From bf4e0892717390bfb8e8866449d49c12658ceff0 Mon Sep 17 00:00:00 2001
From: Dmitry Yemanov <dyemanov@users.noreply.github.com>
Date: Fri, 13 Mar 2020 20:38:09 +0300
Subject: [PATCH] Fixed the sub-optimal plan reported by Vlad privately

---
 src/jrd/RecordSourceNodes.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/jrd/RecordSourceNodes.cpp b/src/jrd/RecordSourceNodes.cpp
index 3d2ba96cbc..5f75e756a3 100644
--- a/src/jrd/RecordSourceNodes.cpp
+++ b/src/jrd/RecordSourceNodes.cpp
@@ -2939,7 +2939,10 @@ void RseNode::pass1Source(thread_db* tdbb, CompilerScratch* csb, RseNode* rse,
 	// where we are just trying to inner join more than 2 streams. If possible,
 	// try to flatten the tree out before we go any further.
 
-	if (!rse->rse_jointype && !rse_jointype && !rse_sorted && !rse_projection &&
+	const auto isLateral = (this->flags & RseNode::FLAG_LATERAL) != 0;
+
+	if (!isLateral && !rse->rse_jointype && !rse_jointype &&
+		!rse_sorted && !rse_projection &&
 		!rse_first && !rse_skip && !rse_plan)
 	{
 		NestConst<RecordSourceNode>* arg = rse_relations.begin();