From 7a8c30751587ff530e1ffff57e66530a2e235186 Mon Sep 17 00:00:00 2001
From: Markus Makela <markus.makela@mariadb.com>
Date: Wed, 24 Jun 2015 19:23:43 +0300
Subject: [PATCH] MXS-171: https://mariadb.atlassian.net/browse/MXS-171 Added
 option which allows the master server to be used for reads.

---
 Documentation/routers/ReadWriteSplit.md                | 7 +++++++
 server/modules/include/readwritesplit.h                | 1 +
 server/modules/routing/readwritesplit/readwritesplit.c | 7 ++++++-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Documentation/routers/ReadWriteSplit.md b/Documentation/routers/ReadWriteSplit.md
index 577bc2e36..e58367789 100644
--- a/Documentation/routers/ReadWriteSplit.md
+++ b/Documentation/routers/ReadWriteSplit.md
@@ -93,6 +93,13 @@ disable_sescmd_history=true
 disable_slave_recovery=true
 ```
 
+**`master_accept_reads`** allows the master server to be used for reads. This is a useful option to enable if you are using a small number of servers and wish to use the master for reads as well.
+
+```
+# Use the master for reads
+master_accept_reads=true
+```
+
 ## Limitations
 
 In Master-Slave replication cluster also read-only queries are routed to master too in the following situations:
diff --git a/server/modules/include/readwritesplit.h b/server/modules/include/readwritesplit.h
index 9aa55016f..c78cde5b4 100644
--- a/server/modules/include/readwritesplit.h
+++ b/server/modules/include/readwritesplit.h
@@ -252,6 +252,7 @@ typedef struct rwsplit_config_st {
         int               rw_max_sescmd_history_size;
         bool disable_sescmd_hist;
         bool disable_slave_recovery;
+        bool master_reads; /*< Use master for reads */
 } rwsplit_config_t;
      
 
diff --git a/server/modules/routing/readwritesplit/readwritesplit.c b/server/modules/routing/readwritesplit/readwritesplit.c
index b9beb80d0..7b4a808c3 100644
--- a/server/modules/routing/readwritesplit/readwritesplit.c
+++ b/server/modules/routing/readwritesplit/readwritesplit.c
@@ -1244,7 +1244,8 @@ static bool get_dcb(
 				SERVER_IS_SLAVE(b->backend_server) &&
 				(max_rlag == MAX_RLAG_UNDEFINED ||
 				(b->backend_server->rlag != MAX_RLAG_NOT_AVAILABLE &&
-				b->backend_server->rlag <= max_rlag)))
+				b->backend_server->rlag <= max_rlag)) &&
+				 !rses->rses_config.master_reads)
 			{
 				/** found slave */
 				candidate_bref = &backend_ref[i];
@@ -4589,6 +4590,10 @@ static void rwsplit_process_router_options(
 			{
 			    router->rwsplit_config.disable_slave_recovery = config_truth_value(value);
 			}
+			else if(strcmp(options[i],"master_accept_reads") == 0)
+			{
+			    router->rwsplit_config.master_reads = config_truth_value(value);
+			}
                 }
         } /*< for */
 }