bzr push into mysql-trunk branch (mattias.jonsson:3757) WL#4443

[Mattias Jonsson]

 3757 Mattias Jonsson	2011-03-15 [merge]
      WL#4443 proof of concept.
      
      Prototype for designing WL#4443.
      
      Moved open_tables() and lock_tables()
      (was open_and_lock_tables()) into
      mysql_select/handle_select/mysql_union.
      
      Splitted JOIN::optimize to
      JOIN::optimize_before_locking +
      JOIN::optimize_after_locking
      
      
      Not yet done:
      Implement pruning for INSERT.
      Fix all problems with Items that uses tables
      in the prepare/optimize_before_locking stages.
      
      Updated with latest mysql-trunk

    added:
      mysql-test/r/wl4443.result
      mysql-test/t/wl4443.test
    modified:
      sql/ha_partition.cc
      sql/handler.h
      sql/item_row.cc
      sql/item_subselect.cc
      sql/opt_range.cc
      sql/sql_base.cc
      sql/sql_base.h
      sql/sql_delete.cc
      sql/sql_derived.cc
      sql/sql_derived.h
      sql/sql_insert.cc
      sql/sql_parse.cc
      sql/sql_select.cc
      sql/sql_select.h
      sql/sql_union.cc
      sql/sql_union.h
      sql/sql_update.cc
      sql/table.h

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