A fix and a test case for Bug#10760 and complementary cleanups.

The idea of the patch
is that every cursor gets its own lock id for table level locking.
Thus cursors are protected from updates performed within the same 
connection. Additionally a list of transient (must be closed at
commit) cursors is maintained and all transient cursors are closed
when necessary. Lastly, this patch adds support for deadlock
timeouts to TLL locking when using cursors.
+ post-review fixes.

1 files changed, 20 insertions, 4 deletions

diff --git a/sql/sql_class.h b/sql/sql_class.h
index 6c4315b95fa..d6847f5fb35 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -756,7 +756,7 @@ class Cursor;
   be used explicitly.
 */
 
-class Statement: public Query_arena
+class Statement: public ilink, public Query_arena
 {
   Statement(const Statement &rhs);              /* not implemented: */
   Statement &operator=(const Statement &rhs);   /* non-copyable */
@@ -833,6 +833,8 @@ public:
   void restore_backup_statement(Statement *stmt, Statement *backup);
   /* return class type */
   virtual Type type() const;
+  /* Close the cursor open for this statement, if there is one */
+  virtual void close_cursor();
 };
 
 
@@ -884,15 +886,25 @@ public:
     }
     hash_delete(&st_hash, (byte *) statement);
   }
+  void add_transient_cursor(Statement *stmt)
+  { transient_cursor_list.append(stmt); }
+  void erase_transient_cursor(Statement *stmt) { stmt->unlink(); }
+  /*
+    Close all cursors of this connection that use tables of a storage
+    engine that has transaction-specific state and therefore can not
+    survive COMMIT or ROLLBACK. Currently all but MyISAM cursors are closed.
+  */
+  void close_transient_cursors();
   /* Erase all statements (calls Statement destructor) */
   void reset()
   {
     my_hash_reset(&names_hash);
     my_hash_reset(&st_hash);
+    transient_cursor_list.empty();
     last_found_statement= 0;
   }
 
-  ~Statement_map()
+  void destroy()
   {
     hash_free(&names_hash);
     hash_free(&st_hash);
@@ -900,6 +912,7 @@ public:
 private:
   HASH st_hash;
   HASH names_hash;
+  I_List<Statement> transient_cursor_list;
   Statement *last_found_statement;
 };
 
@@ -1017,8 +1030,7 @@ public:
   a thread/connection descriptor
 */
 
-class THD :public ilink,
-           public Statement,
+class THD :public Statement,
            public Open_tables_state
 {
 public:
@@ -1044,6 +1056,10 @@ public:
   struct  rand_struct rand;		// used for authentication
   struct  system_variables variables;	// Changeable local variables
   struct  system_status_var status_var; // Per thread statistic vars
+  THR_LOCK_INFO lock_info;              // Locking info of this thread
+  THR_LOCK_OWNER main_lock_id;          // To use for conventional queries
+  THR_LOCK_OWNER *lock_id;              // If not main_lock_id, points to
+                                        // the lock_id of a cursor.
   pthread_mutex_t LOCK_delete;		// Locked before thd is deleted
   /* all prepared statements and cursors of this connection */
   Statement_map stmt_map;