From 74b76834489bc1e3feb32388c04decd7e5965f9a Mon Sep 17 00:00:00 2001
From: zhaoyiping0622 <zhaoyiping0622@gmail.com>
Date: Tue, 18 Jun 2024 12:06:13 +0000
Subject: [PATCH] [CP] add RPC to check server empty in executor

---
 .../engine/cmd/ob_alter_system_executor.cpp   | 42 ++++++++++++++++++-
 src/sql/engine/cmd/ob_alter_system_executor.h |  1 +
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/sql/engine/cmd/ob_alter_system_executor.cpp b/src/sql/engine/cmd/ob_alter_system_executor.cpp
index fec02d5f7..f18a985b6 100644
--- a/src/sql/engine/cmd/ob_alter_system_executor.cpp
+++ b/src/sql/engine/cmd/ob_alter_system_executor.cpp
@@ -666,7 +666,13 @@ int ObAdminServerExecutor::execute(ObExecContext &ctx, ObAdminServerStmt &stmt)
     if (OB_FAIL(ret)) {
       // nothing
     } else if (ObAdminServerArg::ADD == stmt.get_op()) {
-      if (OB_FAIL(common_proxy->add_server(arg))) {
+      ObSrvRpcProxy *rpc_proxy = NULL;
+      if (OB_ISNULL(rpc_proxy = task_exec_ctx->get_srv_rpc())) {
+        ret = OB_NOT_INIT;
+        LOG_WARN("get server rpc proxy failed", K(ret));
+      } else if (OB_FAIL(check_server_empty_(*rpc_proxy, arg.servers_))) {
+        LOG_WARN("failed to check server empty", KR(ret), K(arg));
+      } else if (OB_FAIL(common_proxy->add_server(arg))) {
         LOG_WARN("common rpc proxy add server failed", K(arg), K(ret));
       }
     } else if (ObAdminServerArg::CANCEL_DELETE == stmt.get_op()) {
@@ -718,6 +724,40 @@ int ObAdminServerExecutor::execute(ObExecContext &ctx, ObAdminServerStmt &stmt)
   return ret;
 }
 
+int ObAdminServerExecutor::check_server_empty_(obrpc::ObSrvRpcProxy &rpc_proxy, const obrpc::ObServerList &servers)
+{
+  int ret = OB_SUCCESS;
+  ObTimeoutCtx ctx;
+  int64_t timeout = 0;
+  uint64_t sys_tenant_data_version = 0;
+  if (OB_FAIL(rootserver::ObRootUtils::get_rs_default_timeout_ctx(ctx))) {
+    LOG_WARN("fail to get timeout ctx", KR(ret), K(ctx));
+  } else if (FALSE_IT(timeout = ctx.get_timeout())) {
+  } else if (OB_UNLIKELY(timeout <= 0)) {
+    ret = OB_TIMEOUT;
+    LOG_WARN("ctx time out", KR(ret), K(timeout));
+  } else if (OB_FAIL(GET_MIN_DATA_VERSION(OB_SYS_TENANT_ID, sys_tenant_data_version))) {
+    LOG_WARN("fail to get sys tenant's min data version", KR(ret));
+  } else {
+    Bool is_empty = false;
+    const ObCheckServerEmptyArg rpc_arg(ObCheckServerEmptyArg::ADD_SERVER, sys_tenant_data_version);
+    FOREACH_X(it, servers, OB_SUCC(ret)) {
+      const ObAddr &addr = *it;
+      is_empty = false;
+      if (OB_FAIL(rpc_proxy.to(addr)
+          .timeout(timeout)
+          .is_empty_server(rpc_arg, is_empty))) {
+        LOG_WARN("failed to check server empty", KR(ret));
+      } else if (!is_empty) {
+        ret = OB_OP_NOT_ALLOW;
+        LOG_WARN("adding non-empty server is not allowed", KR(ret));
+        LOG_USER_ERROR(OB_OP_NOT_ALLOW, "add non-empty server");
+      }
+    }
+  }
+  return ret;
+}
+
 int ObAdminServerExecutor::wait_leader_switch_out_(
     ObISQLClient &sql_proxy,
     const obrpc::ObServerList &svr_list)
diff --git a/src/sql/engine/cmd/ob_alter_system_executor.h b/src/sql/engine/cmd/ob_alter_system_executor.h
index 4c8898c32..5005ca479 100644
--- a/src/sql/engine/cmd/ob_alter_system_executor.h
+++ b/src/sql/engine/cmd/ob_alter_system_executor.h
@@ -197,6 +197,7 @@ private:
   int construct_wait_leader_switch_sql_(
       const obrpc::ObServerList &svr_list,
       ObSqlString &sql);
+  int check_server_empty_(obrpc::ObSrvRpcProxy &rpc_proxy, const obrpc::ObServerList &servers);
   DISALLOW_COPY_AND_ASSIGN(ObAdminServerExecutor);
 };