From c77bb502e986346f9f51153af733c37a4e8b2fc5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20M=C3=A4kel=C3=A4?= <markus.makela@mariadb.com>
Date: Tue, 24 Jan 2017 11:33:15 +0200
Subject: [PATCH] Store transaction type bit on transaction end

When the transaction ends, it's good to know what type of a transaction
just ended. Currently, this will be used by readwritesplit to detect when
a read-only transaction ends.
---
 include/maxscale/session.h                    | 49 ++++++++++++++++---
 server/core/session.c                         |  6 ++-
 .../protocol/MySQL/MySQLClient/mysql_client.c |  9 +++-
 3 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/include/maxscale/session.h b/include/maxscale/session.h
index 5cdd6237d..1012e57de 100644
--- a/include/maxscale/session.h
+++ b/include/maxscale/session.h
@@ -58,14 +58,17 @@ typedef enum
 typedef enum
 {
     /*< There is no on-going transaction. */
-    SESSION_TRX_INACTIVE    = SESSION_TRX_INACTIVE_BIT,
+    SESSION_TRX_INACTIVE          = SESSION_TRX_INACTIVE_BIT,
     /*< A transaction is active. */
-    SESSION_TRX_ACTIVE      = SESSION_TRX_ACTIVE_BIT,
+    SESSION_TRX_ACTIVE            = SESSION_TRX_ACTIVE_BIT,
     /*< An explicit READ ONLY transaction is active. */
-    SESSION_TRX_READ_ONLY   = (SESSION_TRX_ACTIVE_BIT | SESSION_TRX_READ_ONLY_BIT),
+    SESSION_TRX_READ_ONLY         = (SESSION_TRX_ACTIVE_BIT | SESSION_TRX_READ_ONLY_BIT),
     /*< An explicit READ WRITE transaction is active. */
-    SESSION_TRX_READ_WRITE  = (SESSION_TRX_ACTIVE_BIT | SESSION_TRX_READ_WRITE_BIT),
-    SESSION_TRX_ENDING      = SESSION_TRX_ENDING_BIT,
+    SESSION_TRX_READ_WRITE        = (SESSION_TRX_ACTIVE_BIT | SESSION_TRX_READ_WRITE_BIT),
+    /*< An explicit READ ONLY transaction is ending. */
+    SESSION_TRX_READ_ONLY_ENDING  = (SESSION_TRX_ENDING_BIT | SESSION_TRX_READ_ONLY_BIT),
+    /*< An explicit READ WRITE transaction is ending. */
+    SESSION_TRX_READ_WRITE_ENDING = (SESSION_TRX_ENDING_BIT | SESSION_TRX_READ_WRITE_BIT),
 } mxs_session_trx_state_t;
 
 /**
@@ -248,7 +251,7 @@ static inline bool session_trx_is_read_write(const MXS_SESSION* ses)
 }
 
 /**
- * Tells whether a  transaction is ending.
+ * Tells whether a transaction is ending.
  *
  * @see session_get_trx_state
  *
@@ -259,7 +262,39 @@ static inline bool session_trx_is_read_write(const MXS_SESSION* ses)
  */
 static inline bool session_trx_is_ending(const MXS_SESSION* ses)
 {
-    return ses->trx_state == SESSION_TRX_ENDING;
+    return ses->trx_state & SESSION_TRX_ENDING_BIT;
+}
+
+/**
+ * Tells whether a read-only transaction is ending.
+ *
+ * @see session_get_trx_state
+ *
+ * @note The return value is valid only if either a router or a filter
+ *       has declared that it needs RCAP_TYPE_TRANSACTION_TRACKING.
+ *
+ * @return True if a transaction that was active is ending either via COMMIT or
+ * ROLLBACK and it was a read-only transaction.
+ */
+static inline bool session_read_only_trx_is_ending(const MXS_SESSION* ses)
+{
+    return ses->trx_state == SESSION_TRX_READ_ONLY_ENDING;
+}
+
+/**
+ * Tells whether a read-write transaction is ending.
+ *
+ * @see session_get_trx_state
+ *
+ * @note The return value is valid only if either a router or a filter
+ *       has declared that it needs RCAP_TYPE_TRANSACTION_TRACKING.
+ *
+ * @return True if a transaction that was active is ending either via COMMIT or
+ * ROLLBACK and it was a read-write transaction.
+ */
+static inline bool session_read_write_trx_is_ending(const MXS_SESSION* ses)
+{
+    return ses->trx_state == SESSION_TRX_READ_WRITE_ENDING;
 }
 
 /**
diff --git a/server/core/session.c b/server/core/session.c
index 8059d9ff2..230e643bb 100644
--- a/server/core/session.c
+++ b/server/core/session.c
@@ -897,8 +897,10 @@ const char* session_trx_state_to_string(mxs_session_trx_state_t state)
         return "SESSION_TRX_READ_ONLY";
     case SESSION_TRX_READ_WRITE:
         return "SESSION_TRX_READ_WRITE";
-    case SESSION_TRX_ENDING:
-        return "SESSION_TRX_ENDING";
+    case SESSION_TRX_READ_ONLY_ENDING:
+        return "SESSION_TRX_READ_ONLY_ENDING";
+    case SESSION_TRX_READ_WRITE_ENDING:
+        return "SESSION_TRX_READ_WRITE_ENDING";
     }
 
     MXS_ERROR("Unknown session_trx_state_t value: %d", (int)state);
diff --git a/server/modules/protocol/MySQL/MySQLClient/mysql_client.c b/server/modules/protocol/MySQL/MySQLClient/mysql_client.c
index a4a106a1e..e870d6e01 100644
--- a/server/modules/protocol/MySQL/MySQLClient/mysql_client.c
+++ b/server/modules/protocol/MySQL/MySQLClient/mysql_client.c
@@ -1520,7 +1520,14 @@ static int route_by_statement(MXS_SESSION* session, uint64_t capabilities, GWBUF
                         }
                         else if ((type & QUERY_TYPE_COMMIT) || (type & QUERY_TYPE_ROLLBACK))
                         {
-                            session_set_trx_state(session, SESSION_TRX_ENDING);
+                            mxs_session_trx_state_t trx_state = session_get_trx_state(session);
+
+                            /** Remove the active transaction bit and set the end
+                             * of transaction bit */
+                            trx_state &= ~SESSION_TRX_ACTIVE_BIT;
+                            trx_state |= SESSION_TRX_ENDING_BIT;
+
+                            session_set_trx_state(session, trx_state);
 
                             if (type & QUERY_TYPE_ENABLE_AUTOCOMMIT)
                             {