A fix and a test case for Bug#6513 "Test Suite: Values inserted by using

cursor is interpreted latin1 character and Bug#9819 "Cursors: Mysql Server
Crash while fetching from table with 5 million records."
A fix for a possible memory leak when fetching into an SP cursor
in a long loop.
The patch uses a common implementation of cursors in the binary protocol and 
in stored procedures and implements materialized cursors.
For implementation details, see comments in sql_cursor.cc


include/my_sys.h:
  - declaration for multi_alloc_root
libmysqld/Makefile.am:
  - drop protocol_cursor.cc, add sql_cursor.cc (replaces the old
  implementation of cursors with a new one)
mysql-test/r/ctype_ujis.result:
  - test results fixed (a test case for Bug#6513)
mysql-test/r/sp-big.result:
  - test results fixed (a test case for Bug#9819)
mysql-test/t/ctype_ujis.test:
  Add a test case for Bug#6513 "Test Suite: Values inserted by using cursor is
   interpreted latin1 character"
mysql-test/t/sp-big.test:
  Add a restricted test case for Bug#9819 "Cursors: Mysql Server Crash
  while fetching from table with 5 million records."
mysys/my_alloc.c:
  - an implementation of multi_alloc_root; this is largely a copy-paste
    from mulalloc.c, but the function is small and there is no easy way
    to reuse the existing C function.
sql/Makefile.am:
  - add sql_cursor.h, sql_cursor.cc (a new implementation of stored procedure
  cursors) and drop protocol_cursor.cc (the old one)
sql/handler.cc:
  - now TABLE object has its mem_root always initialized.
    Adjust the implementation handler::ha_open
sql/item_subselect.cc:
  - adjust to the changed declaration of st_select_lex_unit::prepare
sql/protocol.h:
  - drop Protocol_cursor
sql/sp_head.cc:
  - move juggling with Query_arena::free_list and Item::next to
    sp_eval_func_item, as this is needed in 3 places already.
sql/sp_head.h:
  - declare a no-op implementation for cleanup_stmt in sp_instr_cpush.
    This method is needed for non-materializing cursors, which are yet not 
    used in stored procedures.
  - declaration for sp_eval_func_item
sql/sp_rcontext.cc:
  - reimplement sp_cursor using the new implementation of server side cursors.
  - use sp_eval_func_item to assign values of SP variables from the
    row fetched from a cursor. This should fix a possible memory leak in 
    the old implementation of sp_cursor::fetch
sql/sp_rcontext.h:
  - reimplement sp_cursor using the new implementation of server side cursors.
sql/sql_class.cc:
  - disable the functionality that closes transient cursors at commit/rollback;
    transient cursors are not used in 5.0, instead we use materialized ones.
    To be enabled in a later version.
sql/sql_class.h:
  - adjust to the rename Cursor -> Server_side_cursor
  - additional declarations of select_union used in materialized cursors
sql/sql_derived.cc:
  - reuse bits of tmp table code in UNION, derived tables, and materialized
    cursors
  - cleanup comments
sql/sql_lex.h:
  - declarations of auxiliary methods used by materialized cursors
  - a cleanup in st_select_lex_unit interface
sql/sql_list.h:
  - add an array operator new[] to class Sql_alloc
sql/sql_prepare.cc:
  - split the tight coupling of cursors and prepared statements to reuse 
    the same implementation in stored procedures
  - cleanups of error processing in Prepared_statement::{prepare,execute}
sql/sql_select.cc:
  - move the implementation of sensitive (non-materializing) cursors to 
    sql_cursor.cc
  - make temporary tables self-contained: the table, its record and fields
    are allocated in TABLE::mem_root. This implementation is not clean
    and resets thd->mem_root several times because of the way create_tmp_table 
    works (many additional things are done inside it).
  - adjust to the changed declaration of st_select_lex_unit::prepare
sql/sql_select.h:
  - move the declaration of sensitive (non-materializing) cursors to 
    sql_cursor.cc
sql/sql_union.cc:
  - move pieces of st_select_unit::prepare to select_union and st_table
    methods to be able to reuse code in the implementation of materialized
    cursors
sql/sql_view.cc:
  - adjust to the changed signature of st_select_lex_unit::prepare
sql/table.cc:
  - implement auxiliary st_table methods for use with temporary tables
sql/table.h:
  - add declarations for auxiliary methods of st_table used to work with 
   temporary tables
tests/mysql_client_test.c:
  - if cursors are materialized, a parallel update of the table used
    in the cursor may go through: update the test.
sql/sql_cursor.cc:
  New BitKeeper file ``sql/sql_cursor.cc'' -- implementation of server side
  cursors
sql/sql_cursor.h:
  New BitKeeper file ``sql/sql_cursor.h'' - declarations for
  server side cursors.

1 files changed, 65 insertions, 0 deletions

diff --git a/sql/sql_cursor.h b/sql/sql_cursor.h
new file mode 100644
index 00000000000..d1156dfba8d
--- /dev/null
+++ b/sql/sql_cursor.h
@@ -0,0 +1,65 @@
+#ifndef _sql_cursor_h_
+#define _sql_cursor_h_
+/* Copyright (C) 2005 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#ifdef USE_PRAGMA_INTERFACE
+#pragma interface                              /* gcc class interface */
+#endif
+
+/*
+  Declarations for implementation of server side cursors. Only
+  read-only non-scrollable cursors are currently implemented.
+*/
+
+/*
+  Server_side_cursor -- an interface for materialized and
+  sensitive (non-materialized) implementation of cursors. All
+  cursors are self-contained (created in their own memory root).
+  For that reason they must be deleted only using a pointer to
+  Server_side_cursor, not to its base class.
+*/
+
+class Server_side_cursor: protected Query_arena, public Sql_alloc
+{
+protected:
+  /* Row destination used for fetch */
+  select_result *result;
+public:
+  Server_side_cursor(MEM_ROOT *mem_root_arg, select_result *result_arg)
+    :Query_arena(mem_root_arg, INITIALIZED), result(result_arg)
+  {}
+
+  virtual bool is_open() const= 0;
+
+  virtual int open(JOIN *top_level_join)= 0;
+  virtual void fetch(ulong num_rows)= 0;
+  virtual void close()= 0;
+  virtual ~Server_side_cursor();
+
+  static void operator delete(void *ptr, size_t size);
+};
+
+
+int mysql_open_cursor(THD *thd, uint flags,
+                      select_result *result,
+                      Server_side_cursor **res);
+
+/* Possible values for flags */
+
+enum { ANY_CURSOR= 1, ALWAYS_MATERIALIZED_CURSOR= 2 };
+
+#endif /* _sql_cusor_h_ */