From f4e8bf891ddf7de41283e3706e3fcd66e5127eed Mon Sep 17 00:00:00 2001
From: Ian Barwick <barwick@gmail.com>
Date: Wed, 28 Jun 2017 17:28:20 +0900
Subject: [PATCH] interim commit

---
 dbutils.c       | 11 ++++++-----
 repmgr--4.0.sql | 16 ++++++++++------
 repmgr.c        | 45 ++++++++++++++++++++++++++++++++++++++++++---
 repmgrd.c       |  9 +++++++--
 4 files changed, 65 insertions(+), 16 deletions(-)

diff --git a/dbutils.c b/dbutils.c
index da02c1b9..a83cb993 100644
--- a/dbutils.c
+++ b/dbutils.c
@@ -2292,14 +2292,13 @@ int	request_vote(PGconn *conn, int this_node_id, int this_node_priority, XLogRec
 {
 	PQExpBufferData	  query;
 	PGresult   *res;
-	int vote;
+	int lsn_diff;
 
 	initPQExpBuffer(&query);
 
 	appendPQExpBuffer(&query,
-					  "SELECT repmgr.request_vote(%i, %i, '%X/%X'::pg_lsn)",
+					  "SELECT repmgr.request_vote(%i, '%X/%X'::pg_lsn)",
 					  this_node_id,
-					  this_node_priority,
 					  (uint32) (last_wal_receive_lsn >> 32),
 					  (uint32) last_wal_receive_lsn);
 
@@ -2307,10 +2306,12 @@ int	request_vote(PGconn *conn, int this_node_id, int this_node_priority, XLogRec
 
 	termPQExpBuffer(&query);
 
-	vote = (strcmp(PQgetvalue(res, 0, 0), "t") == 0) ? 1 : 0;
+	lsn_diff = atoi(PQgetvalue(res, 0, 0));
+
+	log_debug("XXX lsn_diff %i", lsn_diff);
 
 	PQclear(res);
-	return vote;
+	return lsn_diff;
 }
 
 
diff --git a/repmgr--4.0.sql b/repmgr--4.0.sql
index ac57e98f..56937266 100644
--- a/repmgr--4.0.sql
+++ b/repmgr--4.0.sql
@@ -34,11 +34,15 @@ CREATE VIEW show_nodes AS
 LEFT JOIN nodes un
        ON un.node_id = n.upstream_node_id;
 
-CREATE FUNCTION request_vote(int) RETURNS boolean
-AS '$libdir/repmgr', 'request_vote'
-LANGUAGE C STRICT;
+/* repmgrd functions */
+
+CREATE FUNCTION request_vote(INT, pg_lsn)
+  RETURNS INT
+  AS '$libdir/repmgr', 'request_vote'
+  LANGUAGE C STRICT;
 
 
-CREATE FUNCTION get_voting_status() RETURNS int
-AS '$libdir/repmgr', 'get_voting_status'
-LANGUAGE C STRICT;
+CREATE FUNCTION get_voting_status()
+  RETURNS INT
+  AS '$libdir/repmgr', 'get_voting_status'
+  LANGUAGE C STRICT;
diff --git a/repmgr.c b/repmgr.c
index 97c77f78..cc712665 100644
--- a/repmgr.c
+++ b/repmgr.c
@@ -18,8 +18,16 @@
 #include "storage/shmem.h"
 #include "storage/spin.h"
 #include "utils/builtins.h"
+#include "utils/pg_lsn.h"
 #include "utils/timestamp.h"
 
+#include "executor/spi.h"
+#include "lib/stringinfo.h"
+#include "access/xact.h"
+#include "utils/snapmgr.h"
+#include "pgstat.h"
+
+
 #include "voting.h"
 
 #define MAXFNAMELEN		64
@@ -137,11 +145,42 @@ repmgr_shmem_startup(void)
 Datum
 request_vote(PG_FUNCTION_ARGS)
 {
-	uint32 node_id = PG_GETARG_INT32(0);
+	/* node_id used for logging purposes */
+	int requesting_node_id = PG_GETARG_INT32(0);
+	XLogRecPtr requesting_node_last_lsn = PG_GETARG_LSN(1);
+	StringInfoData	query;
 
-	elog(INFO, "id is %i", node_id);
+	int		ret;
+	bool	isnull;
 
-	PG_RETURN_BOOL(true);
+	int lsn_diff;
+
+	elog(INFO, "id is %i, lsn: %X/%X",
+		 requesting_node_id,
+		 (uint32) (requesting_node_last_lsn >> 32),
+		 (uint32) requesting_node_last_lsn);
+
+	SPI_connect();
+
+	initStringInfo(&query);
+	appendStringInfo(
+		&query,
+		"SELECT '%X/%X'::pg_lsn - pg_catalog.pg_last_wal_receive_lsn()::pg_lsn",
+		(uint32) (requesting_node_last_lsn >> 32),
+		(uint32) requesting_node_last_lsn);
+
+	ret = SPI_execute(query.data, false, 0);
+
+	lsn_diff = DatumGetInt32(SPI_getbinval(SPI_tuptable->vals[0],
+										   SPI_tuptable->tupdesc,
+										   1, &isnull));
+
+	elog(INFO, "XXX diff is %i",
+		 lsn_diff);
+
+   	SPI_finish();
+
+	PG_RETURN_INT32(lsn_diff);
 }
 
 
diff --git a/repmgrd.c b/repmgrd.c
index 8f33e51d..fe532317 100644
--- a/repmgrd.c
+++ b/repmgrd.c
@@ -483,8 +483,8 @@ monitor_streaming_standby(void)
 	// check result
 	(void) get_node_record(local_conn, local_node_info.upstream_node_id, &upstream_node_info);
 
-	// check result, fail if not up (must start on running node)
-	upstream_conn = establish_db_connection(config_file_options.conninfo, false);
+	// handle failure - do we want to loop here?
+	upstream_conn = establish_db_connection(upstream_node_info.conninfo, false);
 
 	// fix for cascaded standbys
 	primary_conn = upstream_conn;
@@ -635,8 +635,13 @@ do_election(void)
 									 local_node_info.node_id,
 									 local_node_info.priority,
 									 last_wal_receive_lsn);
+
+		PQfinish(cell->node_info->conn);
+		cell->node_info->conn = NULL;
 	}
 
+	log_notice(_("%i of of %i votes"), votes_for_me, visible_nodes);
+
 	return VS_VOTE_WON;
 }