v4-0001-Bugfix-in-logical-protocol-version.patch

From 14167267e79ddb9b4de66fd6fbd4a9653616b45d Mon Sep 17 00:00:00 2001
From: Dilip Kumar <dilipkumar@localhost.localdomain>
Date: Mon, 21 Sep 2020 17:15:01 +0530
Subject: [PATCH v4] Bugfix in logical protocol version

Revert the LOGICALREP_PROTO_VERSION_NUM and instead add a new
parameter to control the max protocol version we support.
---
 src/backend/replication/logical/worker.c    | 4 +++-
 src/backend/replication/pgoutput/pgoutput.c | 4 ++--
 src/include/replication/logicalproto.h      | 8 +++++---
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index 62c571e..1961f4a 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -3230,7 +3230,9 @@ ApplyWorkerMain(Datum main_arg)
 	options.logical = true;
 	options.startpoint = origin_startpos;
 	options.slotname = myslotname;
-	options.proto.logical.proto_version = LOGICALREP_PROTO_VERSION_NUM;
+	options.proto.logical.proto_version =
+		walrcv_server_version(wrconn) >= 140000 ?
+			LOGICALREP_PROTO_STREAM_VERSION_NUM : LOGICALREP_PROTO_VERSION_NUM;
 	options.proto.logical.publication_names = MySubscription->publications;
 	options.proto.logical.binary = MySubscription->binary;
 	options.proto.logical.streaming = MySubscription->stream;
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 729b655..174af7f 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -282,11 +282,11 @@ pgoutput_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
 								&enable_streaming);
 
 		/* Check if we support requested protocol */
-		if (data->protocol_version > LOGICALREP_PROTO_VERSION_NUM)
+		if (data->protocol_version > LOGICALREP_PROTO_MAX_VERSION_NUM)
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("client sent proto_version=%d but we only support protocol %d or lower",
-							data->protocol_version, LOGICALREP_PROTO_VERSION_NUM)));
+							data->protocol_version, LOGICALREP_PROTO_MAX_VERSION_NUM)));
 
 		if (data->protocol_version < LOGICALREP_PROTO_MIN_VERSION_NUM)
 			ereport(ERROR,
diff --git a/src/include/replication/logicalproto.h b/src/include/replication/logicalproto.h
index fb07580..33d719c 100644
--- a/src/include/replication/logicalproto.h
+++ b/src/include/replication/logicalproto.h
@@ -19,8 +19,9 @@
 /*
  * Protocol capabilities
  *
- * LOGICALREP_PROTO_VERSION_NUM is our native protocol and the greatest version
- * we can support. LOGICALREP_PROTO_MIN_VERSION_NUM is the oldest version we
+ * LOGICALREP_PROTO_VERSION_NUM is our native protocol.
+ * LOGICALREP_PROTO_MAX_VERSION_NUM is the greatest version we can support.
+ * LOGICALREP_PROTO_MIN_VERSION_NUM is the oldest version we
  * have backwards compatibility for. The client requests protocol version at
  * connect time.
  *
@@ -28,8 +29,9 @@
  * support for streaming large transactions.
  */
 #define LOGICALREP_PROTO_MIN_VERSION_NUM 1
+#define LOGICALREP_PROTO_VERSION_NUM 1
 #define LOGICALREP_PROTO_STREAM_VERSION_NUM 2
-#define LOGICALREP_PROTO_VERSION_NUM 2
+#define LOGICALREP_PROTO_MAX_VERSION_NUM LOGICALREP_PROTO_STREAM_VERSION_NUM
 
 /*
  * This struct stores a tuple received via logical replication.
-- 
1.8.3.1