[BACKPORT 2.12][#11352] DocDB: Skip system tables for splitting

Summary:
Summary: Changes to fail the splitting of system tables early on Master during validation

Test Plan: Added a targeted unit test to ensure that system table splits fail early during validation

Original Differential Revision: https://phabricator.dev.yugabyte.com/D16146

Original Commit: 37c050a

Test Plan: ybd --cxx-test integration-tests_tablet-split-itest --gtest_filter TabletSplitITest.SplitSystemTable

Reviewers: asrivastava, bogdan

Reviewed By: bogdan

Subscribers: ybase

Differential Revision: https://phabricator.dev.yugabyte.com/D16430

src/yb/integration-tests/tablet-split-itest.cc

@@ -569,6 +569,28 @@ TEST_F(TabletSplitITest, SlowSplitSingleTablet) {
   ASSERT_OK(CreateSingleTabletAndSplit(kNumRows));
 }
 
+TEST_F(TabletSplitITest, SplitSystemTable) {
+  ANNOTATE_UNPROTECTED_WRITE(FLAGS_TEST_validate_all_tablet_candidates) = false;
+
+  auto* catalog_mgr = ASSERT_RESULT(catalog_manager());
+
+  // Attempt splits on "sys.catalog" and "tables" system tables and verify that they fail.
+  std::vector<master::TableInfoPtr> systables = {
+      catalog_mgr->GetTableInfo("sys.catalog.uuid"),
+      catalog_mgr->GetTableInfoFromNamespaceNameAndTableName(
+          YQL_DATABASE_CQL, "system_schema", "tables")};
+
+  for (const auto& systable : systables) {
+    for (const auto& tablet : systable->GetTablets()) {
+      LOG(INFO) << "Splitting : " << systable->name() << " Tablet :" << tablet->id();
+      auto s = catalog_mgr->TEST_SplitTablet(tablet, true /* select_all_tablets_for_split */);
+      LOG(INFO) << s.ToString();
+      EXPECT_TRUE(s.IsNotSupported());
+      LOG(INFO) << "Split of system table failed as expected";
+    }
+  }
+}
+
 TEST_F(TabletSplitITest, SplitTabletDuringReadWriteLoad) {
   constexpr auto kNumTablets = 3;
 

src/yb/master/tablet_split_manager.cc

@@ -168,6 +168,14 @@ Status TabletSplitManager::ValidateSplitCandidateTable(const TableInfo& table,
         "Tablet splitting is not supported for transaction status tables, table_id: $0",
         table.id());
   }
+  if (table.is_system()) {
+    VLOG(1) << Substitute("Tablet splitting is not supported for system table: $0 with "
+                          "table_id: $1", table.name(), table.id());
+    return STATUS_FORMAT(
+        NotSupported,
+        "Tablet splitting is not supported for system table: $0 with table_id: $1",
+        table.name(), table.id());
+  }
   if (table.GetTableType() == REDIS_TABLE_TYPE) {
     VLOG(1) << Substitute("Tablet splitting is not supported for YEDIS tables, table_id: $0",
                           table.id());