pgpool2.git / summary / log / commit / refs

commit    1ea486c29e8f3ff5d9b1ae69f32e2dde56bc0302
Author:   Tatsuo Ishii <ishii@postgresql.org>
Date:     Sat Mar 31 01:03:51 2012 +0000

    Allow to use multi statement in master/slave mode. From 3.1
    transactional statements such as "BEGIN" are sent to not only primary
    but also standbys. This brings an unfortunate side effect: if the
    multi statement is "BEGIN;DELETE FROM table;END", this will be sent to
    standy as well and cause an error because standby does not allow write
    SQL. So fix is, if a query is a multi statement one, then send it to
    primary only.
    
    Committed to master and V3_1_STABLE.


 pool_proto_modules.c | 12 ++++++++++++
 pool_query_context.c | 21 +++++++++++++++++++++
 pool_query_context.h |  1 +
 3 files changed, 34 insertions(+)

diff --git a/pool_proto_modules.c b/pool_proto_modules.c
index 4afff9542..b455be200 100644
--- a/pool_proto_modules.c
+++ b/pool_proto_modules.c
@@ -249,6 +249,18 @@ POOL_STATUS SimpleQuery(POOL_CONNECTION *frontend,
 		 */
 		pool_start_query(query_context, contents, len, node);
 
+		/*
+		 * Check if multi statement query
+		 */
+		if (parse_tree_list && list_length(parse_tree_list) > 1)
+		{
+			query_context->is_multi_statement = true;
+		}
+		else
+		{
+			query_context->is_multi_statement = false;
+		}
+
 		if (PARALLEL_MODE)
 		{
 			bool parallel = true;
diff --git a/pool_query_context.c b/pool_query_context.c
index bd9fc1797..accc2942a 100644
--- a/pool_query_context.c
+++ b/pool_query_context.c
@@ -331,6 +331,27 @@ void pool_where_to_send(POOL_QUERY_CONTEXT *query_context, char *query, Node *no
 	{
 		pool_set_node_to_be_sent(query_context, REAL_MASTER_NODE_ID);
 	}
+	else if (MASTER_SLAVE && query_context->is_multi_statement)
+	{
+		/*
+		 * If we are in master/slave mode and we have multi stametemt
+		 * query, we should send it to primary server only. Otherwise
+		 * it is possible to send a write query to standby servers
+		 * because we only use the first element of the multi
+		 * statement query and don't care about the rest.  Typical
+		 * situation where we are bugged by this is, "BEGIN;DELETE
+		 * FROM table;END". Note that from pgpool-II 3.1.0
+		 * transactional statements such as "BEGIN" is unconditionaly
+		 * sent to all nodes(see send_to_where() for more details).
+		 * Someday we might be able to understand all part of multi
+		 * statement queries, but until that day we need this band
+		 * aid.
+		 */
+		if (query_context->is_multi_statement)
+		{
+			pool_set_node_to_be_sent(query_context, PRIMARY_NODE_ID);
+		}
+	}
 	else if (MASTER_SLAVE)
 	{
 		POOL_DEST dest;
diff --git a/pool_query_context.h b/pool_query_context.h
index 5fb0940e4..e4a50e243 100644
--- a/pool_query_context.h
+++ b/pool_query_context.h
@@ -57,6 +57,7 @@ typedef struct {
 	POOL_QUERY_STATE query_state[MAX_NUM_BACKENDS];	/* for extended query protocol */
 	bool is_cache_safe;	/* true if SELECT is safe to cache */
 	POOL_TEMP_QUERY_CACHE *temp_cache;	/* temporary cache */
+	bool is_multi_statement;	/* true if multi statement query */
 } POOL_QUERY_CONTEXT;
 
 extern POOL_QUERY_CONTEXT *pool_init_query_context(void);


[parent: a29cd65a642c]