Rename connection params

src/backend/distributed/connection/connection_configuration.c

@@ -377,7 +377,7 @@ GetConnParams(ConnectionHashKey *key, char ***keywords, char ***values,
 		authParamsIdx++;
 	}
 
-	if (key->replication)
+	if (key->replicationConnParam)
 	{
 		connKeywords[authParamsIdx] = MemoryContextStrdup(context, "replication");
 		connValues[authParamsIdx] = MemoryContextStrdup(context, "database");

src/backend/distributed/connection/connection_management.c

@@ -290,13 +290,13 @@ StartNodeUserDatabaseConnection(uint32 flags, const char *hostname, int32 port,
 		strlcpy(key.database, CurrentDatabaseName(), NAMEDATALEN);
 	}
 
-	if (flags & EXCLUSIVE_AND_REPLICATION)
+	if (flags & REQUIRE_REPLICATION_CONNECTION_PARAM)
 	{
-		key.replication = true;
+		key.replicationConnParam = true;
 	}
 	else
 	{
-		key.replication = false;
+		key.replicationConnParam = false;
 	}
 
 	if (CurrentCoordinatedTransactionState == COORD_TRANS_NONE)
@@ -356,10 +356,6 @@ StartNodeUserDatabaseConnection(uint32 flags, const char *hostname, int32 port,
 	MultiConnection *connection = MemoryContextAllocZero(ConnectionContext,
 														 sizeof(MultiConnection));
 	connection->initilizationState = POOL_STATE_NOT_INITIALIZED;
-	if (flags & EXCLUSIVE_AND_REPLICATION)
-	{
-		connection->claimedExclusively = true;
-	}
 	dlist_push_tail(entry->connections, &connection->connectionNode);
 
 	/* these two flags are by nature cannot happen at the same time */
@@ -679,7 +675,7 @@ CloseConnection(MultiConnection *connection)
 
 	strlcpy(key.hostname, connection->hostname, MAX_NODE_LENGTH);
 	key.port = connection->port;
-	key.replication = connection->replication;
+	key.replicationConnParam = connection->requiresReplicationOption;
 	strlcpy(key.user, connection->user, NAMEDATALEN);
 	strlcpy(key.database, connection->database, NAMEDATALEN);
 
@@ -1224,7 +1220,7 @@ ConnectionHashHash(const void *key, Size keysize)
 	hash = hash_combine(hash, hash_uint32(entry->port));
 	hash = hash_combine(hash, string_hash(entry->user, NAMEDATALEN));
 	hash = hash_combine(hash, string_hash(entry->database, NAMEDATALEN));
-	hash = hash_combine(hash, hash_uint32(entry->replication));
+	hash = hash_combine(hash, hash_uint32(entry->replicationConnParam));
 
 	return hash;
 }
@@ -1238,7 +1234,7 @@ ConnectionHashCompare(const void *a, const void *b, Size keysize)
 
 	if (strncmp(ca->hostname, cb->hostname, MAX_NODE_LENGTH) != 0 ||
 		ca->port != cb->port ||
-		ca->replication != cb->replication ||
+		ca->replicationConnParam != cb->replicationConnParam ||
 		strncmp(ca->user, cb->user, NAMEDATALEN) != 0 ||
 		strncmp(ca->database, cb->database, NAMEDATALEN) != 0)
 	{
@@ -1266,7 +1262,7 @@ StartConnectionEstablishment(MultiConnection *connection, ConnectionHashKey *key
 	connection->port = key->port;
 	strlcpy(connection->database, key->database, NAMEDATALEN);
 	strlcpy(connection->user, key->user, NAMEDATALEN);
-	connection->replication = key->replication;
+	connection->requiresReplicationOption = key->replicationConnParam;
 
 	connection->pgConn = PQconnectStartParams((const char **) entry->keywords,
 											  (const char **) entry->values,

src/backend/distributed/operations/shard_split.c

@@ -771,7 +771,7 @@ DoSplitCopy(WorkerNode *sourceShardNode, List *sourceColocatedShardIntervalList,
 							 "BEGIN TRANSACTION ISOLATION LEVEL REPEATABLE READ;");
 			ddlCommandList = lappend(ddlCommandList, beginTransaction->data);
 
