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  Disable an assert that will be no longer valid when consistent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, 13 insertions, 10 deletions

diff --git a/sql/ha_myisam.cc b/sql/ha_myisam.cc
index fefa05e92b0..8f3970d69e6 100644
--- a/sql/ha_myisam.cc
+++ b/sql/ha_myisam.cc
@@ -50,16 +50,19 @@ static handlerton myisam_hton= {
   "MyISAM",
   0,       /* slot */
   0,       /* savepoint size. */
-  0,       /* close_connection */
-  0,       /* savepoint */
-  0,       /* rollback to savepoint */
-  0,       /* release savepoint */
-  0,       /* commit */
-  0,       /* rollback */
-  0,       /* prepare */
-  0,       /* recover */
-  0,       /* commit_by_xid */
-  0,       /* rollback_by_xid */
+  NULL,    /* close_connection */
+  NULL,    /* savepoint */
+  NULL,    /* rollback to savepoint */
+  NULL,    /* release savepoint */
+  NULL,    /* commit */
+  NULL,    /* rollback */
+  NULL,    /* prepare */
+  NULL,    /* recover */
+  NULL,    /* commit_by_xid */
+  NULL,    /* rollback_by_xid */
+  NULL,    /* create_cursor_read_view */
+  NULL,    /* set_cursor_read_view */
+  NULL,    /* close_cursor_read_view */
   /*
     MyISAM doesn't support transactions and doesn't have
     transaction-dependent context: cursors can survive a commit.