From 43d3d73189fd7ee877a65d810a98c1022ba368b7 Mon Sep 17 00:00:00 2001
From: Joe Conway <mail@joeconway.com>
Date: Thu, 28 May 2020 13:45:06 -0400
Subject: [PATCH] Initialize dblink remoteConn struct in all cases

Two of the members of rconn were left uninitialized. When
dblink_open() is called without an outer transaction it
handles the initialization for us, but with an outer
transaction it does not. Arrange for initialization
in all cases. Backpatch to all supported versions.

Reported-by: Alexander Lakhin
Discussion: https://www.postgresql.org/message-id/flat/9bd0744f-5f04-c778-c5b3-809efe9c30c7%40joeconway.com#c545909a41664991aca60c4d70a10ce7
---
 contrib/dblink/dblink.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 81136b131c9..105f8fb5172 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -272,8 +272,13 @@ dblink_connect(PG_FUNCTION_ARGS)
 		conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0));
 
 	if (connname)
+	{
 		rconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext,
 												  sizeof(remoteConn));
+		rconn->conn = NULL;
+		rconn->openCursorCount = 0;
+		rconn->newXactForCursor = false;
+	}
 
 	/* first check for valid foreign data server */
 	connstr = get_connect_string(conname_or_str);