-			/* Set snapshot */
+			/* Set snapshot for non-blocking shard split. */
 			if (snapShotName != NULL)
 			{
 				StringInfo snapShotString = makeStringInfo();
@@ -779,7 +779,6 @@ DoSplitCopy(WorkerNode *sourceShardNode, List *sourceColocatedShardIntervalList,
 								 quote_literal_cstr(
 									 snapShotName));
 				ddlCommandList = lappend(ddlCommandList, snapShotString->data);
-				printf("Sameer final string snapshotted:%s\n", snapShotString->data);
 			}
 
 			ddlCommandList = lappend(ddlCommandList, splitCopyUdfCommand->data);
@@ -1584,7 +1583,7 @@ CreateTemplateReplicationSlotAndReturnSnapshot(ShardInterval *shardInterval,
 {
 	/*Create Template replication slot */
 	int connectionFlags = FORCE_NEW_CONNECTION;
-	connectionFlags |= EXCLUSIVE_AND_REPLICATION;
+	connectionFlags |= REQUIRE_REPLICATION_CONNECTION_PARAM;
 
 	MultiConnection *sourceConnection = GetNodeUserDatabaseConnection(connectionFlags,
 																	  sourceWorkerNode->

src/backend/distributed/replication/multi_logical_replication.c

@@ -2068,7 +2068,7 @@ GetSubscriptionPosition(MultiConnection *connection, Bitmapset *tableOwnerIds,
 }
 
 
-/*Refactor this for ShardMove too.*/
+/*TODO(saawasek):Refactor this for ShardMove too.*/
 void
 CreateShardSubscription(MultiConnection *connection, char *sourceNodeName,
 						int sourceNodePort, char *userName, char *databaseName,

src/backend/distributed/shardsplit/shardsplit_logical_replication.c

@@ -2,6 +2,8 @@
  *
  * shardsplit_logical_replication.c
  *
+ * Function definitions for logically replicating split children.
+ *
  * Copyright (c) Citus Data, Inc.
  *
  *-------------------------------------------------------------------------

src/include/distributed/connection_management.h

@@ -100,9 +100,15 @@ enum MultiConnectionMode
 	WAIT_FOR_CONNECTION = 1 << 7,
 
 	/*
-	 * Force Replication flags
+	 * Use the flag to start a connection for streaming replication.
+	 * This flag constructs additional libpq connection parameters needed for streaming
+	 * replication protocol. It adds 'replication=database' param which instructs
+	 * the backend to go into logical replication walsender mode.
+	 *  https://www.postgresql.org/docs/current/protocol-replication.html
+	 *
+	 * This is need to run 'CREATE_REPLICATION_SLOT' command.
 	 */
-	EXCLUSIVE_AND_REPLICATION = 1 << 8
+	REQUIRE_REPLICATION_CONNECTION_PARAM = 1 << 8
 };
 
 
@@ -193,7 +199,7 @@ typedef struct MultiConnection
 	uint64 copyBytesWrittenSinceLastFlush;
 
 	/* replication option */
-	bool replication;
+	bool requiresReplicationOption;
 
 	MultiConnectionStructInitializationState initilizationState;
 } MultiConnection;
@@ -215,7 +221,7 @@ typedef struct ConnectionHashKey
 	int32 port;
 	char user[NAMEDATALEN];
 	char database[NAMEDATALEN];
-	bool replication;
+	bool replicationConnParam;
 } ConnectionHashKey;
 
 /* hash entry */

src/include/distributed/shardsplit_logical_replication.h

@@ -2,6 +2,8 @@
  *
  * shardsplit_logical_replication.h
  *
+ * Function declarations for logically replicating split children.
+ *
  * Copyright (c) Citus Data, Inc.
  *
  *-------------------------------------------------------------------------