Merge branch 'main' into speed-up-SequenceUsedInDistributedTable

src/backend/distributed/connection/connection_configuration.c

@@ -271,9 +271,24 @@ GetConnParams(ConnectionHashKey *key, char ***keywords, char ***values,
 	 * We allocate everything in the provided context so as to facilitate using
 	 * pfree on all runtime parameters when connections using these entries are
 	 * invalidated during config reloads.
+	 *
+	 * Also, when "host" is already provided in global parameters, we use hostname
+	 * from the key as "hostaddr" instead of "host" to avoid host name lookup. In
+	 * that case, the value for "host" becomes useful only if the authentication
+	 * method requires it.
 	 */
+	bool gotHostParamFromGlobalParams = false;
+	for (Size paramIndex = 0; paramIndex < ConnParams.size; paramIndex++)
+	{
+		if (strcmp(ConnParams.keywords[paramIndex], "host") == 0)
+		{
+			gotHostParamFromGlobalParams = true;
+			break;
+		}
+	}
+
 	const char *runtimeKeywords[] = {
-		"host",
+		gotHostParamFromGlobalParams ? "hostaddr" : "host",
 		"port",
 		"dbname",
 		"user",

src/backend/distributed/shared_library_init.c

@@ -2929,6 +2929,7 @@ NodeConninfoGucCheckHook(char **newval, void **extra, GucSource source)
 			#if defined(ENABLE_GSS) && defined(ENABLE_SSPI)
 		"gsslib",
 			#endif
+		"host",
 		"keepalives",
 		"keepalives_count",
 		"keepalives_idle",

src/test/regress/expected/node_conninfo_reload.out

@@ -520,5 +520,61 @@ show citus.node_conninfo;
 
 -- Should work again
 ALTER TABLE test ADD COLUMN e INT;
+-- show that we allow providing "host" param via citus.node_conninfo
+ALTER SYSTEM SET citus.node_conninfo = 'sslmode=require host=nosuchhost';
+SELECT pg_reload_conf();
+ pg_reload_conf
+---------------------------------------------------------------------
+ t
+(1 row)
+
+SELECT pg_sleep(0.1);
+ pg_sleep
+---------------------------------------------------------------------
+
+(1 row)
+
+-- fails due to invalid host
+SELECT COUNT(*)>=0 FROM test;
+WARNING:  connection to the remote node postgres@localhost:xxxxx failed with the following error: could not parse network address "localhost": Name or service not known
+ERROR:  connection to the remote node postgres@localhost:xxxxx failed with the following error: could not parse network address "localhost": Name or service not known
+SELECT array_agg(nodeid) as updated_nodeids from pg_dist_node WHERE nodename = 'localhost' \gset
+UPDATE pg_dist_node SET nodename = '127.0.0.1' WHERE nodeid = ANY(:'updated_nodeids'::int[]);
+ALTER SYSTEM SET citus.node_conninfo = 'sslmode=require host=localhost';
+SELECT pg_reload_conf();
+ pg_reload_conf
+---------------------------------------------------------------------
+ t
+(1 row)
+
+SELECT pg_sleep(0.1);
+ pg_sleep
+---------------------------------------------------------------------
+
+(1 row)
+
+-- works when hostaddr is specified in pg_dist_node after providing host in citus.node_conninfo
+SELECT COUNT(*)>=0 FROM test;
+ ?column?
+---------------------------------------------------------------------
+ t
+(1 row)
+
+-- restore original nodenames into pg_dist_node
+UPDATE pg_dist_node SET nodename = 'localhost' WHERE nodeid = ANY(:'updated_nodeids'::int[]);
+-- reset it
+ALTER SYSTEM RESET citus.node_conninfo;
+select pg_reload_conf();
+ pg_reload_conf
+---------------------------------------------------------------------
+ t
+(1 row)
+
+select pg_sleep(0.1); -- wait for config reload to apply
+ pg_sleep
+---------------------------------------------------------------------
+
+(1 row)
+
 DROP SCHEMA node_conninfo_reload CASCADE;
 NOTICE:  drop cascades to table test

src/test/regress/sql/node_conninfo_reload.sql

@@ -205,4 +205,30 @@ show citus.node_conninfo;
 -- Should work again
 ALTER TABLE test ADD COLUMN e INT;
 
+-- show that we allow providing "host" param via citus.node_conninfo
+ALTER SYSTEM SET citus.node_conninfo = 'sslmode=require host=nosuchhost';
+SELECT pg_reload_conf();
+SELECT pg_sleep(0.1);
+
+-- fails due to invalid host
+SELECT COUNT(*)>=0 FROM test;
+
+SELECT array_agg(nodeid) as updated_nodeids from pg_dist_node WHERE nodename = 'localhost' \gset
+UPDATE pg_dist_node SET nodename = '127.0.0.1' WHERE nodeid = ANY(:'updated_nodeids'::int[]);
+
+ALTER SYSTEM SET citus.node_conninfo = 'sslmode=require host=localhost';
+SELECT pg_reload_conf();
+SELECT pg_sleep(0.1);
+
+-- works when hostaddr is specified in pg_dist_node after providing host in citus.node_conninfo
+SELECT COUNT(*)>=0 FROM test;
+
+-- restore original nodenames into pg_dist_node
+UPDATE pg_dist_node SET nodename = 'localhost' WHERE nodeid = ANY(:'updated_nodeids'::int[]);
+
+-- reset it
+ALTER SYSTEM RESET citus.node_conninfo;
+select pg_reload_conf();
+select pg_sleep(0.1); -- wait for config reload to apply
+
 DROP SCHEMA node_conninfo_reload CASCADE;