#3681 [Colocated] Master should issue AddTableToTable only for subseq…

…uent tables.

Summary:
The very first table among colocated tables should not issue AddTableToTablet.

The issue was masked by the fact that issuing such an RPC before the CreateTablet RPC succeeded used to fail the RPC right away. The RPC was fixed to retry before giving up in D7943 (#3627). Subsequently, we've seen tservers running into DFATAL in the following tests.

./yb_build.sh --cxx-test pg_libpq-test --gtest_filter PgLibPqTest.TableColocation
./yb_build.sh --java-test org.yb.pgsql.TestPgRegressBetaFeatures

Test Plan:
./yb_build.sh --cxx-test pg_libpq-test --gtest_filter PgLibPqTest.TableColocation
./yb_build.sh --java-test org.yb.pgsql.TestPgRegressBetaFeatures

Reviewers: neha, mihnea, hector, bogdan, jason

Reviewed By: jason

Subscribers: ybase, yql

Differential Revision: https://phabricator.dev.yugabyte.com/D7987

src/yb/master/catalog_manager.cc

@@ -2114,9 +2114,12 @@ Status CatalogManager::CreateTable(const CreateTableRequestPB* orig_req,
   CHECK_EQ(SysTablesEntryPB::PREPARING, table->metadata().dirty().pb.state());
   if (tablets_exist) {
     TRACE("Inserted new table and updating tablet info into CatalogManager maps");
+    VLOG(1) << "Inserted new table and updating tablet info into "
+               "CatalogManager maps";
     s = sys_catalog_->UpdateItems(tablets, leader_ready_term_);
   } else {
     TRACE("Inserted new table and tablet info into CatalogManager maps");
+    VLOG(1) << "Inserted new table and tablet info into CatalogManager maps";
     for (const TabletInfo *tablet : tablets) {
       CHECK_EQ(SysTabletsEntryPB::PREPARING, tablet->metadata().dirty().pb.state());
     }
@@ -2167,7 +2170,7 @@ Status CatalogManager::CreateTable(const CreateTableRequestPB* orig_req,
     tablet->mutable_metadata()->CommitMutation();
   }
 
-  if (colocated) {
+  if (colocated && tablets_exist) {
     auto call =
         std::make_shared<AsyncAddTableToTablet>(master_, worker_pool_.get(), tablets[0], table);
     table->AddTask(call);

src/yb/tserver/tablet_service.cc

@@ -946,6 +946,7 @@ void TabletServiceAdminImpl::CreateTablet(const CreateTabletRequestPB* req,
   if (!CheckUuidMatchOrRespond(server_->tablet_manager(), "CreateTablet", req, resp, &context)) {
     return;
   }
+  DVLOG(3) << "Received CreateTablet RPC: " << yb::ToString(*req);
   TRACE_EVENT1("tserver", "CreateTablet",
                "tablet_id", req->tablet_id());
 
@@ -1125,6 +1126,7 @@ void TabletServiceAdminImpl::AddTableToTablet(
   if (!tablet) {
     return;
   }
+  DVLOG(3) << "Received AddTableToTablet RPC: " << yb::ToString(*req);
 
   tserver::ChangeMetadataRequestPB change_req;
   *change_req.mutable_add_table() = req->add_table();