can be specified
Currently MySQL allows one to specify what indexes to ignore during
join optimization. The scope of the current USE/FORCE/IGNORE INDEX 
statement is only the FROM clause, while all other clauses are not 
affected.

However, in certain cases, the optimizer
may incorrectly choose an index for sorting and/or grouping, and
produce an inefficient query plan.

This task provides the means to specify what indexes are
ignored/used for what operation in a more fine-grained manner, thus
making it possible to manually force a better plan. We do this
by extending the current IGNORE/USE/FORCE INDEX syntax to:

IGNORE/USE/FORCE INDEX [FOR {JOIN | ORDER | GROUP BY}]

so that:
- if no FOR is specified, the index hint will apply everywhere.
- if MySQL is started with the compatibility option --old_mode then
  an index hint without a FOR clause works as in 5.0 (i.e, the 
  index will only be ignored for JOINs, but can still be used to
  compute ORDER BY).

See the WL#3527 for further details.


BitKeeper/deleted/.del-mysqld.cc.rej:
  Rename: sql/mysqld.cc.rej -> BitKeeper/deleted/.del-mysqld.cc.rej
BitKeeper/deleted/.del-sql_parse.cc.rej:
  Rename: sql/sql_parse.cc.rej -> BitKeeper/deleted/.del-sql_parse.cc.rej
BitKeeper/deleted/.del-table.cc.rej:
  Rename: sql/table.cc.rej -> BitKeeper/deleted/.del-table.cc.rej
mysql-test/r/endspace.result:
  WL3527 : fixed undeterministic test
mysql-test/r/group_by.result:
  WL#3527: test cases
mysql-test/t/endspace.test:
  WL3527 : fixed undeterministic test
mysql-test/t/group_by.test:
  WL#3527: test cases
sql/item.cc:
  WL#3527: renames
sql/mysql_priv.h:
  WL#3527: corrected initialization
sql/mysqld.cc:
  WL#3527: added old_mode command line option
sql/opt_range.cc:
  WL#3527: renames
sql/sql_base.cc:
  WL#3527: 
   - renames
   - correct initialization
   - extended the processing of USE/FORCE/IGNORE index
sql/sql_class.h:
  WL#3527: added old_mode command line option
sql/sql_delete.cc:
  WL#3527: renames
sql/sql_help.cc:
  WL#3527: renames
sql/sql_lex.cc:
  WL#3527: extended parsing of USE/FORCE/IGNORE index
sql/sql_lex.h:
  WL#3527: extended parsing of USE/FORCE/IGNORE index
sql/sql_parse.cc:
  WL#3527: extended parsing of USE/FORCE/IGNORE index
sql/sql_select.cc:
  WL#3527:
   - renames
   - passing additional info to support the extended 
     USE/FORCE/IGNORE INDEX syntax
   - If there is a covering index, and we have 
     IGNORE INDEX FOR GROUP/ORDER, and this index is 
     used for the JOIN part, then we have to ignore the
     IGNORE INDEX FOR GROUP/ORDER.
sql/sql_show.cc:
  WL#3527: passing additional info to support the extended 
     USE/FORCE/IGNORE INDEX syntax
sql/sql_update.cc:
  WL#3527: renames
sql/sql_yacc.yy:
  WL#3527: extended parsing of USE/FORCE/IGNORE index
sql/table.cc:
  WL#3527: extended the processing of USE/FORCE/IGNORE index
sql/table.h:
  WL#3527: extended the processing of USE/FORCE/IGNORE index
storage/myisam/ha_myisam.cc:
  WL#3527: extended the processing of USE/FORCE/IGNORE index