From 38a59b47672edd539b0486ea6dd7b44b12129775 Mon Sep 17 00:00:00 2001
From: Onur Tirtir <onurcantirtir@gmail.com>
Date: Thu, 13 Feb 2020 15:41:58 +0300
Subject: [PATCH] change ErrorIfTransactionAccessedPlacementsLocally logic &
 usages

---
 .../distributed/executor/adaptive_executor.c  |  8 +++--
 .../distributed/executor/local_executor.c     | 36 +++++++++++++++++++
 src/include/distributed/local_executor.h      |  1 +
 3 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/src/backend/distributed/executor/adaptive_executor.c b/src/backend/distributed/executor/adaptive_executor.c
index 3b9f7d531..76ce3d330 100644
--- a/src/backend/distributed/executor/adaptive_executor.c
+++ b/src/backend/distributed/executor/adaptive_executor.c
@@ -936,10 +936,12 @@ ExecuteTaskListExtended(RowModifyLevel modLevel, List *taskList,
 	ParamListInfo paramListInfo = NULL;
 
 	/*
-	 * The code-paths that rely on this function do not know how to execute
-	 * commands locally.
+	 * If current transaction accessed local placements and task list includes
+	 * tasks that should be executed locally (accessing any of the local placements),
+	 * then we should error out as it would cause inconsistencies across the
+	 * remote connection and local execution
 	 */
-	ErrorIfTransactionAccessedPlacementsLocally();
+	ErrorIfRemoteTaskExecutionOnLocallyAccessedNode(taskList);
 
 	if (MultiShardConnectionType == SEQUENTIAL_CONNECTION)
 	{
diff --git a/src/backend/distributed/executor/local_executor.c b/src/backend/distributed/executor/local_executor.c
index cf81ee4ee..2a418927e 100644
--- a/src/backend/distributed/executor/local_executor.c
+++ b/src/backend/distributed/executor/local_executor.c
@@ -592,6 +592,27 @@ ShouldExecuteTasksLocally(List *taskList)
 }
 
 
+/*
+ * AnyTaskAccessesLocalNode returns true if a task within the task list accesses
+ * to the local node.
+ */
+bool
+AnyTaskAccessesLocalNode(List *taskList)
+{
+	Task *task = NULL;
+
+	foreach_ptr(task, taskList)
+	{
+		if (TaskAccessesLocalNode(task))
+		{
+			return true;
+		}
+	}
+
+	return false;
+}
+
+
 /*
  * TaskAccessesLocalNode returns true if any placements of the task reside on
  * the node that we're executing the query.
@@ -614,6 +635,21 @@ TaskAccessesLocalNode(Task *task)
 }
 
 
+/*
+ * ErrorIfRemoteTaskExecutionOnLocallyAccessedNode errors out if the current
+ * transaction already accessed local placements in the current session(locally)
+ * and any of the given remote tasks will access a local placement.
+ */
+void
+ErrorIfRemoteTaskExecutionOnLocallyAccessedNode(List *remoteTaskList)
+{
+	if (AnyTaskAccessesLocalNode(remoteTaskList))
+	{
+		ErrorIfTransactionAccessedPlacementsLocally();
+	}
+}
+
+
 /*
  * ErrorIfTransactionAccessedPlacementsLocally errors out if a local query
  * on any shard has already been executed in the same transaction.
diff --git a/src/include/distributed/local_executor.h b/src/include/distributed/local_executor.h
index 8b11e096c..691c2804b 100644
--- a/src/include/distributed/local_executor.h
+++ b/src/include/distributed/local_executor.h
@@ -28,6 +28,7 @@ extern void ExtractLocalAndRemoteTasks(bool readOnlyPlan, List *taskList,
 extern bool ShouldExecuteTasksLocally(List *taskList);
 extern bool AnyTaskAccessesLocalNode(List *taskList);
 extern bool TaskAccessesLocalNode(Task *task);
+extern void ErrorIfRemoteTaskExecutionOnLocallyAccessedNode(List *taskList);
 extern void ErrorIfTransactionAccessedPlacementsLocally(void);
 extern void DisableLocalExecution(void);