temp-namespace-comments.patch

diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index 3971346e73..f0f692fe09 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -3937,9 +3937,11 @@ InitTempTableNamespace(void)
 	 * Mark MyProc as owning this namespace which other processes can use to
 	 * decide if a temporary namespace is in use or not.  We assume that
 	 * assignment of namespaceId is an atomic operation.  Even if it is not,
-	 * the temporary relation which resulted in the creation of this temporary
-	 * namespace is still locked until the current transaction commits, so it
-	 * would not be accessible yet, acting as a barrier.
+	 * the lock acquired on the temporary relation which created this
+	 * namespace serves as a memory barrier which guarantees a value of
+	 * tempNamespaceId recent enough.  All the contents of this namespace will
+	 * become visible once the current transaction commits, releasing the lock
+	 * previously acquired.
 	 */
 	MyProc->tempNamespaceId = namespaceId;
 
@@ -3976,10 +3978,12 @@ AtEOXact_Namespace(bool isCommit, bool parallel)
 
 			/*
 			 * Reset the temporary namespace flag in MyProc.  We assume that
-			 * this operation is atomic.  Even if it is not, the temporary
-			 * table which created this namespace is still locked until this
-			 * transaction aborts so it would not be visible yet, acting as a
-			 * barrier.
+			 * this operation is atomic.  Even if it is not, the lock acquired
+			 * on the temporary table which created this namespace serves as a
+			 * memory barrier which guarantees a value of tempNamespaceId
+			 * recent enough.  Nothing from this temporary namespace will be
+			 * visible as this transaction aborts, releasing also the
+			 * previously-acquired lock.
 			 */
 			MyProc->tempNamespaceId = InvalidOid;
 		}
@@ -4037,10 +4041,12 @@ AtEOSubXact_Namespace(bool isCommit, SubTransactionId mySubid,
 
 			/*
 			 * Reset the temporary namespace flag in MyProc.  We assume that
-			 * this operation is atomic.  Even if it is not, the temporary
-			 * table which created this namespace is still locked until this
-			 * transaction aborts so it would not be visible yet, acting as a
-			 * barrier.
+			 * this operation is atomic.  Even if it is not, the lock acquired
+			 * on the temporary table which created this namespace serves as a
+			 * memory barrier which guarantees a value of tempNamespaceId
+			 * recent enough.  Nothing from this temporary namespace will be
+			 * visible as this transaction aborts, releasing also the
+			 * previously-acquired lock.
 			 */
 			MyProc->tempNamespaceId = InvalidOid;
 		}