WL#1563 - Modify MySQL to support fast CREATE/DROP INDEX

NDB cluster is not fully supported. This will be added with
WL 1892 (NDB Handler: Add support for CREATE/DROP INDEX).
Some preparatory code for this is already present though.
A change for the "duplicate key" error message is planned
for another changeset.


include/my_base.h:
  WL#1563 - Modify MySQL to support fast CREATE/DROP INDEX
  Defined a mask of flags which must be the same for two indexes
  if they should compare as compatible.
  Added an error number for a new drop index error message.
mysql-test/r/key.result:
  WL#1563 - Modify MySQL to support fast CREATE/DROP INDEX
  The test result.
mysql-test/t/key.test:
  WL#1563 - Modify MySQL to support fast CREATE/DROP INDEX
  The test case.
sql/handler.cc:
  WL#1563 - Modify MySQL to support fast CREATE/DROP INDEX
  Prepared for a later change in an error message:
  Replace index number by index name for "duplicate key" error.
  Added handling for the new drop index error message.
sql/handler.h:
  WL#1563 - Modify MySQL to support fast CREATE/DROP INDEX
  Added new flags and methods.
  Removed old flags and methods (from the last attempt).
sql/share/errmsg.txt:
  WL#1563 - Modify MySQL to support fast CREATE/DROP INDEX
  Added a new error message for drop index.
sql/sql_table.cc:
  WL#1563 - Modify MySQL to support fast CREATE/DROP INDEX
  Moved definitions to the top of the file.
  In mysql_prepare_table() allow an index to have the name
  "PRIMARY" if it has the key type "Key::PRIMARY".
  Added a parenthesis for readability.
  Removed old code from the last attempt.
  Some changes to compare_tables():
  - Input parameter "List<Key> *key_list" is replaced by
    "KEY *key_info_buffer, uint key_count".
  - Output parameters added: "index_drop_buffer/index_drop_count"
    and "index_add_buffer/index_add_count".
  - Key comparison must now find matching keys in changed
    old and new key lists.
  - Key comparison of a key is easier now because both old
    and new keys are of type 'KEY'.
  Call mysql_prepare_table() before compare_tables(). The
  translated KEY structs are needed at some places now.
  Inserted a code segment for checking alter_table_flags().
  Removed mysql_prepare_table() from the 'partition' branches
  (it is done above now).
  Removed a pair of unnecessary braces.
  Inserted a code segment for executing fast add/drop index.
  Made close of table dependent on whether it was opened.
  Prepared for NDB cluster support.
  Fixed commit to be called outside of LOCK_open.

sql/handler.h

@@ -110,8 +110,29 @@
 #define HA_KEYREAD_ONLY         64	/* Support HA_EXTRA_KEYREAD */
 
 /* bits in alter_table_flags */
-#define HA_ONLINE_ADD_EMPTY_PARTITION 1
-#define HA_ONLINE_DROP_PARTITION 2
+#define HA_ONLINE_ADD_EMPTY_PARTITION           0x00000001
+#define HA_ONLINE_DROP_PARTITION                0x00000002
+/*
+  These bits are set if different kinds of indexes can be created
+  off-line without re-create of the table (but with a table lock).
+*/
+#define HA_ONLINE_ADD_INDEX_NO_WRITES           0x00000004 /*add index w/lock*/
+#define HA_ONLINE_DROP_INDEX_NO_WRITES          0x00000008 /*drop index w/lock*/
+#define HA_ONLINE_ADD_UNIQUE_INDEX_NO_WRITES    0x00000010 /*add unique w/lock*/
+#define HA_ONLINE_DROP_UNIQUE_INDEX_NO_WRITES   0x00000020 /*drop uniq. w/lock*/
+#define HA_ONLINE_ADD_PK_INDEX_NO_WRITES        0x00000040 /*add prim. w/lock*/
+#define HA_ONLINE_DROP_PK_INDEX_NO_WRITES       0x00000080 /*drop prim. w/lock*/
+/*
+  These are set if different kinds of indexes can be created on-line
+  (without a table lock). If a handler is capable of one or more of
+  these, it should also set the corresponding *_NO_WRITES bit(s).
+*/
+#define HA_ONLINE_ADD_INDEX                     0x00000100 /*add index online*/
+#define HA_ONLINE_DROP_INDEX                    0x00000200 /*drop index online*/
+#define HA_ONLINE_ADD_UNIQUE_INDEX              0x00000400 /*add unique online*/
+#define HA_ONLINE_DROP_UNIQUE_INDEX             0x00000800 /*drop uniq. online*/
+#define HA_ONLINE_ADD_PK_INDEX                  0x00001000 /*add prim. online*/
+#define HA_ONLINE_DROP_PK_INDEX                 0x00002000 /*drop prim. online*/
 
 /*
   Index scan will not return records in rowid order. Not guaranteed to be
@@ -134,16 +155,6 @@
 */
 #define MAX_HA 15
 
-/*
-  Bits in index_ddl_flags(KEY *wanted_index)
-  for what ddl you can do with index
-  If none is set, the wanted type of index is not supported
-  by the handler at all. See WorkLog 1563.
-*/
-#define HA_DDL_SUPPORT   1 /* Supported by handler */
-#define HA_DDL_WITH_LOCK 2 /* Can create/drop with locked table */
-#define HA_DDL_ONLINE    4 /* Can create/drop without lock */
-
 /*
   Parameters for open() (in register form->filestat)
   HA_GET_INFO does an implicit HA_ABORT_IF_LOCKED
@@ -1442,11 +1453,13 @@ public:
   virtual void set_part_info(partition_info *part_info) { return; }
 #endif
   virtual ulong index_flags(uint idx, uint part, bool all_parts) const =0;
-  virtual ulong index_ddl_flags(KEY *wanted_index) const
-  { return (HA_DDL_SUPPORT); }
+
   virtual int add_index(TABLE *table_arg, KEY *key_info, uint num_of_keys)
   { return (HA_ERR_WRONG_COMMAND); }
-  virtual int drop_index(TABLE *table_arg, uint *key_num, uint num_of_keys)
+  virtual int prepare_drop_index(TABLE *table_arg, uint *key_num,
+                                 uint num_of_keys)
+  { return (HA_ERR_WRONG_COMMAND); }
+  virtual int final_drop_index(TABLE *table_arg)
   { return (HA_ERR_WRONG_COMMAND); }
 
   uint max_record_length() const