bzr commit into mysql-next-mr-bugfixing branch (jorgen.loland:3252) WL#5741

[Jorgen Loland]

#At file:///export/home/jl208045/mysql/wl4800/mysql-next-mr-opt-backporting-wl4800-range-subselect/ based on revid:guilhem.bichot@stripped

 3252 Jorgen Loland	2011-01-14
      WL#5741: Add optimizer tracing to subqueries
      
      Fix tracepoints so that all mtr test cases can be traced without 
      JSON syntax errors.
      
      Added DYNAMIC_RANGE and REPEATED_SUBSELECT tracing features to
      avoid repeated tracing of range analysis and execution, 
      respectively, of subselects.
     @ sql/item_subselect.cc
        Added Item_subselect::executed_before used to avoid tracing of 
        subquery execution when this happens repeatedly for each record
        in outer select.
     @ sql/item_subselect.h
        Added Item_subselect::executed_before used to avoid tracing of 
        subquery execution when this happens repeatedly for each record
        in outer select.
     @ sql/opt_range.cc
        Add tracepoints to range optimizer
     @ sql/sql_select.cc
        Add tracepoints to range optimizer

    added:
      mysql-test/r/optimizer_trace_subquery.result
      mysql-test/t/optimizer_trace_subquery.test
    modified:
      mysql-test/include/optimizer_trace.inc
      mysql-test/r/mysqld--help-notwin.result
      mysql-test/r/optimizer_trace2.result
      mysql-test/r/optimizer_trace_charset.result
      mysql-test/r/optimizer_trace_no_prot.result
      mysql-test/r/optimizer_trace_ps_prot.result
      mysql-test/r/optimizer_trace_range.result
      mysql-test/suite/sys_vars/r/optimizer_trace_features_basic.result
      mysql-test/t/optimizer_trace_range.test
      sql/item_subselect.cc
      sql/item_subselect.h
      sql/opt_range.cc
      sql/opt_trace.cc
      sql/opt_trace.h
      sql/sql_select.cc
      sql/sys_vars.cc

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