From 808e2cecbb4cb684bb3ae1d45e5a0da86bef28d1 Mon Sep 17 00:00:00 2001
From: Yoshiyuki Asaba <y-asaba at pgfoundry.org>
Date: Mon, 28 May 2007 01:26:12 +0000
Subject: [PATCH] pgpool did not failover when kind mismatch error occured
 using an extended query protocol. So if it occurs in Execute(), pgpool does
 failover.

---
 pool_auth.c          |  6 ++-
 pool_process_query.c | 88 +++++++++++++++++++-------------------------
 2 files changed, 42 insertions(+), 52 deletions(-)

diff --git a/pool_auth.c b/pool_auth.c
index 79ab132..9792ff5 100644
--- a/pool_auth.c
+++ b/pool_auth.c
@@ -1019,6 +1019,10 @@ int *pool_read_message_length2(POOL_CONNECTION_POOL *cp)
 	return &length_array[0];
 }
 
+/*
+ * return: -2 if kind does not match.
+ *         -1 if an error occured.
+ */
 signed char pool_read_kind(POOL_CONNECTION_POOL *cp)
 {
 	int status;
@@ -1044,7 +1048,7 @@ signed char pool_read_kind(POOL_CONNECTION_POOL *cp)
 		{
 			pool_error("read_kind: kind does not match between backends master(%d) secondary(%d)",
 					   kind, kind1);
-			return -1;
+			return -2;
 		}
 	}
 
diff --git a/pool_process_query.c b/pool_process_query.c
index 80000ef..6c42f1a 100644
--- a/pool_process_query.c
+++ b/pool_process_query.c
@@ -136,6 +136,7 @@ static PreparedStatement *lookup_prepared_statement_by_statement(PreparedStateme
 static PreparedStatement *lookup_prepared_statement_by_portal(PreparedStatementList *p, const char *name);
 static int send_deallocate(POOL_CONNECTION_POOL *backend, PreparedStatementList *p, int n);
 static char *normalize_prepared_stmt_name(const char *name);
+static POOL_STATUS error_kind_mismatch(POOL_CONNECTION *frontend, POOL_CONNECTION_POOL *backend, int kind, int kind1);
 
 static POOL_CONNECTION_POOL_SLOT *slots[MAX_CONNECTION_SLOTS];
 
@@ -321,31 +322,7 @@ POOL_STATUS pool_process_query(POOL_CONNECTION *frontend,
 					pool_read(SECONDARY(backend), &kind1, 1);
 					if (kind == '\0' || kind != kind1)
 					{
-						int sts;
-
-						pool_error("pool_process_query: kind does not match between backends master(%c) secondary(%c)",
-								   kind, kind1);
-						pool_send_error_message(frontend, MAJOR(backend), "XX000", 
-												"kind mismatch between backends", "",
-												"check data consistency between master and secondary", __FILE__, __LINE__);
-
-						/* health check */
-						sts = health_check();
-						if (sts == -1)
-						{
-							notice_backend_error(1);
-							exit(1);
-						}
-						else if (sts == -2)
-						{
-							notice_backend_error(0);
-							exit(1);
-						}
-
-						if (pool_config.replication_stop_on_mismatch)
-							return POOL_FATAL;
-						else
-							return POOL_ERROR;
+						return error_kind_mismatch(frontend, backend, kind, kind1);
 					}
 				}
 				pool_debug("read kind from backend pending data %c len: %d po: %d", kind, MASTER(backend)->len, MASTER(backend)->po);
@@ -406,31 +383,7 @@ POOL_STATUS pool_process_query(POOL_CONNECTION *frontend,
 
 			if (kind == '\0' || kind != kind1)
 			{
-				int sts;
-
-				pool_error("pool_process_query: kind does not match between backends master(%c) secondary(%c)",
-						   kind, kind1);
-				pool_send_error_message(frontend, MAJOR(backend), "XX000", 
-										"kind mismatch between backends", "",
-										"check data consistency between master and secondary", __FILE__, __LINE__);
-
-				/* health check */
-				sts = health_check();
-				if (sts == -1)
-				{
-					notice_backend_error(1);
-					exit(1);
-				}
-				else if (sts == -2)
-				{
-					notice_backend_error(0);
-					exit(1);
-				}
-
-				if (pool_config.replication_stop_on_mismatch)
-					return POOL_FATAL;
-				else
-					return POOL_ERROR;
+				return error_kind_mismatch(frontend, backend, kind, kind1);
 			}
 		}
 
@@ -911,7 +864,11 @@ static POOL_STATUS Execute(POOL_CONNECTION *frontend,
 	while ((kind = pool_read_kind(backend)),
 		   (kind != 'C' && kind != 'E' && kind != 'l' && kind != 's'))
 	{
-		if (kind < 0)
+		if (kind == -2) /* kind mismatch */
+		{
+			return error_kind_mismatch(frontend, backend, 0, 0);
+		}
+		else if (kind < 0)
 		{
 			pool_error("Execute: pool_read_kind error");
 			return POOL_ERROR;
@@ -3835,3 +3792,32 @@ static void query_ps_status(char *query, POOL_CONNECTION_POOL *backend)
 
 	set_ps_display(psbuf, false);
 }
+
+static POOL_STATUS error_kind_mismatch(POOL_CONNECTION *frontend, POOL_CONNECTION_POOL *backend, int kind, int kind1)
+{
+	int sts;
+
+	pool_error("pool_process_query: kind does not match between backends master(%c) secondary(%c)",
+			   kind, kind1);
+	pool_send_error_message(frontend, MAJOR(backend), "XX000", 
+							"kind mismatch between backends", "",
+							"check data consistency between master and secondary", __FILE__, __LINE__);
+
+	/* health check */
+	sts = health_check();
+	if (sts == -1)
+	{
+		notice_backend_error(1);
+		exit(1);
+	}
+	else if (sts == -2)
+	{
+		notice_backend_error(0);
+		exit(1);
+	}
+	
+	if (pool_config.replication_stop_on_mismatch)
+		return POOL_FATAL;
+	else
+		return POOL_ERROR;
+}
-- 
2.39.5