Implement MySQL framework to support consistent read views in

cursors. This should fix Bug#11813 when InnoDB part is in 
(tested with a draft patch).
The idea of the patch is that if a storage engine supports
consistent read views, we open one when open a cursor,
set is as the active view when fetch from the cursor, and close
together with cursor close.


sql/examples/ha_archive.cc:
  - extend handlerton with cursors methods; fix coding style
sql/examples/ha_example.cc:
  - extend handlerton with cursors methods; fix coding style
sql/examples/ha_tina.cc:
  - extend handlerton with cursors methods; fix coding style
sql/ha_berkeley.cc:
  - extend handlerton with cursors methods
sql/ha_blackhole.cc:
  - extend handlerton with cursors methods; fix coding style
sql/ha_federated.cc:
  - extend handlerton with cursors methods; fix coding style
sql/ha_heap.cc:
  - extend handlerton with cursors methods; fix coding style
sql/ha_innodb.cc:
  - extend handlerton with cursors methods
sql/ha_myisam.cc:
  - extend handlerton with cursors methods; fix coding style
sql/ha_myisammrg.cc:
  - extend handlerton with cursors methods; fix coding style
sql/ha_ndbcluster.cc:
  - extend handlerton with cursors methods
sql/handler.h:
  - extend handlerton with cursors methods
sql/sql_select.cc:
  - create a consistent read view when we open a cursor,
    set it for a fetch, and free when we closing the cursor.
sql/sql_select.h:
  - add Cursor::ht_info to remember read views used in a cursor.
tests/mysql_client_test.c:
  Disable an assert that will be no longer valid when consistent
  read views in InnoDB are used.

1 files changed, 2 insertions, 0 deletions

diff --git a/tests/mysql_client_test.c b/tests/mysql_client_test.c
index 76d0ab2e4cc..78948548716 100644
--- a/tests/mysql_client_test.c
+++ b/tests/mysql_client_test.c
@@ -13874,10 +13874,12 @@ static void test_bug10760()
       printf("Fetched row %s\n", id_buf);
     rc= mysql_rollback(mysql);                  /* should close the cursor */
     myquery(rc);
+#if 0
     rc= mysql_stmt_fetch(stmt);
     DIE_UNLESS(rc);
     if (!opt_silent)
       printf("Got error (as expected): %s\n", mysql_error(mysql));
+#endif
   }
 
   mysql_stmt_close(stmt);