
     TransitionToCompleteState();
-    VLOG_WITH_PREFIX(1) << "TS " << permanent_uuid_ << ": delete complete on tablet " << tablet_id_;
+    VLOG_WITH_PREFIX(1) << "TS " << permanent_uuid_ << ": complete on tablet " << tablet_id_;
   }
 }
 
@@ -635,6 +635,9 @@ bool AsyncDeleteReplica::SendRequest(int attempt) {
   req.set_tablet_id(tablet_id_);
   req.set_reason(reason_);
   req.set_delete_type(delete_type_);
+  if (hide_only_) {
+    req.set_hide_only(hide_only_);
+  }
   if (cas_config_opid_index_less_or_equal_) {
     req.set_cas_config_opid_index_less_or_equal(*cas_config_opid_index_less_or_equal_);
   }

src/yb/master/async_rpc_tasks.h

@@ -368,7 +368,12 @@ class AsyncDeleteReplica : public RetrySpecificTSRpcTask {
   std::string type_name() const override { return "Delete Tablet"; }
 
   std::string description() const override {
-    return "Delete Tablet RPC for " + tablet_id_ + " on TS=" + permanent_uuid_;
+    return Format("$0 Tablet RPC for $1 on TS=$2",
+                  hide_only_ ? "Hide" : "Delete", tablet_id_, permanent_uuid_);
+  }
+
+  void set_hide_only(bool value) {
+    hide_only_ = value;
   }
 
  protected:
@@ -383,6 +388,7 @@ class AsyncDeleteReplica : public RetrySpecificTSRpcTask {
   const boost::optional<int64_t> cas_config_opid_index_less_or_equal_;
   const std::string reason_;
   tserver::DeleteTabletResponsePB resp_;
+  bool hide_only_ = false;
 };
 
 // Send the "Alter Table" with the latest table schema to the leader replica

src/yb/master/catalog_entity_info.cc

@@ -414,7 +414,8 @@ bool TableInfo::IsAlterInProgress(uint32_t version) const {
 bool TableInfo::AreAllTabletsDeleted() const {
   shared_lock<decltype(lock_)> l(lock_);
   for (const TableInfo::TabletInfoMap::value_type& e : tablet_map_) {
-    if (!e.second->LockForRead()->is_deleted()) {
+    auto tablet_lock = e.second->LockForRead();
+    if (!tablet_lock->is_deleted() && !tablet_lock->pb.hidden()) {
       return false;
     }
   }